A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Any method used for determining the location of and relative distances between genes on a chromosome.
Susceptibility of chromosomes to breakage leading to translocation; CHROMOSOME INVERSION; SEQUENCE DELETION; or other CHROMOSOME BREAKAGE related aberrations.
Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.
Specific loci that show up during KARYOTYPING as a gap (an uncondensed stretch in closer views) on a CHROMATID arm after culturing cells under specific conditions. These sites are associated with an increase in CHROMOSOME FRAGILITY. They are classified as common or rare, and by the specific culture conditions under which they develop. Fragile site loci are named by the letters "FRA" followed by a designation for the specific chromosome, and a letter which refers to which fragile site of that chromosome (e.g. FRAXA refers to fragile site A on the X chromosome. It is a rare, folic acid-sensitive fragile site associated with FRAGILE X SYNDROME.)
A species of ciliate protozoa used in genetic and cytological research.
Staining of bands, or chromosome segments, allowing the precise identification of individual chromosomes or parts of chromosomes. Applications include the determination of chromosome rearrangements in malformation syndromes and cancer, the chemistry of chromosome segments, chromosome changes during evolution, and, in conjunction with cell hybridization studies, chromosome mapping.
Clinical conditions caused by an abnormal chromosome constitution in which there is extra or missing chromosome material (either a whole chromosome or a chromosome segment). (from Thompson et al., Genetics in Medicine, 5th ed, p429)
The female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in human and other male-heterogametic species.
Actual loss of portion of a chromosome.
A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.
The homologous chromosomes that are dissimilar in the heterogametic sex. There are the X CHROMOSOME, the Y CHROMOSOME, and the W, Z chromosomes (in animals in which the female is the heterogametic sex (the silkworm moth Bombyx mori, for example)). In such cases the W chromosome is the female-determining and the male is ZZ. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.
Congenital disorder affecting all bone marrow elements, resulting in ANEMIA; LEUKOPENIA; and THROMBOPENIA, and associated with cardiac, renal, and limb malformations as well as dermal pigmentary changes. Spontaneous CHROMOSOME BREAKAGE is a feature of this disease along with predisposition to LEUKEMIA. There are at least 7 complementation groups in Fanconi anemia: FANCA, FANCB, FANCC, FANCD1, FANCD2, FANCE, FANCF, FANCG, and FANCL. (from Online Mendelian Inheritance in Man, http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=227650, August 20, 2004)
Very long DNA molecules and associated proteins, HISTONES, and non-histone chromosomal proteins (CHROMOSOMAL PROTEINS, NON-HISTONE). Normally 46 chromosomes, including two sex chromosomes are found in the nucleus of human cells. They carry the hereditary information of the individual.
Induction and quantitative measurement of chromosomal damage leading to the formation of micronuclei (MICRONUCLEI, CHROMOSOME-DEFECTIVE) in cells which have been exposed to genotoxic agents or IONIZING RADIATION.
The chromosomal constitution of cells which deviate from the normal by the addition or subtraction of CHROMOSOMES, chromosome pairs, or chromosome fragments. In a normally diploid cell (DIPLOIDY) the loss of a chromosome pair is termed nullisomy (symbol: 2N-2), the loss of a single chromosome is MONOSOMY (symbol: 2N-1), the addition of a chromosome pair is tetrasomy (symbol: 2N+2), the addition of a single chromosome is TRISOMY (symbol: 2N+1).
Mapping of the KARYOTYPE of a cell.
A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.
The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
The clear constricted portion of the chromosome at which the chromatids are joined and by which the chromosome is attached to the spindle during cell division.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Defective nuclei produced during the TELOPHASE of MITOSIS or MEIOSIS by lagging CHROMOSOMES or chromosome fragments derived from spontaneous or experimentally induced chromosomal structural changes.
A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.
A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.
An exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. Its frequency is increased by ultraviolet and ionizing radiation and other mutagenic agents and is particularly high in BLOOM SYNDROME.
A specific pair GROUP C CHROMSOMES of the human chromosome classification.
A specific pair of GROUP C CHROMSOMES of the human chromosome classification.
Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
An antiviral antibiotic produced by Cephalosporium aphidicola and other fungi. It inhibits the growth of eukaryotic cells and certain animal viruses by selectively inhibiting the cellular replication of DNA polymerase II or the viral-induced DNA polymerases. The drug may be useful for controlling excessive cell proliferation in patients with cancer, psoriasis or other dermatitis with little or no adverse effect upon non-multiplying cells.
Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.
Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.
A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.
The complete genetic complement contained in a set of CHROMOSOMES in a protozoan.
An increased tendency to acquire CHROMOSOME ABERRATIONS when various processes involved in chromosome replication, repair, or segregation are dysfunctional.
Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard X-rays are the higher energy, shorter wavelength X-rays. Soft x-rays or Grenz rays are less energetic and longer in wavelength. The short wavelength end of the X-ray spectrum overlaps the GAMMA RAYS wavelength range. The distinction between gamma rays and X-rays is based on their radiation source.
The medium-sized, submetacentric human chromosomes, called group C in the human chromosome classification. This group consists of chromosome pairs 6, 7, 8, 9, 10, 11, and 12 and the X chromosome.
A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.
A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A specific pair of GROUP B CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.
The alignment of CHROMOSOMES at homologous sequences.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of MAMMALS.
A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.
A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.
White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.
DNA constructs that are composed of, at least, a REPLICATION ORIGIN, for successful replication, propagation to and maintenance as an extra chromosome in bacteria. In addition, they can carry large amounts (about 200 kilobases) of other sequence for a variety of bioengineering purposes.
Deoxyribonucleic acid that makes up the genetic material of protozoa.
The human female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in humans.
A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.
The large, metacentric human chromosomes, called group A in the human chromosome classification. This group consists of chromosome pairs 1, 2, and 3.
A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.
A technique for visualizing CHROMOSOME ABERRATIONS using fluorescently labeled DNA probes which are hybridized to chromosomal DNA. Multiple fluorochromes may be attached to the probes. Upon hybridization, this produces a multicolored, or painted, effect with a unique color at each site of hybridization. This technique may also be used to identify cross-species homology by labeling probes from one species for hybridization with chromosomes from another species.
One of the two pairs of human chromosomes in the group B class (CHROMOSOMES, HUMAN, 4-5).
A Fanconi anemia complementation group protein that undergoes mono-ubiquitination by FANCL PROTEIN in response to DNA DAMAGE. Also, in response to IONIZING RADIATION it can undergo PHOSPHORYLATION by ataxia telangiectasia mutated protein. Modified FANCD2 interacts with BRCA2 PROTEIN in a stable complex with CHROMATIN, and it is involved in DNA REPAIR by homologous RECOMBINATION.
A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.
Chromosomes in which fragments of exogenous DNA ranging in length up to several hundred kilobase pairs have been cloned into yeast through ligation to vector sequences. These artificial chromosomes are used extensively in molecular biology for the construction of comprehensive genomic libraries of higher organisms.
A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.
The short, submetacentric human chromosomes, called group E in the human chromosome classification. This group consists of chromosome pairs 16, 17, and 18.
The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.
A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.
The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.
The medium-sized, acrocentric human chromosomes, called group D in the human chromosome classification. This group consists of chromosome pairs 13, 14, and 15.
The process by which a DNA molecule is duplicated.
An aberration in which a chromosomal segment is deleted and reinserted in the same place but turned 180 degrees from its original orientation, so that the gene sequence for the segment is reversed with respect to that of the rest of the chromosome.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
The short, acrocentric human chromosomes, called group G in the human chromosome classification. This group consists of chromosome pairs 21 and 22 and the Y chromosome.
A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.
Aberrant chromosomes with no ends, i.e., circular.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
The mechanisms of eukaryotic CELLS that place or keep the CHROMOSOMES in a particular SUBNUCLEAR SPACE.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
The large, submetacentric human chromosomes, called group B in the human chromosome classification. This group consists of chromosome pairs 4 and 5.
A dosage compensation process occurring at an early embryonic stage in mammalian development whereby, at random, one X CHROMOSOME of the pair is repressed in the somatic cells of females.
A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.
Any cell, other than a ZYGOTE, that contains elements (such as NUCLEI and CYTOPLASM) from two or more different cells, usually produced by artificial CELL FUSION.
The phase of cell nucleus division following PROMETAPHASE, in which the CHROMOSOMES line up across the equatorial plane of the SPINDLE APPARATUS prior to separation.
Structures within the CELL NUCLEUS of insect cells containing DNA.
Established cell cultures that have the potential to propagate indefinitely.
Structures which are contained in or part of CHROMOSOMES.
The short, metacentric human chromosomes, called group F in the human chromosome classification. This group consists of chromosome pairs 19 and 20.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.
The total relative probability, expressed on a logarithmic scale, that a linkage relationship exists among selected loci. Lod is an acronym for "logarithmic odds."
A variety of simple repeat sequences that are distributed throughout the GENOME. They are characterized by a short repeat unit of 2-8 basepairs that is repeated up to 100 times. They are also known as short tandem repeats (STRs).
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
Interruptions in the sugar-phosphate backbone of DNA.
Either of the two longitudinally adjacent threads formed when a eukaryotic chromosome replicates prior to mitosis. The chromatids are held together at the centromere. Sister chromatids are derived from the same chromosome. (Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)
A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.
The possession of a third chromosome of any one type in an otherwise diploid cell.
Nucleoproteins, which in contrast to HISTONES, are acid insoluble. They are involved in chromosomal functions; e.g. they bind selectively to DNA, stimulate transcription resulting in tissue-specific RNA synthesis and undergo specific changes in response to various hormones or phytomitogens.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The failure of homologous CHROMOSOMES or CHROMATIDS to segregate during MITOSIS or MEIOSIS with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none.
DNA constructs that are composed of, at least, all elements, such as a REPLICATION ORIGIN; TELOMERE; and CENTROMERE, required for successful replication, propagation to and maintainance in progeny human cells. In addition, they are constructed to carry other sequences for analysis or gene transfer.
Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.
A microtubule structure that forms during CELL DIVISION. It consists of two SPINDLE POLES, and sets of MICROTUBULES that may include the astral microtubules, the polar microtubules, and the kinetochore microtubules.
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Failure of equipment to perform to standard. The failure may be due to defects or improper use.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
A technique with which an unknown region of a chromosome can be explored. It is generally used to isolate a locus of interest for which no probe is available but that is known to be linked to a gene which has been identified and cloned. A fragment containing a known gene is selected and used as a probe to identify other overlapping fragments which contain the same gene. The nucleotide sequences of these fragments can then be characterized. This process continues for the length of the chromosome.
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.
Species- or subspecies-specific DNA (including COMPLEMENTARY DNA; conserved genes, whole chromosomes, or whole genomes) used in hybridization studies in order to identify microorganisms, to measure DNA-DNA homologies, to group subspecies, etc. The DNA probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the DNA probe include the radioisotope labels 32P and 125I and the chemical label biotin. The use of DNA probes provides a specific, sensitive, rapid, and inexpensive replacement for cell culture techniques for diagnosing infections.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.
A species of fruit fly much used in genetics because of the large size of its chromosomes.
Genetic loci associated with a QUANTITATIVE TRAIT.
The interval between two successive CELL DIVISIONS during which the CHROMOSOMES are not individually distinguishable. It is composed of the G phases (G1 PHASE; G0 PHASE; G2 PHASE) and S PHASE (when DNA replication occurs).
The occurrence in an individual of two or more cell populations of different chromosomal constitutions, derived from a single ZYGOTE, as opposed to CHIMERISM in which the different cell populations are derived from more than one zygote.
The genetic constitution of individuals with respect to one member of a pair of allelic genes, or sets of genes that are closely linked and tend to be inherited together such as those of the MAJOR HISTOCOMPATIBILITY COMPLEX.
An individual having different alleles at one or more loci regarding a specific character.
An aberration in which an extra chromosome or a chromosomal segment is made.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
A characteristic symptom complex.
Highly repetitive DNA sequences found in HETEROCHROMATIN, mainly near centromeres. They are composed of simple sequences (very short) (see MINISATELLITE REPEATS) repeated in tandem many times to form large blocks of sequence. Additionally, following the accumulation of mutations, these blocks of repeats have been repeated in tandem themselves. The degree of repetition is on the order of 1000 to 10 million at each locus. Loci are few, usually one or two per chromosome. They were called satellites since in density gradients, they often sediment as distinct, satellite bands separate from the bulk of genomic DNA owing to a distinct BASE COMPOSITION.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.
A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.
The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
Examination of CHROMOSOMES to diagnose, classify, screen for, or manage genetic diseases and abnormalities. Following preparation of the sample, KARYOTYPING is performed and/or the specific chromosomes are analyzed.
The locations in specific DNA sequences where CHROMOSOME BREAKS have occurred.
Genes that influence the PHENOTYPE only in the homozygous state.
The complete genetic complement contained in the DNA of a set of CHROMOSOMES in a HUMAN. The length of the human genome is about 3 billion base pairs.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
DNA TOPOISOMERASES that catalyze ATP-dependent breakage of both strands of DNA, passage of the unbroken strands through the breaks, and rejoining of the broken strands. These enzymes bring about relaxation of the supercoiled DNA and resolution of a knotted circular DNA duplex.
The chromosomal constitution of cells, in which each type of CHROMOSOME is represented once. Symbol: N.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Extra large CHROMOSOMES, each consisting of many identical copies of a chromosome lying next to each other in parallel.
Genotypic differences observed among individuals in a population.
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
DNA present in neoplastic tissue.
A selective increase in the number of copies of a gene coding for a specific protein without a proportional increase in other genes. It occurs naturally via the excision of a copy of the repeating sequence from the chromosome and its extrachromosomal replication in a plasmid, or via the production of an RNA transcript of the entire repeating sequence of ribosomal RNA followed by the reverse transcription of the molecule to produce an additional copy of the original DNA sequence. Laboratory techniques have been introduced for inducing disproportional replication by unequal crossing over, uptake of DNA from lysed cells, or generation of extrachromosomal sequences from rolling circle replication.
The first phase of cell nucleus division, in which the CHROMOSOMES become visible, the CELL NUCLEUS starts to lose its identity, the SPINDLE APPARATUS appears, and the CENTRIOLES migrate toward opposite poles.
The number of copies of a given gene present in the cell of an organism. An increase in gene dosage (by GENE DUPLICATION for example) can result in higher levels of gene product formation. GENE DOSAGE COMPENSATION mechanisms result in adjustments to the level GENE EXPRESSION when there are changes or differences in gene dosage.
The loss of one allele at a specific locus, caused by a deletion mutation; or loss of a chromosome from a chromosome pair, resulting in abnormal HEMIZYGOSITY. It is detected when heterozygous markers for a locus appear monomorphic because one of the ALLELES was deleted.
The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Deoxyribonucleic acid that makes up the genetic material of fungi.
A subdiscipline of genetics which deals with the cytological and molecular analysis of the CHROMOSOMES, and location of the GENES on chromosomes, and the movements of chromosomes during the CELL CYCLE.
The full set of CHROMOSOMES presented as a systematized array of METAPHASE chromosomes from a photomicrograph of a single CELL NUCLEUS arranged in pairs in descending order of size and according to the position of the CENTROMERE. (From Stedman, 25th ed)
Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.
Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.
An individual in which both alleles at a given locus are identical.
A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
Genes whose loss of function or gain of function MUTATION leads to the death of the carrier prior to maturity. They may be essential genes (GENES, ESSENTIAL) required for viability, or genes which cause a block of function of an essential gene at a time when the essential gene function is required for viability.
Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each.
Clinical conditions caused by an abnormal sex chromosome constitution (SEX CHROMOSOME ABERRATIONS), in which there is extra or missing sex chromosome material (either a whole chromosome or a chromosome segment).
The condition in which one chromosome of a pair is missing. In a normally diploid cell it is represented symbolically as 2N-1.
Male germ cells derived from SPERMATOGONIA. The euploid primary spermatocytes undergo MEIOSIS and give rise to the haploid secondary spermatocytes which in turn give rise to SPERMATIDS.
Genes that are located on the X CHROMOSOME.
Short tracts of DNA sequence that are used as landmarks in GENOME mapping. In most instances, 200 to 500 base pairs of sequence define a Sequence Tagged Site (STS) that is operationally unique in the human genome (i.e., can be specifically detected by the polymerase chain reaction in the presence of all other genomic sequences). The overwhelming advantage of STSs over mapping landmarks defined in other ways is that the means of testing for the presence of a particular STS can be completely described as information in a database.
An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.
Genes that influence the PHENOTYPE both in the homozygous and the heterozygous state.
A plant genus of the family POACEAE that is the source of EDIBLE GRAIN. A hybrid with rye (SECALE CEREALE) is called TRITICALE. The seed is ground into FLOUR and used to make BREAD, and is the source of WHEAT GERM AGGLUTININS.
A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Subnormal intellectual functioning which originates during the developmental period. This has multiple potential etiologies, including genetic defects and perinatal insults. Intelligence quotient (IQ) scores are commonly used to determine whether an individual has an intellectual disability. IQ scores between 70 and 79 are in the borderline range. Scores below 67 are in the disabled range. (from Joynt, Clinical Neurology, 1992, Ch55, p28)
The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.
A genotoxicological technique for measuring DNA damage in an individual cell using single-cell gel electrophoresis. Cell DNA fragments assume a "comet with tail" formation on electrophoresis and are detected with an image analysis system. Alkaline assay conditions facilitate sensitive detection of single-strand damage.
An aberrant form of human CHROMOSOME 22 characterized by translocation of the distal end of chromosome 9 from 9q34, to the long arm of chromosome 22 at 22q11. It is present in the bone marrow cells of 80 to 90 per cent of patients with chronic myelocytic leukemia (LEUKEMIA, MYELOGENOUS, CHRONIC, BCR-ABL POSITIVE).
Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.
PHENOTHIAZINES with an amino group at the 3-position that are green crystals or powder. They are used as biological stains.
Structures within the nucleus of archaeal cells consisting of or containing DNA, which carry genetic information essential to the cell.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Overlapping of cloned or sequenced DNA to construct a continuous region of a gene, chromosome or genome.
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.
The degree of replication of the chromosome set in the karyotype.
An autosomal recessive inherited disorder characterized by choreoathetosis beginning in childhood, progressive CEREBELLAR ATAXIA; TELANGIECTASIS of CONJUNCTIVA and SKIN; DYSARTHRIA; B- and T-cell immunodeficiency, and RADIOSENSITIVITY to IONIZING RADIATION. Affected individuals are prone to recurrent sinobronchopulmonary infections, lymphoreticular neoplasms, and other malignancies. Serum ALPHA-FETOPROTEINS are usually elevated. (Menkes, Textbook of Child Neurology, 5th ed, p688) The gene for this disorder (ATM) encodes a cell cycle checkpoint protein kinase and has been mapped to chromosome 11 (11q22-q23).
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The relationships of groups of organisms as reflected by their genetic makeup.
A complex of related glycopeptide antibiotics from Streptomyces verticillus consisting of bleomycin A2 and B2. It inhibits DNA metabolism and is used as an antineoplastic, especially for solid tumors.

Telomere loss in somatic cells of Drosophila causes cell cycle arrest and apoptosis. (1/785)

Checkpoint mechanisms that respond to DNA damage in the mitotic cell cycle are necessary to maintain the fidelity of chromosome transmission. These mechanisms must be able to distinguish the normal telomeres of linear chromosomes from double-strand break damage. However, on several occasions, Drosophila chromosomes that lack their normal telomeric DNA have been recovered, raising the issue of whether Drosophila is able to distinguish telomeric termini from nontelomeric breaks. We used site-specific recombination on a dispensable chromosome to induce the formation of a dicentric chromosome and an acentric, telomere-bearing, chromosome fragment in somatic cells of Drosophila melanogaster. The acentric fragment is lost when cells divide and the dicentric breaks, transmitting a chromosome that has lost a telomere to each daughter cell. In the eye imaginal disc, cells with a newly broken chromosome initially experience mitotic arrest and then undergo apoptosis when cells are induced to divide as the eye differentiates. Therefore, Drosophila cells can detect and respond to a single broken chromosome. It follows that transmissible chromosomes lacking normal telomeric DNA nonetheless must possess functional telomeres. We conclude that Drosophila telomeres can be established and maintained by a mechanism that does not rely on the terminal DNA sequence.  (+info)

Der(22) syndrome and velo-cardio-facial syndrome/DiGeorge syndrome share a 1.5-Mb region of overlap on chromosome 22q11. (2/785)

Derivative 22 (der[22]) syndrome is a rare disorder associated with multiple congenital anomalies, including profound mental retardation, preauricular skin tags or pits, and conotruncal heart defects. It can occur in offspring of carriers of the constitutional t(11;22)(q23;q11) translocation, owing to a 3:1 meiotic malsegregation event resulting in partial trisomy of chromosomes 11 and 22. The trisomic region on chromosome 22 overlaps the region hemizygously deleted in another congenital anomaly disorder, velo-cardio-facial syndrome/DiGeorge syndrome (VCFS/DGS). Most patients with VCFS/DGS have a similar 3-Mb deletion, whereas some have a nested distal deletion endpoint resulting in a 1.5-Mb deletion, and a few rare patients have unique deletions. To define the interval on 22q11 containing the t(11;22) breakpoint, haplotype analysis and FISH mapping were performed for five patients with der(22) syndrome. Analysis of all the patients was consistent with 3:1 meiotic malsegregation in the t(11;22) carrier parent. FISH-mapping studies showed that the t(11;22) breakpoint occurred in the same interval as the 1.5-Mb distal deletion breakpoint for VCFS. The deletion breakpoint of one VCFS patient with an unbalanced t(18;22) translocation also occurred in the same region. Hamster-human somatic hybrid cell lines from a patient with der(22) syndrome and a patient with VCFS showed that the breakpoints occurred in an interval containing low-copy repeats, distal to RANBP1 and proximal to ZNF74. The presence of low-copy repetitive sequences may confer susceptibility to chromosome rearrangements. A 1.5-Mb region of overlap on 22q11 in both syndromes suggests the presence of dosage-dependent genes in this interval.  (+info)

Low-copy repeats mediate the common 3-Mb deletion in patients with velo-cardio-facial syndrome. (3/785)

Velo-cardio-facial syndrome (VCFS) is the most common microdeletion syndrome in humans. It occurs with an estimated frequency of 1 in 4, 000 live births. Most cases occur sporadically, indicating that the deletion is recurrent in the population. More than 90% of patients with VCFS and a 22q11 deletion have a similar 3-Mb hemizygous deletion, suggesting that sequences at the breakpoints confer susceptibility to rearrangements. To define the region containing the chromosome breakpoints, we constructed an 8-kb-resolution physical map. We identified a low-copy repeat in the vicinity of both breakpoints. A set of genetic markers were integrated into the physical map to determine whether the deletions occur within the repeat. Haplotype analysis with genetic markers that flank the repeats showed that most patients with VCFS had deletion breakpoints in the repeat. Within the repeat is a 200-kb duplication of sequences, including a tandem repeat of genes/pseudogenes, surrounding the breakpoints. The genes in the repeat are GGT, BCRL, V7-rel, POM121-like, and GGT-rel. Physical mapping and genomic fingerprint analysis showed that the repeats are virtually identical in the 200-kb region, suggesting that the deletion is mediated by homologous recombination. Examination of two three-generation families showed that meiotic intrachromosomal recombination mediated the deletion.  (+info)

Delineation of the critical deletion region for congenital heart defects, on chromosome 8p23.1. (4/785)

Deletions in the distal region of chromosome 8p (del8p) are associated with congenital heart malformations. Other major manifestations include microcephaly, intrauterine growth retardation, mental retardation, and a characteristic hyperactive, impulsive behavior. We studied genotype-phenotype correlations in nine unrelated patients with a de novo del8p, by using the combination of classic cytogenetics, FISH, and the analysis of polymorphic DNA markers. With the exception of one large terminal deletion, all deletions were interstitial. In five patients, a commonly deleted region of approximately 6 Mb was present, with breakpoints clustering in the same regions. One patient without a heart defect or microcephaly but with mild mental retardation and characteristic behavior had a smaller deletion within this commonly deleted region. Two patients without a heart defect had a more proximal interstitial deletion that did not overlap with the commonly deleted region. Taken together, these data allowed us to define the critical deletion regions for the major features of a del8p.  (+info)

Development and validation of a quantitative polymerase chain reaction assay to evaluate minimal residual disease for T-cell acute lymphoblastic leukemia and follicular lymphoma. (5/785)

The presence of occult disease in cancer patients after therapy is one of the major problems faced by oncologists. For example, although 95% of pediatric T-cell acute lymphoblastic leukemia (T-ALL) patients have a complete therapeutic response to multiagent chemotherapy, half will relapse, indicating that they must have harbored low levels of residual cancer cells at the end of therapy. Sensitive detection assays promise to help identify those patients that carry this minimal residual disease (MRD) and are at risk of relapse. We have developed and validated a quantitative polymerase chain reaction (PCR) assay targeting tumor-specific chromosomal rearrangements, including del(1) involving the tal-1 locus in pediatric T-ALL and t(14;18) involving the bcl-2 locus in follicular lymphoma. This quantitative PCR assay utilizes a synthetic internal calibration standard (ICS) that contains priming sequences identical to those found flanking the chromosomal rearrangement breakpoints. Using this ICS-PCR method, the limits of detection were 5 tumor cells at ratios of 1 tumor cell in 10(5) normal cells and a linear range up to 100% tumor cells. This ICS-PCR method has also performed well in terms of precision and accuracy as indicated by low coefficients of variation, minimal random, proportional, and constant errors, and good clinical sensitivity and specificity characteristics. This technique will allow for the evaluation of parameters such as the rate of therapeutic response and the levels of MRD as predictors of patient outcome.  (+info)

Nonrandom cytogenetic alterations in hepatocellular carcinoma from transgenic mice overexpressing c-Myc and transforming growth factor-alpha in the liver. (6/785)

Identification of specific and primary chromosomal alterations during the course of neoplastic development is an essential part of defining the genetic basis of cancer. We have developed a transgenic mouse model for liver neoplasia in which chromosomal lesions associated with both the initial stages of the neoplastic process and the acquisition of malignancy can be analyzed. Here we analyze chromosomal alterations in 11 hepatocellular carcinomas from the c-myc/TGF-alpha double-transgenic mice by fluorescent in situ hybridization with whole chromosome probes, single-copy genes, and 4'-6-diamidino-2-phenylindole (DAPI-) and G-banded chromosomes and report nonrandom cytogenetic alterations associated with the tumor development. All tumors were aneuploid and exhibited nonrandom structural and numerical alterations. A balanced translocation t(5:6)(G1;F2) was identified by two-color fluorescent in situ hybridization in all tumors, and, using a genomic probe, the c-myc transgene was localized near the breakpoint on derivative chromosome der 6. Partial or complete loss of chromosome 4 was observed in all tumors with nonrandom breakage in band C2. Deletions of chromosome 1 were observed in 80% of the tumors, with the most frequent deletion at the border of bands C4 and C5. An entire copy of chromosome 7 was lost in 80% of the tumors cells. Eighty-five percent of the tumor cells had lost one copy of chromosome 12, and the most common breakpoint on chromosome 12 occurred at band D3 (28%). A copy of chromosome 14 was lost in 72%, and band 14E1 was deleted in 32% of the tumor cells. The X chromosome was lost in the majority of the tumor cells. The most frequent deletion on the X chromosome involved band F1. We have previously shown that breakages of chromosomes 1, 6, 7, and 12 were observed before the appearance of morphologically distinct neoplastic liver lesions in this transgenic mouse model. Thus breakpoints on chromosome 4, 9, 14, and X appear to be later events in this model of liver neoplasia. This is the first study to demonstrate that specific sites of chromosomal breakage observed during a period of chromosomal instability in early stages of carcinogenesis are later involved in stable rearrangements in solid tumors. The identification of the 5;6 translocation in all of the tumors has a special significance, being the first balanced translocation reported in human and mouse hepatocellular carcinoma and having the breakpoint near a tumor susceptibility gene and myc transgene site of integration. Moreover, its early occurrence indicates that this is a primary and relevant alteration to the initiation of the neoplastic process. In addition, the concordance between the breakpoints observed during the early dysplastic stage of hepatocarcinogenesis and the stable deletions of chromosomes 1, 4, 6, 7, 9, and 12 in the tumors provides evidence for preferential site of genetic changes in hepatocarcinogenesis.  (+info)

Increased chromosomal instability in peripheral lymphocytes and risk of human gliomas. (7/785)

Brain tumors exhibit considerable chromosome instability (CIN), suggesting that genetic susceptibility may contribute to brain tumorigenesis. To test this hypothesis, in this pilot study, we examined for CIN in short-term lymphocyte cultures from 25 adult glioma patients and 28 age-, sex- and ethnicity-matched healthy controls (all Caucasian). We evaluated CIN by a multicolor fluorescence in situ hybridization assay using two probes: a classic satellite probe for a large heterochromatin breakage-prone region of chromosome 1 and an alpha satellite probe for a smaller region adjacent to the heterochromatin probe. Our results showed a significant increase in the mean number of spontaneous breaks per 1000 cells in glioma patients (mean +/- SD, 2.4+/-0.8) compared with controls (1.4+/-0.9; P < 0.001). By using the median number of breaks per 1000 cells in the controls as the cutoff value, we observed a crude odds ratio (OR) of 8.5 [95% confidence interval (CI) = 2.05-34.9, P < 0.001] for spontaneous breaks and brain tumor risk. After adjustment for age, sex and smoking status, the adjusted OR was 15.3 (95% CI, 2.71-87.8). A significant increase in cells with chromosome 1 aneuploidy (in the form of hyperdiploidy) (P < 0.001) was also observed in the glioma cases, with an adjusted OR of 6.6 (95% CI = 1.5-30, P < 0.05). These findings suggest that CIN can be detected in the peripheral blood lymphocytes of brain tumor patients and may be a marker for identifying individuals at risk.  (+info)

Rearrangements of chromosome band 1p36 in non-Hodgkin's lymphoma. (8/785)

We studied 850 consecutive cases of histologically ascertained pretreatment non-Hodgkin's lymphoma with cytogenetically abnormal clones. The diagnostic karyotypes revealed that 12% of these cases exhibited structural rearrangements involving chromosome band 1p36. Here, we describe the karyotypes of 53 cases containing a 1p36 rearrangement [often involving translocations of unknown material and presented as add(1)(p36)]. We used fluorescence in situ hybridization to determine the origin of the translocation partners. We report three different recurrent translocations involving 1p36. These include der(1)t(1;1)(p36;q21) (three cases), der(1)t(1;1)(p36;q25) (three cases), and der(1)t(1;9)(p36;q13) (four cases). Using cytogenetic and fluorescence in situ hybridization analyses, we have resolved the translocation partners in 31 cases. Rearrangements of band 1p36 were found among different histopathological subtypes. Alterations of 1p36 never occurred as a sole abnormality, and in 42 of 53 cases, alterations of the band 14q32 were observed. The t(14;18)(q32;q21) translocation was present in 35 cases. The significantly high occurrence of 1p36 breakpoint in structural rearrangements and its involvement in recurrent translocations suggest that the region is bearing gene(s) that are important in lymphomagenesis. Our study also showed that cytogenetically evident deletions were frequent in chromosome 1p, almost always involving the p36 region, whereas duplications were rare and never encompassed the p36 region. Chromosome band 1p36 harbors many candidate tumor suppressor genes, and we propose that one or more of these genes might be deleted or functionally disrupted as a molecular consequence of the rearrangements, thus contributing to lymphomagenesis.  (+info)

When a chromosome breaks, it can lead to genetic instability and potentially contribute to the development of diseases such as cancer. Chromosome breakage can also result in the loss or gain of genetic material, which can further disrupt normal cellular function and increase the risk of disease.

There are several types of chromosome breakage, including:

1. Chromosomal aberrations: These occur when there is a change in the number or structure of the chromosomes, such as an extra copy of a chromosome (aneuploidy) or a break in a chromosome.
2. Genomic instability: This refers to the presence of errors in the genetic material that can lead to changes in the function of cells and tissues.
3. Chromosomal fragile sites: These are specific regions of the chromosomes that are more prone to breakage than other regions.
4. Telomere shortening: Telomeres are the protective caps at the ends of the chromosomes, and their shortening can lead to chromosome breakage and genetic instability.

Chromosome breakage can be detected through cytogenetic analysis, which involves staining the cells with dyes to visualize the chromosomes and look for any abnormalities. The detection of chromosome breakage can help diagnose certain diseases, such as cancer, and can also provide information about the risk of disease progression.

In summary, chromosome breakage is a type of genetic alteration that can occur as a result of various factors, including exposure to radiation or chemicals, errors during cell division, or aging. It can lead to genetic instability and increase the risk of diseases such as cancer. Detection of chromosome breakage through cytogenetic analysis can help diagnose certain diseases and provide information about the risk of disease progression.

There are several types of chromosome fragility, including:

1. Fragile X syndrome: This is the most common form of chromosome fragility and is caused by an expansion of a CGG repeat in the FMR1 gene on the X chromosome. It is associated with intellectual disability, behavioral problems, and physical characteristics such as large ears and long faces.
2. Turner syndrome: This is a condition where one X chromosome is missing or partially deleted, leading to short stature, infertility, and other developmental delays.
3. Klinefelter syndrome: This is a condition where an individual has an extra X chromosome, leading to tall stature, small testes, and infertility.
4. Trisomy 13 and trisomy 18: These are conditions where there is an extra copy of chromosomes 13 or 18, leading to developmental delays and other physical and intellectual disabilities.
5. Chromosome breakage syndromes: These are conditions where there is a defect in the chromosome that increases the risk of breakage during cell division, leading to aneuploidy or structural changes. Examples include ataxia-telangiectasia and Nijmegen breakage syndrome.

Chromosome fragility can be diagnosed through a variety of methods, including karyotyping, fluorescence in situ hybridization (FISH), and array comparative genomic hybridization (aCGH). Treatment for chromosome fragility depends on the specific condition and may include medication, surgery, or other interventions.

There are several types of chromosome aberrations, including:

1. Chromosomal deletions: Loss of a portion of a chromosome.
2. Chromosomal duplications: Extra copies of a chromosome or a portion of a chromosome.
3. Chromosomal translocations: A change in the position of a chromosome or a portion of a chromosome.
4. Chromosomal inversions: A reversal of a segment of a chromosome.
5. Chromosomal amplifications: An increase in the number of copies of a particular chromosome or gene.

Chromosome aberrations can be detected through various techniques, such as karyotyping, fluorescence in situ hybridization (FISH), or array comparative genomic hybridization (aCGH). These tests can help identify changes in the chromosomal makeup of cells and provide information about the underlying genetic causes of disease.

Chromosome aberrations are associated with a wide range of diseases, including:

1. Cancer: Chromosome abnormalities are common in cancer cells and can contribute to the development and progression of cancer.
2. Birth defects: Many birth defects are caused by chromosome abnormalities, such as Down syndrome (trisomy 21), which is caused by an extra copy of chromosome 21.
3. Neurological disorders: Chromosome aberrations have been linked to various neurological disorders, including autism and intellectual disability.
4. Immunodeficiency diseases: Some immunodeficiency diseases, such as X-linked severe combined immunodeficiency (SCID), are caused by chromosome abnormalities.
5. Infectious diseases: Chromosome aberrations can increase the risk of infection with certain viruses, such as human immunodeficiency virus (HIV).
6. Ageing: Chromosome aberrations have been linked to the ageing process and may contribute to the development of age-related diseases.
7. Radiation exposure: Exposure to radiation can cause chromosome abnormalities, which can increase the risk of cancer and other diseases.
8. Genetic disorders: Many genetic disorders are caused by chromosome aberrations, such as Turner syndrome (45,X), which is caused by a missing X chromosome.
9. Rare diseases: Chromosome aberrations can cause rare diseases, such as Klinefelter syndrome (47,XXY), which is caused by an extra copy of the X chromosome.
10. Infertility: Chromosome abnormalities can contribute to infertility in both men and women.

Understanding the causes and consequences of chromosome aberrations is important for developing effective treatments and improving human health.

There are many different types of chromosome disorders, including:

1. Trisomy: This is a condition in which there is an extra copy of a chromosome. For example, Down syndrome is caused by an extra copy of chromosome 21.
2. Monosomy: This is a condition in which there is a missing copy of a chromosome.
3. Turner syndrome: This is a condition in which there is only one X chromosome instead of two.
4. Klinefelter syndrome: This is a condition in which there are three X chromosomes instead of the typical two.
5. Chromosomal translocations: These are abnormalities in which a piece of one chromosome breaks off and attaches to another chromosome.
6. Inversions: These are abnormalities in which a segment of a chromosome is reversed end-to-end.
7. Deletions: These are abnormalities in which a portion of a chromosome is missing.
8. Duplications: These are abnormalities in which there is an extra copy of a segment of a chromosome.

Chromosome disorders can have a wide range of effects on the body, depending on the type and severity of the condition. Some common features of chromosome disorders include developmental delays, intellectual disability, growth problems, and physical abnormalities such as heart defects or facial anomalies.

There is no cure for chromosome disorders, but treatment and support are available to help manage the symptoms and improve the quality of life for individuals with these conditions. Treatment may include medications, therapies, and surgery, as well as support and resources for families and caregivers.

Preventive measures for chromosome disorders are not currently available, but research is ongoing to understand the causes of these conditions and to develop new treatments and interventions. Early detection and diagnosis can help identify chromosome disorders and provide appropriate support and resources for individuals and families.

In conclusion, chromosome disorders are a group of genetic conditions that affect the structure or number of chromosomes in an individual's cells. These conditions can have a wide range of effects on the body, and there is no cure, but treatment and support are available to help manage symptoms and improve quality of life. Early detection and diagnosis are important for identifying chromosome disorders and providing appropriate support and resources for individuals and families.

Some common effects of chromosomal deletions include:

1. Genetic disorders: Chromosomal deletions can lead to a variety of genetic disorders, such as Down syndrome, which is caused by a deletion of a portion of chromosome 21. Other examples include Prader-Willi syndrome (deletion of chromosome 15), and Williams syndrome (deletion of chromosome 7).
2. Birth defects: Chromosomal deletions can increase the risk of birth defects, such as heart defects, cleft palate, and limb abnormalities.
3. Developmental delays: Children with chromosomal deletions may experience developmental delays, learning disabilities, and intellectual disability.
4. Increased cancer risk: Some chromosomal deletions can increase the risk of developing certain types of cancer, such as chronic myelogenous leukemia (CML) and breast cancer.
5. Reproductive problems: Chromosomal deletions can lead to reproductive problems, such as infertility or recurrent miscarriage.

Chromosomal deletions can be diagnosed through a variety of techniques, including karyotyping (examination of the chromosomes), fluorescence in situ hybridization (FISH), and microarray analysis. Treatment options for chromosomal deletions depend on the specific effects of the deletion and may include medication, surgery, or other forms of therapy.

There are currently no cures for Fanconi anemia, but bone marrow transplantation and other supportive therapies can help manage some of the symptoms and improve quality of life. Research into the genetics and molecular biology of Fanconi anemia is ongoing to better understand the disorder and develop new treatments.

Some of the common symptoms of Fanconi anemia include short stature, limb deformities, hearing loss, vision problems, and an increased risk of infections and cancer. Children with Fanconi anemia may also experience developmental delays, learning disabilities, and social and emotional challenges.

The diagnosis of Fanconi anemia is typically made based on a combination of clinical findings, laboratory tests, and genetic analysis. Treatment options for Fanconi anemia depend on the severity of the disorder and may include bone marrow transplantation, blood transfusions, antibiotics, and other supportive therapies.

Fanconi anemia is a rare disorder that affects approximately 1 in 160,000 births worldwide. It is more common in certain populations, such as Ashkenazi Jews and individuals of Spanish descent. Fanconi anemia can be inherited in an autosomal recessive pattern, meaning that a child must inherit two copies of the mutated gene (one from each parent) to develop the disorder.

Overall, Fanconi anemia is a complex and rare genetic disorder that requires specialized medical care and ongoing research to better understand its causes and develop effective treatments. With appropriate management and supportive therapies, individuals with Fanconi anemia can lead fulfilling lives despite the challenges associated with the disorder.

There are several types of aneuploidy, including:

1. Trisomy: This is the presence of an extra copy of a chromosome. For example, Down syndrome is caused by an extra copy of chromosome 21 (trisomy 21).
2. Monosomy: This is the absence of a chromosome.
3. Mosaicism: This is the presence of both normal and abnormal cells in the body.
4. Uniparental disomy: This is the presence of two copies of a chromosome from one parent, rather than one copy each from both parents.

Aneuploidy can occur due to various factors such as errors during cell division, exposure to certain chemicals or radiation, or inheritance of an abnormal number of chromosomes from one's parents. The risk of aneuploidy increases with age, especially for women over the age of 35, as their eggs are more prone to errors during meiosis (the process by which egg cells are produced).

Aneuploidy can be diagnosed through various methods such as karyotyping (examining chromosomes under a microscope), fluorescence in situ hybridization (FISH) or quantitative PCR. Treatment for aneuploidy depends on the underlying cause and the specific health problems it has caused. In some cases, treatment may involve managing symptoms, while in others, it may involve correcting the genetic abnormality itself.

In summary, aneuploidy is a condition where there is an abnormal number of chromosomes present in a cell, which can lead to various developmental and health problems. It can occur due to various factors and can be diagnosed through different methods. Treatment depends on the underlying cause and the specific health problems it has caused.

The presence of chromosome-defective micronuclei in cells can be an indication of genetic damage and may be used as a diagnostic marker for certain diseases or conditions, such as cancer or exposure to toxic substances. The frequency and distribution of these structures within a cell population can also provide information about the type and severity of genetic damage present.

In contrast to other types of micronuclei, which are typically smaller and less complex, chromosome-defective micronuclei are larger and more irregular in shape, and may contain fragmented or abnormal chromatin material. They can also be distinguished from other types of micronuclei by their specific staining properties and the presence of certain structural features, such as the presence of nucleoli or the absence of a membrane boundary.

Overall, the study of chromosome-defective micronuclei is an important tool for understanding the mechanisms of genetic damage and disease, and may have practical applications in fields such as cancer diagnosis and environmental health assessment.

https://www.medicinenet.com › Medical Dictionary › G

A genetic translocation is a change in the number or arrangement of the chromosomes in a cell. It occurs when a portion of one chromosome breaks off and attaches to another chromosome. This can result in a gain or loss of genetic material, which can have significant effects on the individual.

Genetic Translocation | Definition & Facts | Britannica
https://www.britannica.com › science › Genetic-tr...

Genetic translocation, also called chromosomal translocation, a type of chromosomal aberration in which a portion of one chromosome breaks off and attaches to another chromosome. This can result in a gain or loss of genetic material. Genetic translocations are often found in cancer cells and may play a role in the development and progression of cancer.

Translocation, Genetic | health Encyclopedia - UPMC
https://www.upmc.com › health-library › gene...

A genetic translocation is a change in the number or arrangement of the chromosomes in a cell. It occurs when a portion of one chromosome breaks off and attaches to another chromosome. This can result in a gain or loss of genetic material, which can have significant effects on the individual.

Genetic Translocation | Genetics Home Reference - NIH
https://ghr.nlm.nih.gov › condition › ge...

A genetic translocation is a change in the number or arrangement of the chromosomes in a cell. It occurs when a portion of one chromosome breaks off and attaches to another chromosome. This can result in a gain or loss of genetic material, which can have significant effects on the individual.

In conclusion, Genetic Translocation is an abnormality in the number or arrangement of chromosomes in a cell. It occurs when a portion of one chromosome breaks off and attaches to another chromosome, resulting in a gain or loss of genetic material that can have significant effects on the individual.

Causes of Chromosomal Instability:

1. Genetic mutations: Mutations in genes that regulate the cell cycle or chromosome segregation can lead to CIN.
2. Environmental factors: Exposure to certain environmental agents such as radiation and certain chemicals can increase the risk of developing CIN.
3. Errors during DNA replication: Mistakes during DNA replication can also lead to CIN.

Types of Chromosomal Instability:

1. Aneuploidy: Cells with an abnormal number of chromosomes, either more or fewer than the normal diploid number (46 in humans).
2. Structural changes: Deletions, duplications, inversions, translocations, and other structural changes can occur in the chromosomes.
3. Unstable chromosome structures: Chromosomes with abnormal shapes or structures, such as telomere shortening, centromere instability, or chromosome breaks, can also lead to CIN.

Effects of Chromosomal Instability:

1. Cancer: CIN can increase the risk of developing cancer by disrupting normal cellular processes and leading to genetic mutations.
2. Aging: CIN can contribute to aging by shortening telomeres, which are the protective caps at the ends of chromosomes that help maintain their stability.
3. Neurodegenerative diseases: CIN has been implicated in the development of certain neurodegenerative diseases such as Alzheimer's and Parkinson's.
4. Infertility: CIN can lead to infertility by disrupting normal meiotic recombination and chromosome segregation during gametogenesis.

Detection and Diagnosis of Chromosomal Instability:

1. Karyotyping: This is a technique used to visualize the entire set of chromosomes in a cell. It can help identify structural abnormalities such as deletions, duplications, or translocations.
2. Fluorescence in situ hybridization (FISH): This technique uses fluorescent probes to detect specific DNA sequences or proteins on chromosomes. It can help identify changes in chromosome structure or number.
3. Array comparative genomic hybridization (aCGH): This technique compares the genetic material of a sample to a reference genome to identify copy number changes.
4. Next-generation sequencing (NGS): This technique can identify point mutations and other genetic changes in DNA.

Treatment and Management of Chromosomal Instability:

1. Cancer treatment: Depending on the type and stage of cancer, treatments such as chemotherapy, radiation therapy, or surgery may be used to eliminate cancer cells with CIN.
2. Prenatal testing: Pregnant women with a family history of CIN can undergo prenatal testing to detect chromosomal abnormalities in their fetuses.
3. Genetic counseling: Individuals with a family history of CIN can consult with a genetic counselor to discuss risk factors and potential testing options.
4. Lifestyle modifications: Making healthy lifestyle choices such as maintaining a balanced diet, exercising regularly, and not smoking can help reduce the risk of developing cancer and other diseases associated with CIN.

In conclusion, chromosomal instability is a common feature of many human diseases, including cancer, and can be caused by a variety of factors. The diagnosis and management of CIN require a multidisciplinary approach that includes cytogenetic analysis, molecular diagnostics, and clinical evaluation. Understanding the causes and consequences of CIN is crucial for developing effective therapies and improving patient outcomes.

Inversions are classified based on their location along the chromosome:

* Interstitial inversion: A segment of DNA is reversed within a larger gene or group of genes.
* Pericentric inversion: A segment of DNA is reversed near the centromere, the region of the chromosome where the sister chromatids are most closely attached.

Chromosome inversions can be detected through cytogenetic analysis, which allows visualization of the chromosomes and their structure. They can also be identified using molecular genetic techniques such as PCR (polymerase chain reaction) or array comparative genomic hybridization (aCGH).

Chromosome inversions are relatively rare in the general population, but they have been associated with various developmental disorders and an increased risk of certain diseases. For example, individuals with an inversion on chromosome 8p have an increased risk of developing cancer, while those with an inversion on chromosome 9q have a higher risk of developing neurological disorders.

Inversions can be inherited from one or both parents, and they can also occur spontaneously as a result of errors during DNA replication or repair. In some cases, inversions may be associated with other genetic abnormalities, such as translocations or deletions.

Overall, chromosome inversions are an important aspect of human genetics and can provide valuable insights into the mechanisms underlying developmental disorders and disease susceptibility.

Ring chromosomes are relatively rare, occurring in about 1 in every 10,000 to 20,000 births. They can be caused by a variety of factors, including genetic mutations, errors during cell division, or exposure to certain chemicals or radiation.

Ring chromosomes can affect anyone, regardless of age or gender. However, they are more common in certain populations, such as people with a family history of the condition or those who have certain medical conditions like Down syndrome or Turner syndrome.

The symptoms of ring chromosomes can vary widely and may include:

* Delayed growth and development
* Intellectual disability or learning difficulties
* Speech and language problems
* Vision and hearing impairments
* Heart defects
* Bone and joint problems
* Increased risk of infections and other health problems

Ring chromosomes can be diagnosed through a variety of tests, including karyotyping, fluorescence in situ hybridization (FISH), and microarray analysis. Treatment for the condition typically focuses on managing any associated health problems and may include medication, surgery, or other interventions.

In some cases, ring chromosomes can be inherited from one's parents. However, many cases are not inherited and occur spontaneously due to a genetic mutation. In these cases, the risk of recurrence in future pregnancies is generally low.

Overall, ring chromosomes are a complex and relatively rare chromosomal abnormality that can have a significant impact on an individual's health and development. With proper diagnosis and treatment, many people with ring chromosomes can lead fulfilling lives, but it is important to work closely with medical professionals to manage any associated health problems.

Some examples of multiple abnormalities include:

1. Multiple chronic conditions: An individual may have multiple chronic conditions such as diabetes, hypertension, arthritis, and heart disease, which can affect their quality of life and increase their risk of complications.
2. Congenital anomalies: Some individuals may be born with multiple physical abnormalities or birth defects, such as heart defects, limb abnormalities, or facial deformities.
3. Mental health disorders: Individuals may experience multiple mental health disorders, such as depression, anxiety, and bipolar disorder, which can impact their cognitive functioning and daily life.
4. Neurological conditions: Some individuals may have multiple neurological conditions, such as epilepsy, Parkinson's disease, and stroke, which can affect their cognitive and physical functioning.
5. Genetic disorders: Individuals with genetic disorders, such as Down syndrome or Turner syndrome, may experience a range of physical and developmental abnormalities.

The term "multiple abnormalities" is often used in medical research and clinical practice to describe individuals who have complex health needs and require comprehensive care. It is important for healthcare providers to recognize and address the multiple needs of these individuals to improve their overall health outcomes.

Trisomy is caused by an extra copy of a chromosome, which can be due to one of three mechanisms:

1. Trisomy 21 (Down syndrome): This is the most common type of trisomy and occurs when there is an extra copy of chromosome 21. It is estimated to occur in about 1 in every 700 births.
2. Trisomy 13 (Patau syndrome): This type of trisomy occurs when there is an extra copy of chromosome 13. It is estimated to occur in about 1 in every 10,000 births.
3. Trisomy 18 (Edwards syndrome): This type of trisomy occurs when there is an extra copy of chromosome 18. It is estimated to occur in about 1 in every 2,500 births.

The symptoms of trisomy can vary depending on the type of trisomy and the severity of the condition. Some common symptoms include:

* Delayed physical growth and development
* Intellectual disability
* Distinctive facial features, such as a flat nose, small ears, and a wide, short face
* Heart defects
* Vision and hearing problems
* GI issues
* Increased risk of infection

Trisomy can be diagnosed before birth through prenatal testing, such as chorionic villus sampling (CVS) or amniocentesis. After birth, it can be diagnosed through a blood test or by analyzing the child's DNA.

There is no cure for trisomy, but treatment and support are available to help manage the symptoms and improve the quality of life for individuals with the condition. This may include physical therapy, speech therapy, occupational therapy, and medication to manage heart defects or other medical issues. In some cases, surgery may be necessary to correct physical abnormalities.

The prognosis for trisomy varies depending on the type of trisomy and the severity of the condition. Some forms of trisomy are more severe and can be life-threatening, while others may have a more mild impact on the individual's quality of life. With appropriate medical care and support, many individuals with trisomy can lead fulfilling lives.

In summary, trisomy is a genetic condition that occurs when there is an extra copy of a chromosome. It can cause a range of symptoms and can be diagnosed before or after birth. While there is no cure for trisomy, treatment and support are available to help manage the symptoms and improve the quality of life for individuals with the condition.

There are several types of genetic nondisjunction, including:

1. Robertsonian translocation: This type of nondisjunction involves the exchange of genetic material between two chromosomes, resulting in a mixture of genetic information that can lead to developmental abnormalities.
2. Turner syndrome: This is a rare condition that occurs when one X chromosome is missing or partially present, leading to physical and developmental abnormalities in females.
3. Klinefelter syndrome: This condition occurs when an extra X chromosome is present, leading to physical and developmental abnormalities in males.
4. Trisomy 13: This condition occurs when there are three copies of chromosome 13, leading to severe developmental and physical abnormalities.
5. Trisomy 18: This condition occurs when there are three copies of chromosome 18, leading to severe developmental and physical abnormalities.

Genetic nondisjunction can be caused by various factors, including genetic mutations, errors during meiosis, or exposure to certain chemicals or radiation. It can be diagnosed through cytogenetic analysis, which involves studying the chromosomes of cells to identify any abnormalities.

Treatment for genetic nondisjunction depends on the specific type and severity of the condition. In some cases, no treatment is necessary, while in others, medication or surgery may be recommended. Prenatal testing can also be done to detect genetic nondisjunction before birth.

In summary, genetic nondisjunction is a chromosomal abnormality that occurs during meiosis and can lead to developmental and physical abnormalities. It can be caused by various factors and diagnosed through cytogenetic analysis. Treatment depends on the specific type and severity of the condition, and prenatal testing is available to detect genetic nondisjunction before birth.

The symptoms of chromosome duplication vary depending on the location and number of extra chromosomes present. Some common symptoms include:

* Delayed development and growth
* Intellectual disability
* Speech and language delays
* Physical abnormalities, such as heart defects or facial dysmorphism
* Increased risk of developing certain health problems, such as autism or epilepsy

Chromosome duplication can be diagnosed through a blood test or by analyzing cells from the body. Treatment is based on the specific symptoms and may include speech therapy, physical therapy, medication, or surgery.

Prognosis for individuals with chromosome duplication varies depending on the location and number of extra chromosomes present, as well as the presence of any other genetic conditions. Some individuals with chromosome duplication may have a good prognosis and lead normal lives, while others may experience significant health problems and developmental delays.

In some cases, chromosome duplication can be inherited from one or both parents, who may be carriers of the condition but do not exhibit any symptoms themselves. In other cases, chromosome duplication can occur spontaneously due to a mistake during cell division.

There is currently no cure for chromosome duplication, but early diagnosis and appropriate interventions can help manage symptoms and improve outcomes for affected individuals.

Examples of syndromes include:

1. Down syndrome: A genetic disorder caused by an extra copy of chromosome 21 that affects intellectual and physical development.
2. Turner syndrome: A genetic disorder caused by a missing or partially deleted X chromosome that affects physical growth and development in females.
3. Marfan syndrome: A genetic disorder affecting the body's connective tissue, causing tall stature, long limbs, and cardiovascular problems.
4. Alzheimer's disease: A neurodegenerative disorder characterized by memory loss, confusion, and changes in personality and behavior.
5. Parkinson's disease: A neurological disorder characterized by tremors, rigidity, and difficulty with movement.
6. Klinefelter syndrome: A genetic disorder caused by an extra X chromosome in males, leading to infertility and other physical characteristics.
7. Williams syndrome: A rare genetic disorder caused by a deletion of genetic material on chromosome 7, characterized by cardiovascular problems, developmental delays, and a distinctive facial appearance.
8. Fragile X syndrome: The most common form of inherited intellectual disability, caused by an expansion of a specific gene on the X chromosome.
9. Prader-Willi syndrome: A genetic disorder caused by a defect in the hypothalamus, leading to problems with appetite regulation and obesity.
10. Sjogren's syndrome: An autoimmune disorder that affects the glands that produce tears and saliva, causing dry eyes and mouth.

Syndromes can be diagnosed through a combination of physical examination, medical history, laboratory tests, and imaging studies. Treatment for a syndrome depends on the underlying cause and the specific symptoms and signs presented by the patient.

Polyploidy is a condition where an organism has more than two sets of chromosomes, which are the thread-like structures that carry genetic information. It can occur in both plants and animals, although it is relatively rare in most species. In humans, polyploidy is extremely rare and usually occurs as a result of errors during cell division or abnormal fertilization.

In medicine, polyploidy is often used to describe certain types of cancer, such as breast cancer or colon cancer, that have extra sets of chromosomes. This can lead to the development of more aggressive and difficult-to-treat tumors.

However, not all cases of polyploidy are cancerous. Some individuals with Down syndrome, for example, have an extra copy of chromosome 21, which is a non-cancerous form of polyploidy. Additionally, some people may be born with extra copies of certain genes or chromosomal regions due to errors during embryonic development, which can lead to various health problems but are not cancerous.

Overall, the term "polyploidy" in medicine is used to describe any condition where an organism has more than two sets of chromosomes, regardless of whether it is cancerous or non-cancerous.

Explanation: Genetic predisposition to disease is influenced by multiple factors, including the presence of inherited genetic mutations or variations, environmental factors, and lifestyle choices. The likelihood of developing a particular disease can be increased by inherited genetic mutations that affect the functioning of specific genes or biological pathways. For example, inherited mutations in the BRCA1 and BRCA2 genes increase the risk of developing breast and ovarian cancer.

The expression of genetic predisposition to disease can vary widely, and not all individuals with a genetic predisposition will develop the disease. Additionally, many factors can influence the likelihood of developing a particular disease, such as environmental exposures, lifestyle choices, and other health conditions.

Inheritance patterns: Genetic predisposition to disease can be inherited in an autosomal dominant, autosomal recessive, or multifactorial pattern, depending on the specific disease and the genetic mutations involved. Autosomal dominant inheritance means that a single copy of the mutated gene is enough to cause the disease, while autosomal recessive inheritance requires two copies of the mutated gene. Multifactorial inheritance involves multiple genes and environmental factors contributing to the development of the disease.

Examples of diseases with a known genetic predisposition:

1. Huntington's disease: An autosomal dominant disorder caused by an expansion of a CAG repeat in the Huntingtin gene, leading to progressive neurodegeneration and cognitive decline.
2. Cystic fibrosis: An autosomal recessive disorder caused by mutations in the CFTR gene, leading to respiratory and digestive problems.
3. BRCA1/2-related breast and ovarian cancer: An inherited increased risk of developing breast and ovarian cancer due to mutations in the BRCA1 or BRCA2 genes.
4. Sickle cell anemia: An autosomal recessive disorder caused by a point mutation in the HBB gene, leading to defective hemoglobin production and red blood cell sickling.
5. Type 1 diabetes: An autoimmune disease caused by a combination of genetic and environmental factors, including multiple genes in the HLA complex.

Understanding the genetic basis of disease can help with early detection, prevention, and treatment. For example, genetic testing can identify individuals who are at risk for certain diseases, allowing for earlier intervention and preventive measures. Additionally, understanding the genetic basis of a disease can inform the development of targeted therapies and personalized medicine."


There are several types of sex chromosome disorders, including:

1. Turner Syndrome: A condition that occurs in females who have only one X chromosome instead of two. This can lead to short stature, infertility, and other health problems.
2. Klinefelter Syndrome: A condition that occurs in males who have an extra X chromosome (XXY). This can lead to tall stature, breast enlargement, and infertility.
3. XXY Syndrome: A condition that occurs in individuals with two X chromosomes and one Y chromosome. This can lead to tall stature, breast enlargement, and fertility problems.
4. XYY Syndrome: A condition that occurs in individuals with an extra Y chromosome (XYY). This can lead to taller stature and fertility problems.
5. Mosaicism: A condition where there is a mixture of normal and abnormal cells in the body, often due to a genetic mutation that occurred during embryonic development.
6. Y chromosome variants: These are variations in the Y chromosome that can affect male fertility or increase the risk of certain health problems.
7. Uniparental disomy: A condition where an individual has two copies of one or more chromosomes, either due to a genetic mutation or because of a mistake during cell division.
8. Structural variations: These are changes in the structure of the sex chromosomes, such as deletions, duplications, or translocations, which can affect gene expression and increase the risk of certain health problems.

Sex chromosome disorders can be diagnosed through chromosomal analysis, which involves analyzing a person's cells to determine their sex chromosome makeup. Treatment for these disorders varies depending on the specific condition and may include hormone therapy, surgery, or other medical interventions.

Monosomy refers to a condition where an individual has only one copy of a particular chromosome, instead of the usual two copies present in every cell of the body. This can occur due to various genetic or environmental factors and can lead to developmental delays, intellectual disability, and physical abnormalities.

Other Defination:
Monosomy can also refer to the absence of a specific chromosome or part of a chromosome. For example, monosomy 21 is the condition where an individual has only one copy of chromosome 21, which is the chromosome responsible for Down syndrome. Similarly, monosomy 8p is the condition where there is a loss of a portion of chromosome 8p.

Synonyms:
Monosomy is also known as single chromosome deletion or single chromosome monosomy.

Antonyms:
Polysomy, which refers to the presence of extra copies of a particular chromosome, is the antonym of monosomy.

In Medical Terminology:
Monosomy is a genetic term that is used to describe a condition where there is only one copy of a particular chromosome present in an individual's cells, instead of the usual two copies. This can occur due to various factors such as errors during cell division or exposure to certain chemicals or viruses. Monosomy can lead to a range of developmental delays and physical abnormalities, depending on the location and extent of the missing chromosome material.

In Plain English:
Monosomy is a condition where a person has only one copy of a particular chromosome instead of two copies. This can cause developmental delays and physical abnormalities, and can be caused by genetic or environmental factors. It's important to note that monosomy can occur on any chromosome, but some specific types of monosomy are more common and well-known than others. For example, Down syndrome is a type of monosomy that occurs when there is an extra copy of chromosome 21.

There are several types of genomic instability, including:

1. Chromosomal instability (CIN): This refers to changes in the number or structure of chromosomes, such as aneuploidy (having an abnormal number of chromosomes) or translocations (the movement of genetic material between chromosomes).
2. Point mutations: These are changes in a single base pair in the DNA sequence.
3. Insertions and deletions: These are changes in the number of base pairs in the DNA sequence, resulting in the insertion or deletion of one or more base pairs.
4. Genomic rearrangements: These are changes in the structure of the genome, such as chromosomal breaks and reunions, or the movement of genetic material between chromosomes.

Genomic instability can arise from a variety of sources, including environmental factors, errors during DNA replication and repair, and genetic mutations. It is often associated with cancer, as cancer cells have high levels of genomic instability, which can lead to the development of resistance to chemotherapy and radiation therapy.

Research into genomic instability has led to a greater understanding of the mechanisms underlying cancer and other diseases, and has also spurred the development of new therapeutic strategies, such as targeted therapies and immunotherapies.

In summary, genomic instability is a key feature of cancer cells and is associated with various diseases, including cancer, neurodegenerative disorders, and aging. It can arise from a variety of sources and is the subject of ongoing research in the field of molecular biology.

There are various causes of intellectual disability, including:

1. Genetic disorders, such as Down syndrome, Fragile X syndrome, and Turner syndrome.
2. Congenital conditions, such as microcephaly and hydrocephalus.
3. Brain injuries, such as traumatic brain injury or hypoxic-ischemic injury.
4. Infections, such as meningitis or encephalitis.
5. Nutritional deficiencies, such as iron deficiency or iodine deficiency.

Intellectual disability can result in a range of cognitive and functional impairments, including:

1. Delayed language development and difficulty with communication.
2. Difficulty with social interactions and adapting to new situations.
3. Limited problem-solving skills and difficulty with abstract thinking.
4. Slow learning and memory difficulties.
5. Difficulty with fine motor skills and coordination.

There is no cure for intellectual disability, but early identification and intervention can significantly improve outcomes. Treatment options may include:

1. Special education programs tailored to the individual's needs.
2. Behavioral therapies, such as applied behavior analysis (ABA) and positive behavior support (PBS).
3. Speech and language therapy.
4. Occupational therapy to improve daily living skills.
5. Medications to manage associated behaviors or symptoms.

It is essential to recognize that intellectual disability is a lifelong condition, but with appropriate support and resources, individuals with ID can lead fulfilling lives and reach their full potential.

Synonyms: BCR-ABL fusion gene, t(9;22)(q34;q11), p210 protein, bcr-abl fusion transcript, breakpoint cluster region (BCR) - Abelson tyrosine kinase (ABLE) fusion gene.

Word Origin: Named after the city of Philadelphia, where it was first described in 1960.

The hallmark symptoms of AT are:

1. Ataxia: difficulty with coordination, balance, and gait.
2. Telangiectasias: small, red blood vessels visible on the skin, particularly on the face, neck, and arms.
3. Ocular telangiectasias: small, red blood vessels visible in the eyes.
4. Cognitive decline: difficulty with memory, learning, and concentration.
5. Seizures: episodes of abnormal electrical activity in the brain.
6. Increased risk of cancer: particularly lymphoma, myeloid leukemia, and breast cancer.

The exact cause of AT is not yet fully understood, but it is thought to be due to mutations in the ATM gene, which is involved in DNA damage response and repair. There is currently no cure for AT, but various treatments are available to manage its symptoms and prevent complications. These may include:

1. Physical therapy: to improve coordination and balance.
2. Occupational therapy: to assist with daily activities and fine motor skills.
3. Speech therapy: to improve communication and swallowing difficulties.
4. Medications: to control seizures, tremors, and other symptoms.
5. Cancer screening: regular monitoring for the development of cancer.

AT is a rare disorder, and it is estimated that only about 1 in 40,000 to 1 in 100,000 individuals are affected worldwide. It is important for healthcare providers to be aware of AT and its symptoms, as early diagnosis and intervention can improve outcomes for patients with this condition.

In mice models, mutations in the Nbs1 subunit of MRN alone (producing the phenotypic analog of Nijmegen Breakage Syndrome in ... Telomeres maintain the integrity of the ends of linear chromosomes during replication and protect them from being recognized as ... Williams, BR; Mirzoeva, OK; Morgan, WF; Lin, J; Dunnick, W; Petrini, JH (16 April 2002). "A murine model of Nijmegen breakage ... Varon R, Demuth I, Chrzanowska KH (1993). "Nijmegen Breakage Syndrome". GeneReviews. PMID 20301355. Taylor AM, Rothblum-Oviatt ...
These enzymes have several functions: to remove DNA supercoils during transcription and DNA replication; for strand breakage ... separating the DNA of daughter chromosomes after DNA replication, and relax DNA. ... during recombination; for chromosome condensation; and to disentangle intertwined DNA during mitosis. This domain assumes a ...
... a chromosome with two centromeres. When dicentric chromosomes form, a series of events can occur called a breakage-fusion- ... As chromosome instability refers to the rate that chromosomes or large portions of chromosomes are changed, there should be ... It can occur due to loss of a whole chromosome, gain of a whole chromosome or rearrangement of partial chromosomes known as ... Since human chromosomes contain repetitive DNA sections, broken DNA segments from one chromosome can combine with similar ...
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Additionally, illegitimate recombinations may also result in dicentric chromosomes lead to chromosome breakage during anaphase ... Since the chromosomes may differ in genetic structure and content, segments of the chromosome may be shuffled around resulting ... The resolution of these structures results in chromosome breakage, rearrangement, and gamete infertility. Diploidization is ... Maintain intra-genomic chromosome pairing at meiosis Chromosome pairing during meiosis is a significant challenge for ...
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NBS is caused by a mutation in the NBS1 gene, located at human chromosome 8q21. The disease is inherited in an autosomal ... "Nijmegen breakage syndrome. The International Nijmegen Breakage Syndrome Study Group". Arch Dis Child. 82 (5): 400-6. 2000. doi ... Group, The International Nijmegen Breakage Syndrome Study (2000-05-01). "Nijmegen breakage syndrome". Archives of Disease in ... Nijmegen breakage syndrome (NBS) is a rare autosomal recessive congenital disorder causing chromosomal instability, probably as ...
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McClintock observed the breakage and fusion of chromosomes in irradiated maize cells. She was also able to show that, in some ... Through her work with X-ray-mutagenized maize, she identified ring chromosomes, which form when the ends of a single chromosome ... By studying the morphology of the chromosomes, McClintock was able to link specific chromosome groups of traits that were ... spontaneous chromosome breakage occurred in the cells of the endosperm. Over the course of mitosis, she observed that the ends ...
"Nondisjunction of a single chromosome leads to breakage and activation of DNA damage checkpoint in G2". PLOS Genetics. 8 (2): ... or if the normal number of chromosomes is restored via duplication of the single monosomic chromosome ("chromosome rescue"). ... Gaining a single chromosome, in which the daughter cell(s) with the defect will have one chromosome in addition to its pairs is ... The extra Y chromosome is usually a result of nondisjunction during paternal meiosis II. Trisomy X is a form of sex chromosome ...
AML-M4 with an inversion of chromosome 16 is caused by breakage and rearrangement within itself. Criteria for AMML is confirmed ... AML with a translocation or inversion is seen in different chromosomes. Specifically, AML with inversion in chromosome 16 also ... This type of arrest is still under study but in most cases, a gene inactivation or activation has occurred due to chromosome ...
"Regulation of endonuclease activity by proteolysis prevents breakage of unmodified bacterial chromosomes by type I restriction ...
Bile acids cause DNA damage, including oxidative DNA damage, double-strand DNA breaks, aneuploidy and chromosome breakage. High ... suggesting that the purpose of the delay is to give the cell time to repair damaged chromosomes before continuing with the cell ... chromosome loss by replisome binding, replication stalling by transcription factors. The DDP human homologs are over- ... Chromosome Research. 27 (4): 345-364. doi:10.1007/s10577-019-09617-x. ISSN 0967-3849. PMC 7934912. PMID 31707536. Gasior, ...
In 1999, he began doctoral studies researching chromosome breakage syndrome, fanconi anemia, gene mutations, and acute myeloid ...
... and there are increases in chromosome breakage and rearrangements compared to persons who do not have Bloom's syndrome. Direct ... Other chromosome manifestations include chromatid breaks and gaps, telomere associations, and fragmented chromosomes. The hyper ... the chromosomes are duplicated so that each new cell will get a complete set of chromosomes. The duplication process is called ... At the level of the chromosomes, the rate of sister chromatid exchange in Bloom's syndrome is approximately 10 fold higher than ...
... producing translocation and deletion of part of a chromosome. Alkylating agents like mustard gas may also cause breakages in ... While changes to the chromosome caused by X-ray and mustard gas were readily observable to early researchers, other changes to ... Muller observed a number of chromosome rearrangements in his experiments, and suggested mutation as a cause of cancer. The ... Double-stranded breakages are especially damaging and hard to repair, ...
CAD leads to the initiation of the DNA strand breakage, which occurs during terminal differentiation of some cell, such as ... Portal: Biology (Articles with short description, Short description matches Wikidata, Genes on human chromosome 1, Apoptosis, ...
The affected hairs are brittle and breakage is common, resulting in short hairs. Migratory lesions of ichthyosis linearis ... "Localization of the Netherton syndrome gene to chromosome 5q32, by linkage analysis and homozygosity mapping". The American ...
Mouse cells deficient for maturation of prelamin A show increased DNA damage and chromosome aberrations and are more sensitive ... These include ataxia-telangiectasia, Nijmegen breakage syndrome, some subgroups of xeroderma pigmentosum, trichothiodystrophy, ... and thus can be correctly repaired using the complementary undamaged sequence in a homologous chromosome if it is available for ...
Telomeres protect the end of the chromosome from DNA damage or from fusion with neighbouring chromosomes. The fruit fly ... Fanconi anemia and Nijmegen breakage syndrome are associated with short telomeres. However, the genes that have mutated in ... Exposed chromosome ends are interpreted as double-stranded breaks (DSB) in DNA; such damage is usually repaired by reattaching ... Cri du chat syndrome (CdCS) is a complex disorder involving the loss of the distal portion of the short arm of chromosome 5. ...
Combined cytological and autoradiographic analyses of meiosis showed that crossing over is achieved by breakage and exchange of ... and it is well removed from premeiotic chromosome duplication. "Search". Eades, D.C.; Otte, D.; Cigliano, M.M.; Braun, H. " ...
Dicentric chromosome) will result in chromosome breakage during mitosis. In some unusual cases human neocentromeres have been ... Chromosome-breaking events can also generate acentric chromosomes or acentric fragments. A dicentric chromosome is an abnormal ... The monocentric chromosome is a chromosome that has only one centromere in a chromosome and forms a narrow constriction. ... but reside closer to the end of the chromosomes. An acentric chromosome is fragment of a chromosome that lacks a centromere. ...
Long had an extra X chromosome. Speck was erroneously reported to have an extra Y chromosome; in fact, his karyotype was ... The term "fracture" is defined as a small breakage of the personality which is often not visible to the outside world and is ... 1979). Sex chromosome aneuploidy: prospective studies on children. Birth defects original article series 15 (1). New York: Alan ... 1982). Children with sex chromosome aneuploidy: follow-up studies. Birth defects original article series 18 (4). New York: Alan ...
Eastmond, D.A.; Rupa, DS; Hasegawa, LS (2000). "Detection of hyperdiploidy and chromosome breakage in interphase human ... which maintains chromosome structure), disruption of microtubules (which maintains cellular structure and organization), ...
When the chromosome is replicated, this gives rise to one daughter chromosome that is heavily methylated downstream of the ... Such direct reversal mechanisms are specific to the type of damage incurred and do not involve breakage of the phosphodiester ... All DNA damage response requires either ATM or ATR because they have the ability to bind to the chromosomes at the site of DNA ... This pathway allows a damaged chromosome to be repaired using a sister chromatid (available in G2 after DNA replication) or a ...
Listed below are some specific tasks this method can carry out: Targeted gene mutation Gene therapy Creating chromosome ... and thus avoids the random insertion and deletions associated with DNA strand breakage. It is only appropriate for precise ... This method uses pseudo-complementary peptide nucleic acid (pcPNA), for identifying cleavage site within the chromosome. Once ...
During metaphase, the chromosomes line up using the spindle apparatus in the middle of the cell along the equatorial plate. The ... The breakage is formed by microtubules and the resealing is negated by Calcium dependent exocytosis using Golgi vesicles. In ... Prophase is the initial phase when spindle fibers appear that function to move the chromosomes toward opposite poles. This ... chromosomes move to opposite poles during anaphase and remain attached to the spindle fibers by their centromeres. Animal cell ...
Individuals with the following DNA damage response disorders exhibit microcephaly: Nijmegen breakage syndrome, ATR-Seckel ... balanced rearrangements and ring chromosome) Syndromes Chromosomal Poland syndrome Down syndrome Edward syndrome Patau syndrome ... Nijmegen breakage syndrome X-linked lissencephaly with abnormal genitalia Aicardi-Goutières syndrome Ataxia telangiectasia ...
RHO Nijmegen breakage syndrome; 251260; NBS1 Nijmegen breakage syndrome-like disorder; 613078; RAD50 Nonaka myopathy; 605820; ... CHM Chromosome 22q13.3 deletion syndrome; 606232; SHANK3 Chromosome 5q14.3 deletion syndrome; 613443; MEF2C Chrondrodysplasia, ... LHCGR Premature chromosome condensation with microcephaly and mental retardation; 606858; MCPH1 Premature ovarian failure 2B; ... CYP2C9 Warsaw breakage syndrome; 613398; DDX11 Watson syndrome; 193520; NF1 Weaver syndrome; 277590; NSD1 Weill-Marchesani ...
In humans, the gene FANCA is 79 kilobases (kb) in length, and is located on chromosome 16 (16q24.3). The FANCA protein is ... The primary diagnostic test for Fanconi anaemia is based on the increased chromosomal breakage seen in afflicted cells after ... FANCA proteins are involved in inter-strand DNA cross-link repair and in the maintenance of normal chromosome stability that ... This is the stage when chromosomes are fully synapsed, and Holliday junctions are formed and then resolved into recombinants. ...
A study of human chromosome 22 showed a correlation between Z-DNA forming regions and promoter regions for nuclear factor I. ... since breakage regions in tumor cells have been plotted around Z-DNA-forming sequences. However, the smaller deletions in ... "Distributions of Z-DNA and nuclear factor I in human chromosome 22: a model for coupled transcriptional regulation". Nucleic ...
At this point the chromosomes are composed of nascent strands with BrdU in place of thymidine and the original template strands ... breakage-fusion-bridge cycle mediated complex DNA rearrangements, and chromothripsis events are sensitively detected in single ... In experiments used to study non-random chromosome assortment, stem cells are labeled or "pulsed" with a nucleotide analog that ... Contigs present in the same chromosome will exhibit the same directionality, provided SCE events have not occurred. Conversely ...
v t e (Articles with short description, Short description matches Wikidata, Genes on human chromosome X, All stub articles, ... increased chromosomal breakage, and defective DNA repair. The members of the Fanconi anemia complementation group do not share ... "FANCB is essential in the male germline and regulates H3K9 methylation on the sex chromosomes during meiosis". Hum. Mol. Genet ...
A high recombination rate could cause a chromosome to contain a large number of small segments with less correlated genealogies ... per unit genomic length was determined by the sum of a random number of smaller genomic segments derived by random breakage and ... Kendal, WS (2004). "A scale invariant clustering of genes on human chromosome 7". BMC Evol Biol. 4: 3. doi:10.1186/1471-2148-4- ... Kendal, WS (2007). "Scale invariant correlations between genes and SNPs on Human chromosome 1 reveal potential evolutionary ...
... asplenia miosis Thrombocytopathy Thrombocytopenia cerebellar hypoplasia short stature Thrombocytopenia chromosome breakage ...
In part because chromosomes may be very large, segments in the middle may act as if their ends are anchored. As a result, they ... and cannot be altered without strand breakage. The topology of the DNA is described by the equation below in which the linking ... Such a chromosome will be strained, just as a macroscopic metal spring is strained when it is either overwound or unwound. In ... The "relaxed" structure on the left is not found unless the chromosome is nicked; the superhelix is the form usually found in ...
Compared with modern wolves, some Pleistocene wolves showed an increase in tooth breakage similar to that seen in the extinct ... "Y-chromosome microsatellite variation in Italian wolves: A contribution to the study of wolf-dog hybridization patterns". ...
Unique banding patterns are used to identify chromosomes and to diagnose chromosomal aberrations, including chromosome breakage ... This would give rise to a chromosome abnormality such as an extra chromosome or one or more chromosomes lost. Abnormalities in ... The karyotype of humans includes only 46 chromosomes. The other great apes have 48 chromosomes. Human chromosome 2 is now known ... Human chromosome 2 appears to have resulted from the fusion of two ancestral chromosomes, and many of the genes of those two ...
... transferred but that breakage of the donor chromosome occurred at specific locations so that segments of the donor chromosome ... Zygotic induction occurs when a bacterial cell carrying the silenced DNA of a bacterial virus in its chromosome transfers the ... They did not believe that the entire donor chromosome was typically transferred to the recipient. On the other hand, Lederberg ... had an alternative explanation for the apparent ordered transfer of part of the chromosome. In analogy with fertilization and ...
... a circular structure called ring chromosome 22 that is caused by the breakage and reattachment of both ends of the chromosome. ... Chromosome 22 is one of the 23 pairs of chromosomes in human cells. Humans normally have two copies of chromosome 22 in each ... Chromosome 22 was the first human chromosome to be fully sequenced. Human chromosomes are numbered by their apparent size in ... "Chromosome 22: Chromosome summary - Homo sapiens". Ensembl Release 88. 29 March 2017. Retrieved 19 May 2017. "Human chromosome ...
Chromosome Breakage. A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL ... Thrombocytopenia chromosome breakage [Supplementary Concept]. Familial thrombocytopenia associated with platelet autoantibodies ... "chromosome breakage"[MeSH Terms] OR Chromosome Breakage[Text Word]. Search. See more... ...
Geisler A Chromosome Breakage in Children Treated with LSD-25 and UML-491 Comprehens. Psychiat. 1969 10:406-410 ... "Chromosome Breakage in Children Treated with LSD-25 and UML-491" Comprehens. Psychiat.. 1969;10:406-410. ... These workers could not correlate effects of LSD-25 with human chromosomal breakage. The question of the effect of LSD-25 is an ... have studied human leucocyte mitotic chromosomes both before and after administration of LSD-25 to the same group of subjects. ...
Start Over You searched for: Subjects Chromosome Breakage ✖Remove constraint Subjects: Chromosome Breakage ... Chromosome Breakage. Cytogenetics. Zea mays Archival Collection: The Barbara McClintock Papers (Profiles in Science) 4. The ... Chromosome Breakage Archival Collection: The Barbara McClintock Papers (Profiles in Science) 5. Changes in State of Ac -- the ... Chromosome Breakage. Gene Expression. Zea mays Archival Collection: The Barbara McClintock Papers (Profiles in Science) 10. ...
Dicentric chromosome breakage in Drosophila melanogaster is influenced by pericentric hete Dicentric chromosome breakage in ... We analyzed the breakage patterns of 3 different ring-X chromosomes. These chromosomes differ by the amount and quality of ... Chromosome breakage plays an important role in the evolution of karyotypes and can produce deleterious effects within a single ... Forces that influence how and where chromosomes break are not fully understood. In humans, breakage tends to occur in conserved ...
Replication Stress Induces Global Chromosome Breakage in the Fragile X Genome. Arijita Chakraborty, Piroon Jenjaroenpun, Jing ... Dive into the research topics of Replication Stress Induces Global Chromosome Breakage in the Fragile X Genome. Together they ...
... breaks and rearrangements in metaphase chromosomes when cells are cultured under conditions that inhibit DNA replication. ... as a constant feature in all individuals and their clinical significance is that they might predispose chromosomes to breakage ... breaks and rearrangements in metaphase chromosomes when cells are cultured under conditions that inhibit DNA replication. ...
Chromosome Breakage. Translocation, Genetic--physiology. Publication Types: Lecture. Webcast Download. NLM Classification: QS ...
Fanconis anemia: birth defects, marrow failure, early onset malignancy; positive chromosome breakage result. ...
Chromosome breakage studies (17). *. FISH-interphase (249). *. FISH-metaphase (222). *. Fluorescence in situ hybridization ( ...
MeSH Terms: Calibration; Camptothecin/pharmacology; Cells, Cultured; Chromatography/methods; Chromosome Breakage; DNA Damage/ ...
Chromosomal breakage study and positive family history should be included as major criteri … ... Chromosome Breakage* Actions. * Search in PubMed * Search in MeSH * Add to Search ... Metaphase spread showing increase in frequency of chromatid and chromosome gaps and breaks in our patients with CS. ... Metaphase spread showing increase in frequency of chromatid and chromosome gaps and breaks… ...
Categories: Chromosome Breakage Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, CopyrightRestricted ...
Chromosome breakage and cell cycle studies.. Berger R; Le Coniat M; Gendron MC. Cancer Genet Cytogenet; 1993 Aug; 69(1):13-6. ... 2. Sensitivity to chromosomal breakage as risk factor in young adults with oral squamous cell carcinoma.. Braakhuis BJ; ...
Diagnosis of Fanconi anemia (by chromosome breakage study). -Diffusion capacity of carbon monoxide (DLCO) less than 40 percent ...
This agent also participates in the breakage of chromosomes and modulation of immune response. ...
DMA did not produce cytologically detectable chromosome breakages.. Executive summary:. Male Wistar rats were exposed to 0.5 ... The incidence of cells with structural chromosome breakages was similar to that in the control preparations (0-2%), and was ... The incidence of cells with structural chromosome breakages was similar to that in the control preparations (0 - 2 %), and was ... The incidence of structural chromosome breakages and aneuploidy, recorded in metaphases of marrow cells, was used as the ...
In addition, chromosome breakage occurs more frequently in affected individuals. All of these changes are associated with gaps ... the DNA that makes up the chromosomes is copied so that each new cell will have two copies of each chromosome, one from each ... Exchange of DNA between chromosomes derived from the individuals mother and father are also increased in people with BLM gene ... The copied DNA from each chromosome is arranged into two identical structures, called sister chromatids. , which are attached ...
Ketorolac tromethamine did not cause chromosome breakage in the in vivo mouse micronucleus assay. At 1,590 mcg/mL and at higher ...
Ketorolac tromethamine did not cause chromosome breakage in the in vivo mouse micronucleus assay. At 1590 mcg/mL and at higher ...
This is consistent with an interaction between MDA and DNA resulting in chromosome breakage. However, BisGS-MDI and BisCYS-MDI ... The conventional MN assay does not discriminate between MN produced by acentric chromosome fragments from those arising due to ... This assay discerns the presence of centromere within the MN to distinguish the MN containing centric chromosomes from those ... whole lagging chromosomes that were not incorporated into daughter nuclei at the time of cell division. The mechanism of MN ...
This connection illustrates how an indispensable chromosome-disentangling machine auto-regulates DNA breakage to prevent the ...
It is known that during RNA synthesis R-loops can form and that aberrant R-loop formation can result in chromosome breakage. ...
Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.. Terms. Chromosome ... Chromosomal Breakage Chromosomal Breaks Chromosome Breaks Previous Indexing. Chromosome Aberrations (1967-1996). Chromosome ... Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.. Entry Term(s). ... Chromosome Breaks Narrower Concept UI. M0464742. Terms. Chromosome Breaks Preferred Term Term UI T583989. Date04/19/2004. ...
In cases of Downs Syndrome where there is a breakage andrealignment of human chromosome 21, the radiation doses resulting in ... chromosomebreakage are orders of magnitude higher that those found at this site.*The majority of the radioactive materials ...
  • These workers could not correlate effects of LSD-25 with human chromosomal breakage. (erowid.org)
  • The present paper summarizes our findings of chromosomal breakage in psychiatric patients of the Children's Unit. (erowid.org)
  • Chromosomal fragile sites are specific loci which are especially susceptible to forming gaps, breaks and rearrangements in metaphase chromosomes when cells are cultured under conditions that inhibit DNA replication. (nih.gov)
  • In all patients chromosomal breakage studies revealed mild (45%) to moderate (60%) increase in frequency of chromatid and chromosome gaps and breaks versus 25% in normal controls. (nih.gov)
  • 2. Sensitivity to chromosomal breakage as risk factor in young adults with oral squamous cell carcinoma. (nih.gov)
  • Results obtained in this study were inconsistent and characterised by small increases in chromosomal aberrations (simple chromatid breakage) with and without activation by liver S9 mix (Union Carbide Corp. Bushy Run Research Center 1986). (europa.eu)
  • While unequal crossing over could explain the generation of tandem duplications in proximity on the same chromosome, the generation of interspersed intra-chromosomal and inter-chromosomal duplications is difficult to explain by this mechanism [ 12 ]. (biomedcentral.com)
  • Our experimental approach was to induce sister chromatid exchange in a ring chromosome to generate a dicentric chromosome with a double chromatid bridge . (bvsalud.org)
  • Chromosome structure consist of two sister chromatid is held together by Centromere. (myhealth.gov.my)
  • Structural Maintenance of Chromosome (SMC) proteins are required for nuclear processes, including chromosome condensation, chromatid cohesion, and DNA repair. (novusbio.com)
  • This is a Claymation that shows how Barbara McClintock's classic breakage-fusion-bridge cycle causes chromosome abnormalities. (chromosomesandcancer.com)
  • The lack of hotspot conservation, along with a lack of response to aphidicolin , suggests that these breakage sites are not entirely analogous to CFS and may reveal new mechanisms of chromosome fragility . (bvsalud.org)
  • In humans , breakage tends to occur in conserved hotspots called common fragile sites (CFS), especially during replication stress. (bvsalud.org)
  • The common fragile sites are apparently present as a constant feature in all individuals and their clinical significance is that they might predispose chromosomes to breakage and rearrangement during cancer development. (nih.gov)
  • 1882: Wather Flemming was the first to illustrate the human chromosome, referred to as chromatin and for the first time the word "Mitosis" is used. (myhealth.gov.my)
  • Dicentric chromosome breakage in Drosophila melanogaster is influenced by pericentric heterochromatin and occurs in nonconserved hotspots. (bvsalud.org)
  • By following the fate of dicentric chromosomes in Drosophila melanogaster , we find that breakage under tension also tends to occur in specific hotspots. (bvsalud.org)
  • Additionally, the frequency of dicentric breakage and the durability of each chromosome 's spindle attachment vary significantly between the 3 chromosomes and are correlated with the origin of the centromere and the amount of pericentric heterochromatin . (bvsalud.org)
  • The dicentric chromosome dic(20;22) is a recurrent abnormality in myelodysplastic syndromes and is a product of telomere fusion. (chromosomesandcancer.com)
  • Spread of Mutation Change Along Chromosome. (nih.gov)
  • For all 3 chromosomes , breakage occurs preferentially in several hotspots. (bvsalud.org)
  • In addition, chromosome breakage occurs more frequently in affected individuals. (medlineplus.gov)
  • have studied human leucocyte mitotic chromosomes both before and after administration of LSD-25 to the same group of subjects. (erowid.org)
  • At the end of chromosome, a protective cap known as Telomere that protect from DNA degradation during chromosome breakage and prevent end to end fusion of chromosome. (myhealth.gov.my)
  • Sometimes only part of the telomere erodes away - enough is lost that it no longer protects the chromosomes from sticking together. (chromosomesandcancer.com)
  • This is the left-over telomere signature that tells us that this abnormal chromosome was made by the joining together of sticky chromosome ends that had their telomeres eroded away. (chromosomesandcancer.com)
  • In our four cases we found that there was a small but non-functional piece of telomere DNA left behind where the two chromosomes joined. (chromosomesandcancer.com)
  • For simplicity the Claymation shows telomere fusion in chromosomes that are dividing . (chromosomesandcancer.com)
  • The question of the effect of LSD-25 is an extremely important one, not only because of the psychopharmacological effects of LSD-25, but also because of the possibilty that many drugs may act on chromosomes, with resultant effects on the genetic information, both in humans and animals, during extended periods of drug administration, as is the case in psychiatric patients. (erowid.org)
  • This connection illustrates how an indispensable chromosome-disentangling machine auto-regulates DNA breakage to prevent the aberrant formation of mutagenic and cytotoxic genomic lesions. (rcsb.org)
  • It is known that during RNA synthesis R-loops can form and that aberrant R-loop formation can result in chromosome breakage. (nih.gov)
  • This assay discerns the presence of centromere within the MN to distinguish the MN containing centric chromosomes from those containing acentric fragments. (cdc.gov)
  • The conventional MN assay does not discriminate between MN produced by acentric chromosome fragments from those arising due to whole lagging chromosomes that were not incorporated into daughter nuclei at the time of cell division. (cdc.gov)
  • In cell's nucleus, DNA is tightly coiled with histone protein and is packaged into thread-like macromolecule called Chromosome. (myhealth.gov.my)
  • These caused breakage-fusion-bridge events that caused a protective tumour suppressor gene to be lost, and may have also caused cancer-causing genes to multiply. (chromosomesandcancer.com)
  • The 46 long strings of genes in each human cell are folded up to form chromosomes, which we can see down the microscope. (chromosomesandcancer.com)
  • 1921: Theophilus Painter was the first to concluded that number of human chromosome is 24 with his observation under microscope. (myhealth.gov.my)
  • Until 1956, scientist realized the real number of human chromosome is 23. (myhealth.gov.my)
  • Chromosome breakage and cell cycle studies. (nih.gov)
  • positive chromosome breakage result. (nih.gov)
  • Chromosome breakage plays an important role in the evolution of karyotypes and can produce deleterious effects within a single individual, such as aneuploidy or cancer . (bvsalud.org)
  • This complicated structure could not have been predicted by the standard methods of analysing cancer DNA or chromosomes . (chromosomesandcancer.com)
  • When a cell prepares to divide to form two cells, the DNA that makes up the chromosomes is copied so that each new cell will have two copies of each chromosome, one from each parent. (medlineplus.gov)
  • 1888: Waldeyer introduced the word "Chromosome" that is derived from Greek word. (myhealth.gov.my)
  • Surprisingly, we found that the hotspot locations are not conserved between the 3 chromosomes each displays a unique array of breakage hotspots. (bvsalud.org)