Aneuploidy: 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).Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.Chromosomes: 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)Chromosomes, Human: 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.Chromosomes, Human, Pair 21: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Hybrid 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.Chromosome Banding: 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.Chromosomes, Human, 6-12 and X: 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.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.Chromosomes, Human, Pair 1: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.X Chromosome: 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.Chromosomes, Human, Pair 7: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.In Situ Hybridization, Fluorescence: 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.Karyotyping: Mapping of the KARYOTYPE of a cell.Sex Chromosomes: 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)Chromosomes, Human, 1-3: The large, metacentric human chromosomes, called group A in the human chromosome classification. This group consists of chromosome pairs 1, 2, and 3.Chromosomes, Human, Pair 11: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Chromosome Segregation: The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.Chromosomes, Human, 16-18: The short, submetacentric human chromosomes, called group E in the human chromosome classification. This group consists of chromosome pairs 16, 17, and 18.Chromosomes, Human, Pair 17: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 6: A specific pair GROUP C CHROMSOMES of the human chromosome classification.Chromosomes, Human, Pair 19: A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 22: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 16: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 12: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 13: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 8: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 9: A specific pair of GROUP C CHROMSOMES of the human chromosome classification.Chromosome Disorders: 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)Chromosomes, Human, Pair 2: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.Chromosome Painting: 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.Chromosome Deletion: Actual loss of portion of a chromosome.Molecular Sequence Data: 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.Chromosomes, Human, Pair 10: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 18: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.Chromosomes, Artificial, Yeast: 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.Chromosomes, Human, Pair 4: A specific pair of GROUP B CHROMOSOMES of the human chromosome classification.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Genetic Linkage: The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.Chromosomes, Human, 21-22 and Y: 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.Chromosomes, Mammalian: Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of MAMMALS.Chromosomes, Human, 13-15: The medium-sized, acrocentric human chromosomes, called group D in the human chromosome classification. This group consists of chromosome pairs 13, 14, and 15.Chromosomes, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.Genetic Markers: A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.Chromosomes, Human, X: The human female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in humans.Chromosomes, Human, Pair 15: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 20: A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.Chromosomes, Human, 4-5: The large, submetacentric human chromosomes, called group B in the human chromosome classification. This group consists of chromosome pairs 4 and 5.Chromosomes, Fungal: Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.Chromosomes, Human, Pair 5: One of the two pairs of human chromosomes in the group B class (CHROMOSOMES, HUMAN, 4-5).Chromosomes, Human, Y: The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.Chromosomes, Plant: Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.Chromosomes, Human, Pair 14: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Chromosomal Instability: An increased tendency to acquire CHROMOSOME ABERRATIONS when various processes involved in chromosome replication, repair, or segregation are dysfunctional.Trisomy: The possession of a third chromosome of any one type in an otherwise diploid cell.Centromere: 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.Chromosomes, Artificial, Bacterial: 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.Chromosome Pairing: The alignment of CHROMOSOMES at homologous sequences.Chromosome Breakage: A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.Metaphase: 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.DNA: 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).Cloning, Molecular: 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.Chromosomes, Human, 19-20: The short, metacentric human chromosomes, called group F in the human chromosome classification. This group consists of chromosome pairs 19 and 20.Meiosis: 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.Translocation, Genetic: A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.Down Syndrome: A chromosome disorder associated either with an extra chromosome 21 or an effective trisomy for chromosome 21. Clinical manifestations include hypotonia, short stature, brachycephaly, upslanting palpebral fissures, epicanthus, Brushfield spots on the iris, protruding tongue, small ears, short, broad hands, fifth finger clinodactyly, Simian crease, and moderate to severe INTELLECTUAL DISABILITY. Cardiac and gastrointestinal malformations, a marked increase in the incidence of LEUKEMIA, and the early onset of ALZHEIMER DISEASE are also associated with this condition. Pathologic features include the development of NEUROFIBRILLARY TANGLES in neurons and the deposition of AMYLOID BETA-PROTEIN, similar to the pathology of ALZHEIMER DISEASE. (Menkes, Textbook of Child Neurology, 5th ed, p213)Nucleic Acid Hybridization: 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)Mitosis: 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.Chromosome Inversion: 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.Amino Acid Sequence: 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.DNA, Satellite: 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.Genes: 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.Sequence Tagged Sites: 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.Nondisjunction, Genetic: 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.Mosaicism: 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.Cosmids: Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.Ploidies: The degree of replication of the chromosome set in the karyotype.Recombination, Genetic: 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.Preimplantation Diagnosis: Determination of the nature of a pathological condition or disease in the OVUM; ZYGOTE; or BLASTOCYST prior to implantation. CYTOGENETIC ANALYSIS is performed to determine the presence or absence of genetic disease.Chromosome Positioning: The mechanisms of eukaryotic CELLS that place or keep the CHROMOSOMES in a particular SUBNUCLEAR SPACE.DNA Probes: 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.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Diploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.Pedigree: 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.Mutation: 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.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Chromosomes, Artificial, Human: 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.Blotting, Southern: 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.Polyploidy: The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.Polymerase Chain Reaction: 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.Ring Chromosomes: Aberrant chromosomes with no ends, i.e., circular.Microsatellite Repeats: 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).Repetitive Sequences, Nucleic Acid: 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).Cell Line: Established cell cultures that have the potential to propagate indefinitely.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Genome, Human: 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.Multigene Family: 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)Physical Chromosome Mapping: Mapping of the linear order of genes on a chromosome with units indicating their distances by using methods other than genetic recombination. These methods include nucleotide sequencing, overlapping deletions in polytene chromosomes, and electron micrography of heteroduplex DNA. (From King & Stansfield, A Dictionary of Genetics, 5th ed)Telomere: 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.Spindle Apparatus: 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.Lod Score: The total relative probability, expressed on a logarithmic scale, that a linkage relationship exists among selected loci. Lod is an acronym for "logarithmic odds."Crosses, Genetic: 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.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Sequence Homology, Nucleic Acid: 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.Chromosomes, Human, Pair 3: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.Contig Mapping: Overlapping of cloned or sequenced DNA to construct a continuous region of a gene, chromosome or genome.Models, Genetic: 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.Chromosome Fragility: Susceptibility of chromosomes to breakage leading to translocation; CHROMOSOME INVERSION; SEQUENCE DELETION; or other CHROMOSOME BREAKAGE related aberrations.Karyotype: 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)Cytogenetics: 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.X Chromosome Inactivation: 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.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Cytogenetic Analysis: 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.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Gene Dosage: 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.Abnormal Karyotype: A variation from the normal set of chromosomes characteristic of a species.Exons: The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.DNA, Neoplasm: DNA present in neoplastic tissue.Kinetochores: Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.Sequence Alignment: 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.Chromosomes, Insect: Structures within the CELL NUCLEUS of insect cells containing DNA.Polymorphism, Restriction Fragment Length: 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.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Genes, Tumor Suppressor: Genes that inhibit expression of the tumorigenic phenotype. They are normally involved in holding cellular growth in check. When tumor suppressor genes are inactivated or lost, a barrier to normal proliferation is removed and unregulated growth is possible.Chromosome Fragile Sites: 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.)Polymorphism, Genetic: 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.Radiation Hybrid Mapping: A method for ordering genetic loci along CHROMOSOMES. The method involves fusing irradiated donor cells with host cells from another species. Following cell fusion, fragments of DNA from the irradiated cells become integrated into the chromosomes of the host cells. Molecular probing of DNA obtained from the fused cells is used to determine if two or more genetic loci are located within the same fragment of donor cell DNA.Chromosome Structures: Structures which are contained in or part of CHROMOSOMES.Chromosome Duplication: An aberration in which an extra chromosome or a chromosomal segment is made.Haplotypes: 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.Chromosomal Proteins, Non-Histone: 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.Genomic Imprinting: The variable phenotypic expression of a GENE depending on whether it is of paternal or maternal origin, which is a function of the DNA METHYLATION pattern. Imprinted regions are observed to be more methylated and less transcriptionally active. (Segen, Dictionary of Modern Medicine, 1992)DNA-Binding Proteins: 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.Monosomy: The condition in which one chromosome of a pair is missing. In a normally diploid cell it is represented symbolically as 2N-1.Cell Cycle Proteins: 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.Chromatids: 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)Interphase: 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).Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Pseudogenes: Genes bearing close resemblance to known genes at different loci, but rendered non-functional by additions or deletions in structure that prevent normal transcription or translation. When lacking introns and containing a poly-A segment near the downstream end (as a result of reverse copying from processed nuclear RNA into double-stranded DNA), they are called processed genes.Loss of Heterozygosity: 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.Abnormalities, MultiplePregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Species Specificity: 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.Gene Duplication: Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.Chromosome Walking: 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.Heterozygote: An individual having different alleles at one or more loci regarding a specific character.Mad2 Proteins: Mad2 is a component of the spindle-assembly checkpoint apparatus. It binds to and inhibits the Cdc20 activator subunit of the anaphase-promoting complex, preventing the onset of anaphase until all chromosomes are properly aligned at the metaphase plate. Mad2 is required for proper microtubule capture at KINETOCHORES.Genomic Library: A form of GENE LIBRARY containing the complete DNA sequences present in the genome of a given organism. It contrasts with a cDNA library which contains only sequences utilized in protein coding (lacking introns).Centrosome: The cell center, consisting of a pair of CENTRIOLES surrounded by a cloud of amorphous material called the pericentriolar region. During interphase, the centrosome nucleates microtubule outgrowth. The centrosome duplicates and, during mitosis, separates to form the two poles of the mitotic spindle (MITOTIC SPINDLE APPARATUS).Nuclear Proteins: 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.Gene Library: A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.Azure Stains: PHENOTHIAZINES with an amino group at the 3-position that are green crystals or powder. They are used as biological stains.Polar Bodies: Minute cells produced during development of an OOCYTE as it undergoes MEIOSIS. A polar body contains one of the nuclei derived from the first or second meiotic CELL DIVISION. Polar bodies have practically no CYTOPLASM. They are eventually discarded by the oocyte. (from King & Stansfield, A Dictionary of Genetics, 4th ed)DNA Primers: 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.Genetic Variation: Genotypic differences observed among individuals in a population.Infertility, Male: The inability of the male to effect FERTILIZATION of an OVUM after a specified period of unprotected intercourse. Male sterility is permanent infertility.Aneugens: Agents which affect CELL DIVISION and the MITOTIC SPINDLE APPARATUS resulting in the loss or gain of whole CHROMOSOMES, thereby inducing an ANEUPLOIDY.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Genomic Instability: An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.Gene Deletion: 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.DNA Restriction Enzymes: Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.Klinefelter Syndrome: A form of male HYPOGONADISM, characterized by the presence of an extra X CHROMOSOME, small TESTES, seminiferous tubule dysgenesis, elevated levels of GONADOTROPINS, low serum TESTOSTERONE, underdeveloped secondary sex characteristics, and male infertility (INFERTILITY, MALE). Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several karyotype variants include 48,XXYY; 48,XXXY; 49,XXXXY, and mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).Quantitative Trait Loci: Genetic loci associated with a QUANTITATIVE TRAIT.Aurora Kinases: A family of highly conserved serine-threonine kinases that are involved in the regulation of MITOSIS. They are involved in many aspects of cell division, including centrosome duplication, SPINDLE APPARATUS formation, chromosome alignment, attachment to the spindle, checkpoint activation, and CYTOKINESIS.Y Chromosome: The male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans and in some other male-heterogametic species in which the homologue of the X chromosome has been retained.Introns: Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.Sex Chromosome Disorders: 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).Cell Nucleus: 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)Oocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).Genome: The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.Comparative Genomic Hybridization: A method for comparing two sets of chromosomal DNA by analyzing differences in the copy number and location of specific sequences. It is used to look for large sequence changes such as deletions, duplications, amplifications, or translocations.Prenatal Diagnosis: Determination of the nature of a pathological condition or disease in the postimplantation EMBRYO; FETUS; or pregnant female before birth.Haploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented once. Symbol: N.DNA Replication: The process by which a DNA molecule is duplicated.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.XYY Karyotype: Abnormal genetic constitution in males characterized by an extra Y chromosome.Euchromatin: Chromosome regions that are loosely packaged and more accessible to RNA polymerases than HETEROCHROMATIN. These regions also stain differentially in CHROMOSOME BANDING preparations.Maternal Age: The age of the mother in PREGNANCY.Genetic Testing: Detection of a MUTATION; GENOTYPE; KARYOTYPE; or specific ALLELES associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing.Plasmids: 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.Cell Transformation, Neoplastic: Cell changes manifested by escape from control mechanisms, increased growth potential, alterations in the cell surface, karyotypic abnormalities, morphological and biochemical deviations from the norm, and other attributes conferring the ability to invade, metastasize, and kill.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Lymphocytes: 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.Oligospermia: A condition of suboptimal concentration of SPERMATOZOA in the ejaculated SEMEN to ensure successful FERTILIZATION of an OVUM. In humans, oligospermia is defined as a sperm count below 20 million per milliliter semen.Gorilla gorilla: This single species of Gorilla, which is a member of the HOMINIDAE family, is the largest and most powerful of the PRIMATES. It is distributed in isolated scattered populations throughout forests of equatorial Africa.Cricetulus: A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.Chromatin: 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.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Gene Amplification: 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.Sister Chromatid Exchange: 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.Prader-Willi Syndrome: An autosomal dominant disorder caused by deletion of the proximal long arm of the paternal chromosome 15 (15q11-q13) or by inheritance of both of the pair of chromosomes 15 from the mother (UNIPARENTAL DISOMY) which are imprinted (GENETIC IMPRINTING) and hence silenced. Clinical manifestations include MENTAL RETARDATION; MUSCULAR HYPOTONIA; HYPERPHAGIA; OBESITY; short stature; HYPOGONADISM; STRABISMUS; and HYPERSOMNOLENCE. (Menkes, Textbook of Child Neurology, 5th ed, p229)Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.Cell Cycle: 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.Chromosomes, Artificial, P1 Bacteriophage: DNA constructs that are derived from the DNA of BACTERIOPHAGE P1. They can carry large amounts (about 100-300 kilobases) of other sequence for a variety of bioengineering purposes.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.Spectral Karyotyping: The simultaneous identification of all chromosomes from a cell by fluorescence in situ hybridization (IN SITU HYBRIDIZATION, FLUORESCENCE) with chromosome-specific florescent probes that are discerned by their different emission spectra.
Apart from sex chromosome disorders, most cases of aneuploidy result in death of the developing fetus (miscarriage); the most ... The human nucleotide diversity is estimated to be 0.1% to 0.4% of base pairs. A difference of 1 in 1,000 amounts to ... According to a 2000 study of Y-chromosome sequence variation, human Y-chromosomes trace ancestry to Africa, and the descendants ... No two humans are genetically identical. On average, in DNA sequence, each human is 99.5% similar to any other human. Even ...
... marker chromosome, gross rearrangements and variation in chromosome size. The frequency in human population is thought to be ... Qi, Ji; Fangqing Zhao (June 2011). "inGAP-sv: a novel scheme to identify and visualize structural variation from paired end ... Microscopic means that it can be detected with optical microscopes, such as aneuploidies, ... Wyandt, H. E.; Tonk, V. S. (2004). Atlas of Human Chromosome Heteromorphisms. Netherlands: Kluwer Academic. ISBN 978-90-481- ...
... the sex chromosomes (in humans, the X chromosome and Y chromosome), which are responsible for determining the sex of an ... bacterial artificial chromosome (BAC) base pair A pair of nucleotide bases on complementary DNA or RNA strands organized in a ... anaphase aneuploidy anticodon autosome Contents: Top 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ... X chromosome X-linked trait Y chromosome yeast artificial chromosome (YAC) Contents: Top 0-9 A B C D E F G H I J K L M N O P Q ...
As this karyotype displays, a diploid human cell contains 22 pairs of homologous chromosomes and 2 sex chromosomes.. Section ... It follows from the definition that male humans have a monoploid number of 22, while females have 23 (including one X-X pair). ... The term "aneuploidy" refers to an abnormal numbers of nuclear chromosomes; extra-nuclear genomes are not counted. It's ... chromosomes." For example, the number of homologous sets of chromosomes in humans is 23 if one considers a "set" to be one pair ...
Human females are typically XX; males are typically XY. The remaining pairs of chromosome are found in both sexes and are ... except in the case of certain types of Y chromosome aneuploidy), that allele is always expressed regardless of whether it is ... In humans and other mammal species, sex is determined by two sex chromosomes called the X chromosome and the Y chromosome. ... Most animals and some plants have paired chromosomes, and are described as diploid. They have two versions of each chromosome, ...
The term sex chromosome aneuploidy summarizes conditions with an abnormal number of sex chromosomes, i.e. other than XX (female ... almost all chromosome pairs are joined by at least one crossover, while more than 10% of human oocytes contain at least one ... Gaining a single chromosome, in which the daughter cell(s) with the defect will have one chromosome in addition to its pairs is ... Klinefelter syndrome is the most common sex chromosome aneuploidy in humans. It represents the most frequent cause of ...
On a normal karyotype, aneuploidy can be detected by clearly being able to observe any missing or extra chromosomes. Giemsa ... XX), and are called the homogametic sex. Males have two distinct sex chromosomes (XY), and are called the heterogametic sex. ... the sex of an individual is determined by a pair of sex chromosomes (gonosomes). Females have two of the same kind of sex ... The human genome is the total collection of genes in a human being contained in the human chromosome, composed of over three ...
The DNA in the human Y chromosome is composed of about 59 million base pairs. The Y chromosome is passed only from father to ... Klinefelter syndrome (47, XXY) is not an aneuploidy of the Y chromosome, but a condition of having an extra X chromosome, which ... in addition to the ancestral XX female, through a variety of modifications to the X and Y chromosomes. In the creeping vole, ... Stevens proposed that chromosomes always existed in pairs and that the Y chromosome was the pair of the X chromosome discovered ...
They are found to be missing the same portion of the Y chromosome it was inserted into the chromosome of XX males. The gene for ... The genotype of the male consists of a Y chromosome paired with an X chromosome. Female gender is determined by the absence of ... An abnormal number of sex chromosomes (aneuploidy) may can occur. This includes Turner's syndrome - a single X chromosome is ... Redirected from Human male reproductive system). This article is about the reproductive system in human males. For the male ...
XX males or XY females (see androgen insensitivity syndrome). Additionally, an abnormal number of sex chromosomes (aneuploidy) ... In humans, most mammals, and some other species, two of the chromosomes, called the X chromosome and Y chromosome, code for sex ... where just one chromosome type appears in pairs for the female but alone in the males, while all other chromosomes appear in ... In humans, half of spermatozoons carry X chromosome and the other half Y chromosome. A single gene (SRY) present on the Y ...
... blood cells of 66 pairs of monozygotic twins was analyzed for 506,786 single nucleotide polymorphisms known to occur in human ... Even if they happen to have the same chromosome profile, they will always have different genetic material on each chromosome, ... Twenty-six percent of twins were monozygotic. The incidence of multiple births, which was about five times higher than that ... due to aneuploidy, twins may express different sexual phenotypes, normally from an XXY Klinefelter syndrome zygote splitting ...
Sauter, G; Moch, H; Gasser, T. C.; Mihatsch, M. J.; Waldman, F. M. (1995). "Heterogeneity of chromosome 17 and erbB-2 gene copy ... Horvai, A. E.; Devries, S; Roy, R; O'Donnell, R. J.; Waldman, F (2009). "Similarity in genetic alterations between paired well- ... Current model systems typically lack the heterogeneity seen in human cancers. In order to accurately study tumour heterogeneity ... Association with degree of DNA aneuploidy". The American Journal of Pathology. 149 (1): 237-245. PMC 1865212 . PMID 8686748. ...
Harper, Peter S. (2006). "The sex chromosomes". First years of human chromosomes : the beginnings of human cytogenetics. ... "Usually girls have XX chromosomes and boys have XY, but this killer is XYY, which means too much testosterone." Among other ... In contrast to the other common sex chromosome aneuploidies-47,XXX and 47,XXY (Klinefelter syndrome)-the average IQ scores of ... it appears that XY pairing and recombination occur normally in 47,XYY, the extra Y chromosome being lost during spermatogenesis ...
The great apes have 48 chromosomes. Human chromosome 2 was formed by a merger of ancestral chromosomes, reducing the number. ... which revealed unique banding patterns for each chromosome pair. This allowed chromosome pairs of otherwise equal size to be ... The ability for mammals to tolerate aneuploidies in the sex chromosomes arises from the ability to inactivate them, which is ... Hans von Winiwarter reported 47 chromosomes in spermatogonia and 48 in oogonia, concluding an XX/XO sex determination mechanism ...
Nowell PC, Hungerford DA (July 1960). "Chromosome studies on normal and leukemic human leukocytes". J. Natl. Cancer Inst. 25: ... and karyotypic variations including chromosome structural aberrations and aneuploidy. Studies of this issue have focused mainly ... while in most cases loss of expression is due to methylation of the promoter of its pairing partner MLH1 (PMS2 is unstable in ... February 1999). "Superimposed histologic and genetic mapping of chromosome 9 in progression of human urinary bladder neoplasia ...
"Chromosomes, Chromosome Anomalies". *Gilbert F (1999). "Disease genes and chromosomes: disease maps of the human genome. ... Aneuploidy). A telocentric chromosome's centromere is located at the terminal end of the chromosome. Telomeres may extend from ... The centromere is the part of a chromosome that links a pair of sister chromatids (a dyad). During mitosis, spindle fibers ... The human genome includes six acrocentric chromosomes: 13, 14, 15, 21, 22 and the Y chromosome. In an acrocentric chromosome ...
Humans have one pair fewer chromosomes than the great apes. Human chromosome 2 appears to have resulted from the fusion of two ... AneuploidyEdit. Aneuploidy is the condition in which the chromosome number in the cells is not the typical number for the ... Differences in absolute sizes of chromosomes. Chromosomes can vary in absolute size by as much as twenty-fold between genera of ... The normal human karyotypes contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes (allosomes). Normal ...
For example, in humans, females (XX) silence the transcription of one X chromosome of each pair, and transcribe all information ... dosage compensation can occur when aberrant meiotic events or mutations result in either aneuploidy or polyploidy. Genes on the ... of the Y chromosome during meiosis. Additionally, 10-25% of human X chromosome genes, and 3-7% of mouse X chromosome genes ... Specifically, platypus X1 shares homology with the chicken Z chromosome, and both share homology with the human chromosome 9. ...
The institute is also the first develop a test to detect chromosome translocations in human embryos to increase the success ... Another PDG work on aneuploidy also received the prize paper of the Society for Assisted Reproductive Technology in 1998 Other ... 2009 First Paired Kidney Exchange in New Jersey Performed, Family Health Magazine, Spring/Summer 2006 - accessed July 11, 2009 ... Human cloning is a long way off, but bioengineered kids are already here, Washington Monthly, March 2002 - accessed July 11, ...
Chromosome abnormalities are detected in 1 of 160 live human births. Most cells in the human body have 23 pairs of chromosomes ... Occupational exposure to benzene is associated with a 2.8-fold increase of XX disomy and a 2.6-fold increase of YY disomy in ... Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes ... The 23rd pair of chromosomes are the sex chromosomes. Normal females have two X chromosomes, while normal males have one X ...
The CDK6 gene is located on chromosome 7 in humans. The gene spans 231,706 base pairs and encodes a 326 amino acid protein with ... this could lead to division problems such as aneuploidy, which in turns leads to health issues like primary microcephaly. CDK6 ... Cyclin-Dependent Kinase 6 at the US National Library of Medicine Medical Subject Headings (MeSH) CDK6 human gene location in ... CDK6 human gene details in the UCSC Genome Browser. Molecular and Cellular Biology portal. ...
European Journal of Human Genetics. 21 (8): 887-90. doi:10.1038/ejhg.2012.267. PMID 23232695. Rare Chromosome Disorder Support ... The DNA samples (which are 25-80 base pairs in length) are then placed on slides to be observed under microscope. Lastly, EHMT1 ... It can be used for gene mapping, detecting aneuploidy, locating tumours etc. The multicolour probes attach to a certain DNA ... She later gained weight at eleven and developed epilepsy in her late twenty's. The fourth patient had problems associated with ...
Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving a total of 46 per cell ... Aneuploidy Chromosome segregation DNA Genetic deletion For information about chromosomes in genetic algorithms, see chromosome ... Like many sexually reproducing species, humans have special gonosomes (sex chromosomes, in contrast to autosomes). These are XX ... Chromosomes in humans can be divided into two types: autosomes (body chromosome(s)) and allosome (sex chromosome(s)). Certain ...
In humans, examples of aneuploidy include having a single extra chromosome (such as Down syndrome), or missing a chromosome ( ... The haploid gametes produced by most organisms combine to form a zygote with n pairs of chromosomes, i.e. 2n chromosomes in ... "46,XX/69,XXX diploid-triploid mixoploidy with hypothyroidism and precocious puberty". J Med Genet. 30: 966-7. doi:10.1136/jmg. ... For example, most human cells have 2 of each of the 23 homologous monoploid chromosomes, for a total of 46 chromosomes. A human ...
The X chromosome in humans spans more than 153 million base pairs (the building material of DNA). It represents about 800 ... where the SRY region of the Y chromosome has recombined to be located on one of the X chromosomes. As a result, the XX ... Visootsak J, Graham JM (2006). "Klinefelter syndrome and other sex chromosomal aneuploidies". Orphanet J Rare Dis. 1: 42. doi: ... Each person usually has one pair of sex chromosomes in each cell. Females have two X chromosomes, whereas males have one X and ...
Genetics (from Ancient Greek γενετικός genetikos, "genite" and that from γένεσις genesis, "origin"), a discipline of biology, is the science of heredity and variation in living organisms. Articles (arranged alphabetically) related to genetics include: Contents: Top 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 3' end 5' end Acentric chromosome Achondroplasia Active site Adam's Curse Adaptation Adenine Adenosine Adenovirus Adenosine diphosphate (ADP) Ala Alagille syndrome Albino Alcoholism Alkylating agent Allele Allele frequency Alleles Allopolyploid Allosteric protein Allozyme Alternative splicing Altruism Alu family Alzheimer's disease Amber codon Ames test Amino acid Amino acid sequence Amino acids Amniocentesis Amorph AMP Amphidiploid Amplification Anagenesis Anaphase Aneuploid Aneuploid cell Aneuploidy Angelman syndrome Angiosperm Animal model Annealing Annotation Antibody Anticipation Anticoding strand Anticodon Antigen Antimorph Antiparallel Antisense Antisense ...
Treatments exist for the various symptoms associated with XXXY syndrome. Testosterone therapy, which is giving affected individuals doses of testosterone on a regular basis, has been shown to reduce aggressive behavior in these patients.[3] But, this therapy has also been associated with negative side effects: worsening of behavior, and osteoporosis.[3] Not all individuals are applicable for testosterone therapy, as the best results are often achieved when dosage begins at the initiation of puberty, and these individuals are often diagnosed at a later age, or not at all.[3] Testosterone therapy has been shown to have no positive effect on fertility.[2] Consideration of the psychological phenotype of individuals with XXXY should be taken into account when treating these patients, because these traits affect compliance with treatments.[3] When caught early, Taurodontism can be treated with a root canal and is often successful.[2] Appropriate planning to avoid Taurodontism is possible, but this ...
During the process of cell division, the spindle checkpoint prevents separation of the duplicated chromosomes until each chromosome is properly attached to the spindle apparatus. In order to preserve the cell's identity and proper function, it is necessary to maintain the appropriate number of chromosomes after each cell division. An error in generating daughter cells with fewer or greater number of chromosomes than expected (a situation termed aneuploidy), may lead in best case to cell death, or alternatively it may generate catastrophic phenotypic results. Examples include: In cancer cells, aneuploidy is a frequent event, indicating that these cells present a defect in the machinery involved in chromosome segregation, as well as in the mechanism ensuring that segregation is correctly performed. In humans, Down syndrome appears in children carrying in their cells one extra copy of ...
From early meiotic studies, it was concluded that the extra Y was eliminated before the spermatocyte formed, with an X-Y bivalent usually seen at diakinesis, and more recent studies support this concept. However, FISH analyses of sperm, enabling hundreds of cells to be analyzed, have shown a very small increased faction of 24,YY spermatozoa in the ejaculate of XYY men (Table 12-1). Thus it appears the vast majority of spermatocytes lose the extra Y before entering meiosis, a very few XYY primary spermatocytes are able to slip through and produce YY (and XY) spermatozoa. These cytogenetic findings parallel the observation that XYY men have no discernible increase in risk to have children with a sex chromosome abnormality. A true increased risk of a fraction of a per cent could be distinguished only with the greatest of difficulty when the background population risk is of a similar order of magnitude. As for the autosomes, no convincing case exists for any increased risk for aneuploidy in the ...
Although men considering vasectomies should not think of them as reversible, and most men and their partners are satisfied with the operation,[47][48] life circumstances and outlooks can change, and there is a surgical procedure to reverse vasectomies using vasovasostomy (a form of microsurgery first performed by Earl Owen in 1971[49][50]). Vasovasostomy is effective at achieving pregnancy in a variable percentage of cases, and total out-of-pocket costs in the United States are often upwards of $10,000.[51] The typical success rate of pregnancy following a vasectomy reversal is around 55% if performed within 10 years, and drops to around 25% if performed after 10 years.[52] After reversal, sperm counts and motility are usually much lower than pre-vasectomy levels. There is evidence that men who have had a vasectomy may produce more abnormal sperm, which would explain why even a mechanically successful reversal does not always restore fertility.[53][54] The higher rates of aneuploidy and ...
Although men considering vasectomies should not think of them as reversible, and most men and their partners are satisfied with the operation,[45][46] life circumstances and outlooks can change, and there is a surgical procedure to reverse vasectomies using vasovasostomy (a form of microsurgery first performed by Earl Owen in 1971[47][48]). Vasovasostomy is effective at achieving pregnancy in a variable percentage of cases, and total out-of-pocket costs in the United States are often upwards of $10,000.[49] The typical success rate of pregnancy following a vasectomy reversal is around 55% if performed within 10 years, and drops to around 25% if performed after 10 years.[50] After reversal, sperm counts and motility are usually much lower than pre-vasectomy levels. There is evidence that men who have had a vasectomy may produce more abnormal sperm, which would explain why even a mechanically successful reversal does not always restore fertility.[51][52] The higher rates of aneuploidy and ...
In genetics, complete linkage is defined as the state in which two loci are so close together that alleles of these loci are virtually never separated by crossing over. The closer the physical location of two genes on the DNA, the less likely they are to be separated by a crossing-over event. In the case of male Drosophila there is complete absence of recombinant types due to absence of crossing over. This means that all of the genes that start out on a single chromosome, will end up on that same chromosome in their original configuration. In the absence of recombination, only parental phenotypes are expected. Genetic Linkage is the tendency of alleles, which are located closely together on a chromosome, to be inherited together during the process of meiosis in sexually reproducing organisms. During the process of meiosis, homologous chromosomes pair up, and can exchange corresponding sections of DNA. As a result, genes that were originally on the same chromosome can finish ...
... s help describe the spatial arrangement of genes on a chromosome. Genes are designated to a specific location on a chromosome known as the locus and can be used as molecular markers to find the distance between other genes on a chromosome. Maps provide researchers with the opportunity to predict the inheritance patterns of specific traits, which can eventually lead to a better understanding of disease-linked traits. The genetic basis to gene maps is to provide an outline that can potentially help researchers carry out DNA sequencing. A gene map helps point out the relative positions of genes and allows researchers to locate regions of interest in the genome. Genes can then be identified quickly and sequenced quickly. Two approaches to generating gene maps include physical mapping and genetic mapping. Physical mapping utilizes molecular biology techniques to inspect chromosomes. These techniques consequently allow researchers to observe chromosomes directly so that a map ...
The number of base-pairs to which it corresponds varies widely across the genome (different regions of a chromosome have different propensities towards crossover) and it also depends on if the meiosis where the crossing-over takes place is a part of oogenesis (formation of female gametes) or spermatogenesis (formation of male gametes). One centimorgan corresponds to about 1 million base pairs in humans on average.[1][2] The relationship is only rough as the physical chromosomal distance corresponding to one centimorgan varies from place to place in the genome, and also varies between men and women since recombination during gamete formation in females is significantly more frequent than in males. Morton et al. calculated that the female genome is 4782 centimorgans long, while the male genome is only 2809 centimorgans long.[3] Plasmodium falciparum has an average recombination distance of ~15 kb per centimorgan: markers separated by 15 kb of ...
Fossey SC، Mychaleckyj JC، Pendleton JK، Snyder JR، Bensen JT، Hirakawa S، Rich SS، Freedman BI، Bowden DW (August 2001). "A high-resolution 6.0-megabase transcript map of the type 2 diabetes susceptibility region on human chromosome 20". Genomics. 76 (1-3): 45-57. PMID 11549316. doi:10.1006/geno.2001.6584. ...
The following are some of the gene count estimates of human chromosome 16. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project (CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes.[5]. ...
The following are some of the gene count estimates of human chromosome 3. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project (CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes.[5] ...
암펠로데스모스(ampelodesmos, 학명: Ampelodesmos mauritanicus 암펠로데스모스 마우리타니쿠스[*])는 포아풀아과의 단형 족인 암펠로데스모스족(ampelodesmos族, 학명: Ampelodesmeae 암펠로데스메아이[*])의 단형 속인 암펠로데스모스속(ampelodesmos屬, 학명: Ampelodesmos 암펠로데스모스[*])에 속하는 유일한 종이다.[1][2][3][4][5][6] 고대에 나래새족과 산기장족 선조들 사이의 잡종의 일종으로 종분화를 통해 분화한 것으로 추정하고 있다.[6] 암펠로데스모스는 넓게 군락을 지어 자라는 다년생 다발풀의 일종으로 지중해 지역에서 자생한다. 자생지 분포 지역 외부로 도입되어 관상용으로 자배된다. 원추 꽃차례가 고개를 숙이며 키가 60cm에 달한다. 자생지에서 돗자리와 비, 바느질 실 등의 재료로 사용되었다. 지중해 분지 바깥의 비자생 생태계에서는 외래 침입종이 될 수 있다.[7][8][9] ...
Heterogeneous gene expression from the inactive X chromosome: An X-linked gene that escapes X inactivation in some human cell ... a study of 305 patients with sex chromosome aneuploidy. Am J Med Genet. 2010;152:1206-12 ... The above-mentioned karyotype arises as a consequence of a failure in disjunction of paired X-chromosomes during the first or ... Methylation-specific PCR allows for fast diagnosis of X chromosome disomy and reveals skewed inactivation of the X chromosome ...
Chromosome A chromosome is a structure that occurs within cells and that contains the cells genetic material. That genetic ... Humans possess twenty-three pairs including the sex chromosomes. A male has an X and a Y sex chromosome, whereas a female has ... The most common mistake in humans is called aneuploidy. This occurs when an offspring has an extra or a missing chromosome. ... With 46 chromosomes, humans fall well within this average.. The 46 human chromosomes are arranged in 23 pairs. One pair of the ...
The normal amount for humans is 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look ... The 23rd pair, the sex chromosomes, decides female and male. Most people are not aware that aneuploidy is the cause of greater ... Aneuploidy is the term used to describe any embryo with either too many or too few chromosomes. ... The purpose of PGS is to analyze, select and transfer only embryos that have the appropriate number of chromosomes. Next ...
The typical number of chromosomes in each human cell is 46. These include 24 pairs of "autosomes" (which refers to all ... About X and Y Chromosome Variations. X and Y Chromosome Variations, also known medically as Sex Chromosome Aneuploidy (SCA), ... That means the genetic signature for a person with 46 chromosomes is either 46,XY (males), or 46,XX (females). ... Sex chromosome aneuploidy is not inherited. The extra chromosome is the result of an error that occurs in cell division when ...
Apart from sex chromosome disorders, most cases of aneuploidy result in death of the developing fetus (miscarriage); the most ... The human nucleotide diversity is estimated to be 0.1% to 0.4% of base pairs. A difference of 1 in 1,000 amounts to ... According to a 2000 study of Y-chromosome sequence variation, human Y-chromosomes trace ancestry to Africa, and the descendants ... No two humans are genetically identical. On average, in DNA sequence, each human is 99.5% similar to any other human. Even ...
... marker chromosome, gross rearrangements and variation in chromosome size. The frequency in human population is thought to be ... Qi, Ji; Fangqing Zhao (June 2011). "inGAP-sv: a novel scheme to identify and visualize structural variation from paired end ... Microscopic means that it can be detected with optical microscopes, such as aneuploidies, ... Wyandt, H. E.; Tonk, V. S. (2004). Atlas of Human Chromosome Heteromorphisms. Netherlands: Kluwer Academic. ISBN 978-90-481- ...
It wasnt until 1956, when I was 11 years old, that scientists discovered how many chromosomes humans had (23 pairs for a total ... Chromosome abnormalities can also occur in the sex chromosomes. Usually a female has two X chromosomes (XX) and a male has one ... Tagged in: aneuploidy, cell-free DNA testing, chromosomes., Down syndrome, prenatal testing, trisomy ... and it also detects fetal sex and sex chromosome aneuploidy. Three cell-free DNA tests are currently on the market with prices ...
Normally, there are 23 pairs of chromosomes in each human cell, for a total of 46 chromosomes. Each of these chromosomes has a ... Twenty-three chromosomes usually come from the mother and are contained in the egg, and 23 chromosomes come from the father, ... Such abnormalities in chromosome number are called aneuploidy. A common example is an extra chromosome number 21 found in Down ... study for all 23 pairs of chromosomes in a few cells removed from the embryo on day five of development. The goal of CCS is to ...
Most human cells have 23 pairs of chromosomes. Any deviation from this number can be fatal for cells, and several genetic ... Aneuploidy occurs when cells make errors sorting their chromosomes during cell division. When aneuploidy occurs in embryonic ... For human embryos, extra copies of any chromosome are lethal, with the exceptions of chromosome 21, which produces Down ... Aneuploidy and cancer aggressiveness The researchers found that the chromosomes that are most commonly aneuploid in prostate ...
... the normal human chromosome number. The human chromosome complement consists of 23 pairs of varying size and shape. Normally, ... Abnormalities in chromosome number (a condition known as aneuploidy) in humans are usually attributed to maternal origin and ... Jacobs, P. A. The William Allan MemorialAward Address: Human Population Cytogenetics: The First Twenty-Five Years. American ... Human females have two X chromosomes, and males have one X and one Y chromosome. Errors in chromosome patterns can occur during ...
16) Divergence through the number that is normal of and Y chromosomes, called sex chromosome aneuploidy (SCA), makes up about ... Demonstrably, you will find not just females that are XX and men that are XY, but instead, there was a selection of chromosome ... Humans are born with 46 chromosomes in 23 pairs.. Home Gender and Genetics: Humans are born with 46 chromosomes in 23 pairs. ... Humans have actually 23 pairs of chromosomes, one 1 / 2 of each set inherited from each moms and dad. The Y chromosome is tiny ...
16) Divergence through the number that is normal of and Y chromosomes, called sex chromosome aneuploidy (SCA), is the reason ... Plainly, you will find not just females who will be XX and men who will be XY, but instead, there clearly was a selection of ... Humans have actually 23 pairs of chromosomes, one half each set inherited from each moms and dad. The Y chromosome is tiny, ... The Y chromosome will act as a principal inducer of male phenotype and folks having four X chromosomes plus one Y chromosome ( ...
As this karyotype displays, a diploid human cell contains 22 pairs of homologous chromosomes and 2 sex chromosomes.. Section ... It follows from the definition that male humans have a monoploid number of 22, while females have 23 (including one X-X pair). ... The term "aneuploidy" refers to an abnormal numbers of nuclear chromosomes; extra-nuclear genomes are not counted. Its ... chromosomes." For example, the number of homologous sets of chromosomes in humans is 23 if one considers a "set" to be one pair ...
Humans are born with 46 chromosomes in 23 pairs. The X and Y chromosomes determine a persons sex. Most women are 46XX and most ... Aneuploidy occurs in at least 5% of all pregnancies and is the most commonly recognized chromosome abnormality in humans. ... Similarly some females are also born 46XY due to mutations in the Y chromosome. Clearly, there are not only females who are XX ... Divergence from the normal number of X and Y chromosomes, called sex chromosome aneuploidy (SCA), accounts for approximately ...
From Largest (chromosome pair 1) to smallest (chromosome pair 22). 23rd pair is the sex chromosomes ... A chromosome number followed by a p/q and a +/- indicate which chromosome arm is affected. Eg.. 46,XX 4p- ... What is an Aneuploidy? An abnormal number of chromosomes that is not divisible by haploid number (23 in humans) ... Loss of one chromosome i.e. One chromosome pair exists as a single chromosome ...
... each cell in the human embryo should contain 23 pairs of chromosomes (22 pairs of chromosomes and one pair of sex chromosomes ... Abnormal mouse embryos are relatively unusual, so the team used a molecule known as reversine to induce aneuploidy. In embryos ... Abnormal cells with numerical and/or structural anomalies of chromosomes have been observed in as many as 80-90% of human early ... British Researchers Seek to Use New Genome Editing Techniques on Human Embryos. The knowledge acquired from the research may ...
This is called aneuploidy. Normally, an embryo should have 46 chromosomes or, more precisely - 23 pairs of chromosomes. In two- ... Normal human embryos contain 23 pairs of chromosomes. Commonly however, embryos will contain too many or too few chromosomes. ... These abnormalities are known as aneuploidies. Embryo chromosome abnormalities such as aneuploidies are thought to be ... PGS involves removing a cell or two from the early stages of a growing embryo and analyzing the number of chromosomes. ...
It is normal for a cell to contain 22 pairs of chromosomes plus the sex chromosomes, either XX for females or XY for males. ... a condition termed aneuploidy. It has been known for some time that a significant number of human embryos have the wrong number ... Chromosome screening of embryos in IVF. The laboratory at Concept Fertility Centre has set up a new test called 24sure that ... Will the embryoscope identify embryos with the correct number of chromosomes?. No. At present the most definitive way to screen ...
Priemer, D. S., Vortmeyer, A. O., Zhang, S., Chang, H. Y., Curless, K. L. & Cheng, L., Jul 2019, In : Human pathology. 89, p. ... Human pathology. 90, p. 27-36 10 p.. Research output: Contribution to journal › Article ... Human pathology. 93, p. 6-15 10 p.. Research output: Contribution to journal › Article ... 20, 4, p. 546-551 6 p.. Research output: Contribution to journal › Article ...
Numerical and structural chromosome aberrations induced by etoposide (VP16) during oocyte maturation of mice: transmission to ... 40 or 60 mg/kg ET 2 h after human chorionic gonadotrophin (HCG). ICR males were paired (1:1) with females immediately after ... also predispose cells to aneuploidy because this enzyme is needed for removing regions of DNA catenation prior to chromosome ... Numerical and structural chromosome aberrations induced by etoposide (VP16) during oocyte maturation of mice: transmission to ...
MeSH-major] Aneuploidy. Chromosomes, Human, Pair 8 / genetics. Leukemia, Myeloid / genetics. Myelodysplastic Syndromes / ... twenty ten [shown] Results per page: 5. 10. 20. 50. 100. 200. 500. [expand/collapse] show these sections expanded by default: ... Chromosome Aberrations. Chromosome Banding. Chromosome Breakage. Chromosome Deletion. Chromosomes, Human, Pair 11 / genetics. ... MeSH-major] Chromosomes, Human, Pair 17. Chromosomes, Human, Pair 6. Leukemia, Myeloid, Acute / genetics. Translocation, ...
Human females are typically XX; males are typically XY. The remaining pairs of chromosome are found in both sexes and are ... except in the case of certain types of Y chromosome aneuploidy), that allele is always expressed regardless of whether it is ... In humans and other mammal species, sex is determined by two sex chromosomes called the X chromosome and the Y chromosome. ... Most animals and some plants have paired chromosomes, and are described as diploid. They have two versions of each chromosome, ...
The human genome is sorted into twenty-three pairs of chromosomes. Genetic conditions are caused by unwanted changes in the ... Sex chromosome aneuploidies are genetic diseases caused by the presence or absence of a sex chromosome. The 23rd pair of ... Women have two X chromosomes and men have one X and one Y chromosome. There are four major sex chromosome aneuploidies:. * ... SEX CHROMOSOME ANEUPLOIDIES (only in single pregnancies). 45, X. Turner syndrome. 47, XXX. Triple X syndrome. 47, XXY. ...
... the most common pair is XX. On each chromosome are hundreds of gene pairs. Genes are the blueprint for human growth and ... Aneuploidy means there is the wrong number of chromosomes. This can be too many or too few. Trisomies 13, 18 and 21 are ... Typically there are 22 non-sex chromosome pairs called autosomes, and one sex chromosome pair. If you are male, the most common ... Normally each individual has 46 chromosomes in every cell. Most fetuses receive 23 chromosomes from each parent. Chromosomes ...
Sex chromosomes X and Y are the 23rd pair in humans. There are two Xs in females but only a single X in males, whereas the ... Chromosome abnormalities. Chromosome abnormalities may be numerical (aneuploidy: monosomy or trisomy) or structural: deletion, ... such as XX male syndrome and maybe XY female type gonadal dysgenesis). Interleukin-9 receptor (IL9R) gene is located at Xq28 ... Chromosomes differ in their sizes. The smallest human chromosome is chromosome 21 (50 Mb) and the largest one is chromosome 1 ( ...
  • When clinical patterns associated with abnormal numbers of sex chromosomes were discovered in the 1930s and 1940s, these conditions were named after the physicians who first described them. (scienceclarified.com)
  • Este sitio web proporciona servicios de apoyo, una hoja informativa, e información sobre el síndrome Klinefelter y otras variaciones en cromosomas sexuales. (hostingtest2.space)