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)Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.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.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.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.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, Pair 1: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.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, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.Chromosome Segregation: The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.Chromosomes, Human, Pair 7: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 11: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.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.Chromosome Deletion: Actual loss of portion of a chromosome.Chromosomes, Human, Pair 9: A specific pair of GROUP C CHROMSOMES of the human chromosome classification.Chromosomes, Human, Pair 21: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Chromosomes, Plant: Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.Chromosomes, Fungal: Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.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.Chromosomes, Human, Pair 2: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.Chromosomes, Human, Pair 16: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 22: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Chromosome Pairing: The alignment of CHROMOSOMES at homologous sequences.Chromosomes, Mammalian: Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of MAMMALS.Chromosomes, Human, Pair 13: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 4: A specific pair of GROUP B CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 10: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.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, Human, Pair 8: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 19: A specific pair of GROUP F CHROMOSOMES 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, 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.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, 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 12: A specific pair of GROUP C CHROMOSOMES 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.Chromosomes, Human, Pair 5: One of the two pairs of human chromosomes in the group B class (CHROMOSOMES, HUMAN, 4-5).Chromosomes, Human, Pair 15: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Karyotyping: Mapping of the KARYOTYPE of a cell.Chromosomes, Human, Pair 14: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 18: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.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.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.Chromosomes, Human, Pair 20: A specific pair of GROUP F 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, 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.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.Chromosome Breakage: A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.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.Ring Chromosomes: Aberrant chromosomes with no ends, i.e., circular.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.Genetic Markers: A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.Chromosome Positioning: The mechanisms of eukaryotic CELLS that place or keep the CHROMOSOMES in a particular SUBNUCLEAR SPACE.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.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.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.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Chromosomes, Insect: Structures within the CELL NUCLEUS of insect cells containing DNA.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.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.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 Structures: Structures which are contained in or part of CHROMOSOMES.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.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).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.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.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.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."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.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.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.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).Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.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.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.Trisomy: The possession of a third chromosome of any one type in an otherwise diploid cell.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.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.Kinetochores: Large multiprotein complexes that bind the centromeres of the chromosomes to the microtubules of the mitotic spindle during metaphase in the cell cycle.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)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.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).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.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.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.Chromosomal Instability: An increased tendency to acquire CHROMOSOME ABERRATIONS when various processes involved in chromosome replication, repair, or segregation are dysfunctional.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.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.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.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Chromosome Fragility: Susceptibility of chromosomes to breakage leading to translocation; CHROMOSOME INVERSION; SEQUENCE DELETION; or other CHROMOSOME BREAKAGE related aberrations.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Quantitative Trait Loci: Genetic loci associated with a QUANTITATIVE TRAIT.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.Chromosome Duplication: An aberration in which an extra chromosome or a chromosomal segment is made.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.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.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.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.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.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).Diploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.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)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.Heterozygote: An individual having different alleles at one or more loci regarding a specific character.Abnormalities, MultiplePolytene Chromosomes: Extra large CHROMOSOMES, each consisting of many identical copies of a chromosome lying next to each other in parallel.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)Polyploidy: The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.DNA Replication: The process by which a DNA molecule is duplicated.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.Prophase: 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.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).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.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.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.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.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.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.Genetic Variation: Genotypic differences observed among individuals in a population.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.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)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.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.Cosmids: Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.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.)Gene Rearrangement: The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.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.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).Monosomy: The condition in which one chromosome of a pair is missing. In a normally diploid cell it is represented symbolically as 2N-1.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.Spermatocytes: 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, X-Linked: Genes that are located on the X CHROMOSOME.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.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.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Genes, Dominant: Genes that influence the PHENOTYPE both in the homozygous and the heterozygous state.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.Saccharomyces cerevisiae: 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.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.DNA Transposable Elements: 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.Genetic Predisposition to Disease: A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.Philadelphia Chromosome: 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).Genes, Recessive: Genes that influence the PHENOTYPE only in the homozygous state.Azure Stains: PHENOTHIAZINES with an amino group at the 3-position that are green crystals or powder. They are used as biological stains.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Chromosomes, Archaeal: Structures within the nucleus of archaeal cells consisting of or containing DNA, which carry genetic information essential to the cell.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.Chromosome Breakpoints: The locations in specific DNA sequences where CHROMOSOME BREAKS have occurred.Contig Mapping: Overlapping of cloned or sequenced DNA to construct a continuous region of a gene, chromosome or genome.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)Genome: The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.Ploidies: The degree of replication of the chromosome set in the karyotype.Homozygote: An individual in which both alleles at a given locus are identical.Haploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented once. Symbol: N.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.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.Escherichia coli: 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.Genetic Loci: Specific regions that are mapped within a GENOME. Genetic loci are usually identified with a shorthand notation that indicates the chromosome number and the position of a specific band along the P or Q arm of the chromosome where they are found. For example the locus 6p21 is found within band 21 of the P-arm of CHROMOSOME 6. Many well known genetic loci are also known by common names that are associated with a genetic function or HEREDITARY DISEASE.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.Sex Chromatin: In the interphase nucleus, a condensed mass of chromatin representing an inactivated X chromosome. Each X CHROMOSOME, in excess of one, forms sex chromatin (Barr body) in the mammalian nucleus. (from King & Stansfield, A Dictionary of Genetics, 4th ed)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)Gene Duplication: Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.Hybridization, Genetic: The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid.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.Drosophila: 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.Genes, Lethal: 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.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.Intellectual Disability: 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)Genes, Bacterial: The functional hereditary units of BACTERIA.Genome, Plant: The genetic complement of a plant (PLANTS) as represented in its DNA.DNA, Neoplasm: DNA present in neoplastic tissue.Chromosomes, Artificial: DNA constructs that are composed of, at least, elements such as a REPLICATION ORIGIN; TELOMERE; and CENTROMERE, that are required for successful replication, propagation to and maintenance in progeny cells. In addition, they are constructed to carry other sequences for analysis or gene transfer.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.Syndrome: A characteristic symptom complex.Pachytene Stage: The stage in the first meiotic prophase, following ZYGOTENE STAGE, when CROSSING OVER between homologous CHROMOSOMES begins.Microtubules: 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.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.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.Histones: 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.DNA, Fungal: Deoxyribonucleic acid that makes up the genetic material of fungi.Genes, Y-Linked: Genes that are located on the 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.Triticum: 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.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.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.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.Sex Determination Processes: The mechanisms by which the SEX of an individual's GONADS are fixed.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)Genes, Insect: The functional hereditary units of INSECTS.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.Meiotic Prophase I: The prophase of the first division of MEIOSIS (in which homologous CHROMOSOME SEGREGATION occurs). It is divided into five stages: leptonema, zygonema, PACHYNEMA, diplonema, and diakinesis.Quantitative Trait, Heritable: A characteristic showing quantitative inheritance such as SKIN PIGMENTATION in humans. (From A Dictionary of Genetics, 4th ed)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.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.Genetic Heterogeneity: The presence of apparently similar characters for which the genetic evidence indicates that different genes or different genetic mechanisms are involved in different pedigrees. In clinical settings genetic heterogeneity refers to the presence of a variety of genetic defects which cause the same disease, often due to mutations at different loci on the same gene, a finding common to many human diseases including ALZHEIMER DISEASE; CYSTIC FIBROSIS; LIPOPROTEIN LIPASE DEFICIENCY, FAMILIAL; and POLYCYSTIC KIDNEY DISEASES. (Rieger, et al., Glossary of Genetics: Classical and Molecular, 5th ed; Segen, Dictionary of Modern Medicine, 1992)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.Sex Chromosome Disorders of Sex Development: Congenital conditions of atypical sexual development associated with abnormal sex chromosome constitutions including MONOSOMY; TRISOMY; and MOSAICISM.

The mouse Spo11 gene is required for meiotic chromosome synapsis. (1/430)

The Spo11 protein initiates meiotic recombination by generating DNA double-strand breaks (DSBs) and is required for meiotic synapsis in S. cerevisiae. Surprisingly, Spo11 homologs are dispensable for synapsis in C. elegans and Drosophila yet required for meiotic recombination. Disruption of mouse Spo11 results in infertility. Spermatocytes arrest prior to pachytene with little or no synapsis and undergo apoptosis. We did not detect Rad51/Dmc1 foci in meiotic chromosome spreads, indicating DSBs are not formed. Cisplatin-induced DSBs restored Rad51/Dmc1 foci and promoted synapsis. Spo11 localizes to discrete foci during leptotene and to homologously synapsed chromosomes. Other mouse mutants that arrest during meiotic prophase (Atm -/-, Dmc1 -/-, mei1, and Morc(-/-)) showed altered Spo11 protein localization and expression. We speculate that there is an additional role for Spo11, after it generates DSBs, in synapsis.  (+info)

Chromosome synapsis defects and sexually dimorphic meiotic progression in mice lacking Spo11. (2/430)

Spo11, a protein first identified in yeast, is thought to generate the chromosome breaks that initiate meiotic recombination. We now report that disruption of mouse Spo11 leads to severe gonadal abnormalities from defective meiosis. Spermatocytes suffer apoptotic death during early prophase; oocytes reach the diplotene/dictyate stage in nearly normal numbers, but most die soon after birth. Consistent with a conserved function in initiating meiotic recombination, Dmc1/Rad51 focus formation is abolished. Spo11(-/-) meiocytes also display homologous chromosome synapsis defects, similar to fungi but distinct from flies and nematodes. We propose that recombination initiation precedes and is required for normal synapsis in mammals. Our results also support the view that mammalian checkpoint responses to meiotic recombination and/or synapsis defects are sexually dimorphic.  (+info)

M31 and macroH2A1.2 colocalise at the pseudoautosomal region during mouse meiosis. (3/430)

Progression through meiotic prophase is associated with dramatic changes in chromosome condensation. Two proteins that have been implicated in effecting these changes are the mammalian HP1-like protein M31 (HP1beta or MOD1) and the unusual core histone macroH2A1.2. Previous analyses of M31 and macroH2A1.2 localisation in mouse testis sections have indicated that both proteins are components of meiotic centromeric heterochromatin and of the sex body, the transcriptionally inactive domain of the X and Y chromosomes. This second observation has raised the possibility that these proteins co-operate in meiotic sex chromosome inactivation. In order to investigate the roles of M31 and macroH2A1.2 in meiosis in greater detail, we have examined their localisation patterns in surface-spread meiocytes from male and female mice. Using this approach, we report that, in addition to their previous described staining patterns, both proteins localise to a focus within the portion of the pseudoautosomal region (PAR) that contains the steroid sulphatase (Sts) gene. In light of the timing of its appearance and of its behaviour in sex-chromosomally variant mice, we suggest a role for this heterochromatin focus in preventing complete desynapsis of the terminally associated X and Y chromosomes prior to anaphase I.  (+info)

Evidence for meiotic spindle checkpoint from analysis of spermatocytes from Robertsonian-chromosome heterozygous mice. (4/430)

Mice heterozygous for Robertsonian centric fusion chromosomal translocations frequently produce aneuploid sperm. In this study RBJ/Dn x C57BL/6J F1 males, heterozygous for four Robertsonian translocations (2N=36), were analyzed to determine effects on germ cells of error during meiosis. Analysis of sperm by three color fluorescence in situ hybridization revealed significantly elevated aneuploidy, thus validating Robertsonian heterozygous mice as a model for production of chromosomally abnormal gametes. Primary spermatocytes from heterozygous males exhibited abnormalities of chromosome pairing in meiotic prophase and metaphase. In spite of prophase abnormalities, the prophase/metaphase transition occurred. However, an increased frequency of cells with misaligned condensed chromosomes was observed. Cytological analysis of both young and adult heterozygous mice revealed increased apoptosis in spermatocytes during meiotic metaphase I. Metaphase spermatocytes with misaligned chromosomes accounted for a significant proportion of the apoptotic spermatocytes, suggesting that a checkpoint process identifies aberrant meioses. Immunofluorescence staining revealed that kinetochores of chromosomes that failed to align on the spindle stained more intensely for kinetochore antigens CENP-E and CENP-F than did aligned chromosomes. Taken together, these observations are consistent with detection of malattached chromosomes by a meiotic spindle checkpoint mechanism that monitors attachment and/or congression of homologous chromosome pairs. However, the relatively high frequency of gametic aneuploidy suggests that the checkpoint mechanism does not efficiently eliminate all germ cells with chromosomal abnormalities.  (+info)

Checkpoints: chromosome pairing takes an unexpected twist. (5/430)

When meiotic cells complete S phase, homologous chromosomes pair, synapse and undergo recombination. A checkpoint protein is somehow required for meiotic chromosome pairing in C. elegans, thus providing a direct link between S phase and the rest of the meiotic program.  (+info)

Nucleolus-associated telomere clustering and pairing precede meiotic chromosome synapsis in Arabidopsis thaliana. (6/430)

The intranuclear arrangements of centromeres and telomeres during meiotic interphase and early prophase I of meiosis in Arabidopsis thaliana were analysed by fluorescent in situ hybridisation to spread pollen mother cells and embryo-sac mother cells. Meiocyte identification, staging and progression were established by spreading and sectioning techniques, including various staining procedures and bromodeoxyuridine labeling of replicating DNA. Centromere regions of Arabidopsis are unpaired, widely dispersed and peripherally located in nuclei during meiotic interphase, and they remain unpaired and unassociated throughout leptotene. Eventually they associate pairwise during zygotene, as part of the nucleus-wide synapsis of homologous chromosomes. Telomeres, by contrast, show a persistent association with the nucleolus throughout meiotic interphase. Variation in telomere signal number indicates that telomeres undergo pairing during this interval, preceding the onset of general chromosome synapsis. During leptotene the paired telomeres lose their association with the nucleolus and become widely dispersed. As the chromosomes synapse during zygotene, the telomeres reveal a loose clustering within one hemisphere, which may represent a degenerate or relic bouquet configuration. We propose that in Arabidopsis the classical leptotene/zygotene bouquet is absent and is replaced functionally by nucleolus-associated telomere clustering.  (+info)

The mouse meiotic mutation mei1 disrupts chromosome synapsis with sexually dimorphic consequences for meiotic progression. (7/430)

mei1 (meiosis defective 1) is the first meiotic mutation in mice derived by phenotype-driven mutagenesis. It was isolated by using a novel technology in which embryonic stem (ES) cells were chemically mutagenized and used to generate families of mice that were screened for infertility. We report here that mei1/mei1 spermatocytes arrest at the zygotene stage of meiosis I, exhibiting failure of homologous chromosomes to properly synapse. Notably, RAD51 failed to associate with meiotic chromosomes in mutant spermatocytes, despite evidence for the presence of chromosomal breaks. Transcription of genes that are markers for the leptotene and zygotene stages, but not genes that are markers for the pachytene stage, was observed. mei1/mei1 females are sterile, and their oocytes also show severe synapsis defects. Nevertheless, unlike arrested spermatocytes, a small number of mutant oocytes proved capable of progressing to metaphase I and attempting the first meiotic division. However, their chromosomes were unpaired and were not organized properly at the metaphase plate or along the spindle fibers during segregation. mei1 was genetically mapped to chromosome (Chr) 15 in an interval that is syntenic to human Chr 22q13. This region, which has been completely sequenced, contains no known homologs of genes specifically required for meiosis in model organisms. Thus, mei1 may be a novel meiotic gene.  (+info)

Eco1 is a novel acetyltransferase that can acetylate proteins involved in cohesion. (8/430)

Cohesion between sister chromatids is established during S phase and maintained through G2 phase until it is resolved in anaphase (for review, see [1-3]). In Saccharomyces cerevisiae, a complex consisting of Scc1, Smc1, Smc3, and Scc3 proteins, called "cohesin," mediates the connection between sister chromatids. The evolutionary conserved yeast protein Eco1 is required for establishment of sister chromatid cohesion during S phase but not for its further maintenance during G2 or M phases or for loading the cohesin complex onto DNA. We address the molecular functions of Eco1 with sensitive sequence analytic techniques, including hidden Markov model domain fragment searches. We found a two-domain architecture with an N-terminal C2H2 Zn finger-like domain and an approximately 150 residue C-terminal domain with an apparent acetyl coenzyme A binding motif (http://mendel.imp.univie.ac.at/SEQUENCES/ECO1/). Biochemical tests confirm that Eco1 has the acetyltransferase activity in vitro. In vitro Eco1 acetylates itself and components of the cohesin complex but not histones. Thus, the establishment of cohesion between sister chromatids appears to be regulated, directly or indirectly, by a specific acetyltransferase.  (+info)

We report the discovery of a checkpoint that monitors synapsis between homologous chromosomes to ensure accurate meiotic segregation. Oocytes containing unsynapsed chromosomes selectively undergo apoptosis even if a germline DNA damage checkpoint is inactivated. This culling mechanism is specifically activated by unsynapsed pairing centers, cis-acting chromosome sites that are also required to promote synapsis in Caenorhabditis elegans. Apoptosis due to synaptic failure also requires the C. elegans homolog of PCH2, a budding yeast pachytene checkpoint gene, which suggests that this surveillance mechanism is widely conserved.. ...
Ministry of Human Resource Development (MHRD) under its National Mission on Education through Information and Communication Technology (NMEICT) has initiated the National Digital Library of India (NDL India) pilot project to develop a framework of virtual repository of learning resources with a single-window search facility. Filtered and federated searching is employed to facilitate focused searching so that learners can find out the right resource with least effort and in minimum time. NDL India is designed to hold content of any language and provides interface support for leading Indian languages. It is being arranged to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular form of access devices and differently-abled learners. It is being developed to help students to prepare for entrance and competitive examination, to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to ...
Plays a key role in meiotic progression. Regulates 3 different functions during meiosis: ensures that sufficient numbers of processed DNA double-strand breaks (DSBs) are available for successful homology search by increasing the steady-state numbers of single-stranded DSB ends. Promotes synaptonemal-complex formation independently of its role in homology search. Plays a key role in the male mid-pachytene checkpoint and the female meiotic prophase checkpoint: required for efficient build-up of ATR activity on unsynapsed chromosome regions, a process believed to form the basis of meiotic silencing of unsynapsed chromatin (MSUC) and meiotic prophase quality control in both sexes.
During metaphase I, the homologous chromosomes are arranged in the center of the cell with the kinetochores facing opposite poles. The homologous pairs orient themselves randomly at the equator. For example, if the two homologous members of chromosome 1 are labeled a and b, then the chromosomes could line up a-b, or b-a. This is important in determining the genes carried by a gamete, as each will only receive one of the two homologous chromosomes. Recall that homologous chromosomes are not identical. They contain slight differences in their genetic information, causing each gamete to have a unique genetic makeup.. This randomness is the physical basis for the creation of the second form of genetic variation in offspring. Consider that the homologous chromosomes of a sexually reproducing organism are originally inherited as two separate sets, one from each parent. Using humans as an example, one set of 23 chromosomes is present in the egg donated by the mother. The father provides the other set ...
Homologous chromosomes are two pieces of DNA within a diploid organism which carry the same genes, one from each parental source.
4. I asked the wrong question. How do the homologous chromosomes pair up (mate/join)? How do they recognize that chromosome with whom to pair? If there are different genes on different chromosomes, I assume that this pairing would have to have 2 chromosomes with the same set of genes. Is this the 1 and the 2 of the 2n (one from the mother side, one from the father side)? Thus each pair of homologous chromosomes have a total of 4 sister chromatids, 2 on each of the homologous chromosomes. How the chromosomes pair correctly is my biggest stumbling point ...
Complete information for MEIOB gene (Protein Coding), Meiosis Specific With OB Domains, including: function, proteins, disorders, pathways, orthologs, and expression. GeneCards - The Human Gene Compendium
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We want to hear from you!. Like what we do? Want to get involved? Curious about classes, workshops, cabarets, or other happenings?. The Synapsis Collective welcomes new members and is happy to perform at your event! ...
The synapsis is a 4×4 pushbutton matrix that offers performative control of the Bit Ranger.. There are 8 patch points connected to 4 rows (ABCD) and 4 columns (1234) of buttons. Pressing button A1 connects point A to point 1. A2 connects A to 2. B2 connects B to 2 and so on.. Package includes:. ...
The synapsis is a 4×4 pushbutton matrix that offers performative control of the Bit Ranger.. There are 8 patch points connected to 4 rows (ABCD) and 4 columns (1234) of buttons. Pressing button A1 connects point A to point 1. A2 connects A to 2. B2 connects B to 2 and so on.. Package includes:. ...
amongst a established of different varieties of a gene. Diploid cells have two homologous chromosomes (a person derived from Each and every parent) and as a consequence two copies of every gene. Within a diploid mobile, a gene will have two alleles, Each individual occupying the exact same placement on homologous chromosomes ...
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Red Hat, el proveedor de soluciones de código abierto líder en el mundo, suscribieron un acuerdo de colaboración regional para el desarrollo de..
Part 2 of the mind bending adventure game, David Carter is again trapped in a series of bizarre rooms which he will need to find some way of escape from.. Yes it\s finally here after 2 years of waiting. Part 3 (the final part) will hopefully take a bit less time. Thanks to everyone who has asked me about this for the past 2 years.. ...
Part 2 of the mind bending adventure game, David Carter is again trapped in a series of bizare rooms which he will need to find some way of escape from.Yes its finally here after 2 years of waiting. Part 3 (the final part) will hopefully take a bit less time. Thanks to everyone who has asked me about this for the past 2 years. ...
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casSAR Dugability of Q03410 | Sycp1 | Synaptonemal complex protein 1 - Also known as SYCP1_RAT, Sycp1, Scp1. Major component of the transverse filaments of synaptonemal complexes, formed between homologous chromosomes during meiotic prophase (PubMed:1464329). Required for normal assembly of the central element of the synaptonemal complexes. Required for normal centromere pairing during meiosis. Required for normal meiotic chromosome synapsis during oocyte and spermatocyte development and for normal male and female fertility. Structural component of synaptonemal complexes (By similarity). Homotetramer that consists of an N-terminal four-helical bundle that bifurcates into two elongated C-terminal dimeric coiled coils. This tetrameric building block potentially self-assembles into a supramolecular zipper-like lattice to mediate meiotic chromosome synapsis. Self-assembly is likely initiated by local proton density at chromosome axis, which is predicted to trigger antiparallel back to back assembly of
The fine structure of bivalents from golden hamster and house cricket spermatocytes has been studied with a whole mount surface-spreading method combined with negative staining. The elements of the synaptonemal complex show detail of structure which is absent in other preparative procedures. The transverse filaments found in the central region of the synaptonemal complex from both species are straight and have a similar width, 1 6-1 8 nm These filaments occur mainly in bundles The central element differs in architecture in the two species In hamster bivalents it is formed of longitudinal stretches of filaments 1.6-1 8 nm wide and a small amount of an amorphous material similar to that of the lateral elements In the cricket, the central element contains transverse fibrils which are continuous with the transverse filaments of the central region, and an amorphous material lying mainly along the sides of the central element All of the components of the central region of the synaptonemal complex are ...
This gene encodes a member of the synaptonemal complex, which links homologous chromosomes during prophase I of meiosis. The tripartite structure of the complex is highly conserved amongst metazoans. It consists of two lateral elements and a central region formed by transverse elements and a central element. The protein encoded by this gene localizes to the central element and is required for initiation and elongation of the synapsis. Allelic variants of this gene have been associated with premature ovarian failure and spermatogenic failure. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2016 ...
TY - JOUR. T1 - Essential role of Fkbp6 in male fertility and homologous chromosome pairing in meiosis. AU - Crackower, Michael A.. AU - Kolas, Nadine K.. AU - Noguchi, Junko. AU - Sarao, Renu. AU - Kikuchi, Kazuhiro. AU - Kaneko, Hiroyuki. AU - Kobayashi, Eiji. AU - Kawai, Yasuhiro. AU - Kozieradzki, Ivona. AU - Landers, Rushin. AU - Mo, Rong. AU - Hui, Chi Chung. AU - Nieves, Edward. AU - Cohen, Paula E.. AU - Osborne, Lucy R.. AU - Wada, Teiji. AU - Kunieda, Tetsuo. AU - Moens, Peter B.. AU - Penninger, Josef M.. PY - 2003/5/23. Y1 - 2003/5/23. N2 - Meiosis is a critical stage of gametogenesis in which alignment and synapsis of chromosomal pairs occur, allowing for the recombination of maternal and paternal genomes. Here we show that FK506 binding protein (Fkbp6) localizes to meiotic chromosome cores and regions of homologous chromosome synapsis. Targeted inactivation of Fkbp6 in mice results in aspermic mates and the absence of normal pachytene spermatocytes. Moreover, we identified the ...
To test whether recombination promotes SC formation, we used a panel of yeast spo11 missense mutants that show a range of DSB frequencies. The mutant proteins localized properly to meiotic chromosomes and supported at least some of the normal functions carried out by wild-type Spo11. Two different point mutations that abrogated DSB formation blocked SC formation as severely as a deletion mutation. Our results agree with other studies of the spo11-Y135F mutant in yeast (N. Kleckner and B. Weiner, personal communication and unpublished data; see ref. 34) and an equivalent mutant in S. macrospora (8). We also found that mutants with intermediate DSB defects gave intermediate SC defects. Because several different missense mutations and allele combinations were used, it seems unlikely that we managed fortuitously to covary two independent functions of Spo11. Thus, these findings strongly link the DNA-cleaving activity of Spo11 to its activity in promoting SC formation.. Crossover-Designated ...
Meiotic cells possess surveillance mechanisms or checkpoints that monitor critical meiotic events, such as recombination and chromosome synapsis. Defects in these processes, such as those resulting from the absence of the S. cerevisiae Zip1 protein, activate a meiosis-specific checkpoint network resulting in a delay or arrest of meiotic progression. We are studying this meiotic checkpoint at different levels. Pch2 is an evolutionarily conserved AAA+ ATPase initially discovered as a checkpoint protein required for the zip1-induced meiotic arrest in budding yeast. Pch2 impacts multiple aspects of meiotic chromosome metabolism, including negative regulation of Hop1 chromosomal abundance. It has been suggested that Pch2 promotes the turnover of the Hop1 protein; thus, the pch2 single mutant exhibits more continuous Hop1 localization along synapsed chromosomes. Interestingly, in the zip1 mutant, when the checkpoint is induced, Pch2 is only detectable at the rDNA region (nucleolus). A special ...
Meiosis, the pair of specialized cell divisions required to convert germline diploid progenitor cells into haploid gametes, is an essential process for sexual reproduction in eukaryotes. After pre-meiotic DNA replication, germ cells enter an extended G2 cell cycle phase, termed meiotic prophase, during which homologous chromosomes pair and interact, and an extensive, cell type-specific transcription program turns on to set up gamete differentiation. The homologs then segregate to different daughter cells, commonly during the first meiotic division, followed by segregation of sister chromatids during meiosis II without an intervening S phase. As in mitosis, the timing of key cell cycle events is choreographed by regulated activation and deactivation of cyclin-dependent kinase (Cdk) complexes, in which cyclins play key roles in regulating the timing and targets of Cdk activity. B-type cyclins in particular are instrumental to negotiating the G2/M transition in both mitosis and meiosis.. The ...
of being passed down.. Nevertheless, the large breeding pedigrees (since the founder population) in advanced mapping populations such as the MAGIC and the DSPR are often unavailable or inaccurate. Moreover, inbreeding by selfing instead of sibling mating is usually adopted in plant population resources such as the MAGIC. The relatively simple hidden Markov model (HMM), implemented in HAPPY (Mott et al. 2000), is thus widely used, since it does not incorporate any pedigree information except the effective number of generations. HAPPY has implemented two extremes: the diploid mode where the ancestral origin processes between two homologous chromosomes are independent and the haploid mode for haploid genomes and for diploid lines where the processes are completely dependent.. The full range of the dependencies of the ancestral origin processes between two homologous chromosomes has been modeled by a continuous-time Markov chain (CTMC) for both autosomes (Zheng et al. 2014) and X chromosomes (Zheng ...
Build: Wed Jun 21 18:33:50 EDT 2017 (commit: 4a3b2dc). National Center for Advancing Translational Sciences (NCATS), 6701 Democracy Boulevard, Bethesda MD 20892-4874 • 301-435-0888. ...
Meiosis 1: Homologous chromosomes pair up and their chromatids wrap around each other. Equivalent portions of the chromatids can be exchanged in crossing over. By the end the homologous pairs have separated with one chromosome from each pair going into one of two daughter ...
The diploid chromosomal number of a cat is 38. If one of the homologous chromosome pairs does not separate during Meiosis I, how many chromosomes can be found in the gametes?. ...
Meiosis has three unique features :. The mechanism of cell division varies in important details in different organism. This is particularly true of chromosomal separation mechanism, which differ substantially in protists and fungi from the process in plants and animals that we will describe here. Meiosis in a diploid organism consists of two rounds of division, mitosis of one. Although meiosis and mitosis have much in common, meiosis has three unique features: synapsis, homologous recombination, and reduction division.. Synapsis :. The first unique feature of meiosis happens early during the first nuclear division. Following chromosome replication, homologous chromosomes, or homologous pair all along their length. The process of forming these complexes of homologous chromosomes is called synapsis.. Homologous Recombination :. The second unique feature of meiosis is that genetic exchange occurs between the homologous chromosomes while they are thus physically joined. The exchange process that ...
Meiosis generates haploid gametes, such as sperm and eggs, from a diploid cell such that a diploid genome is restored upon fertilization. The proper segregation...
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Gorlov, I.P.; Ladygina, T.Y.; Borodin, P.M., 1990: Synapsis and recombination in mice homozygous for a double insertion of a homogenously stained region of chromosome No. 1
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A protein structure (synaptonemal complex) forms between the homologous chromosomes in the presence of the step-2 enzyme modified with SUMO. If the step-2 enzyme cannot be modified with SUMO, the complex is completely absent.
The end products of meiosis are gametes, which are cells with half the chromosome amount of normal cells. These genes are the same as ones found in the parent cells, but they have a different...
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mitosis and meiosis are both incredibly well conserved in almost all higher organisms studied. given the degree of evolutionary time that has passed to optimise these processes there will be few if any pressures for change. most if not all mutations will tend to make the processes less efficient and this will be selected against.. That said, it is possible that one or more new mutations might arise at some point in the future that could make the processes more efficient.. ...
one of a established of different sorts of a gene. Diploid cells have two homologous chromosomes (one particular derived from each father or mother) and as a consequence two copies of every gene. Within a diploid cell, a gene should have two alleles, Just about every occupying the identical placement on homologous chromosomes ...
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Were going to create a store using React and Meiosis. Meiosis is not a library, you cant import it. Its a powerful pattern to manage state and it works well…
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Match each meiosis event with the phase in which it occurs. Choose your level! Level 3 has the most matches to complete in the shortest time ...
মিয়োসিস বা মায়োসিস ( ইংরেজী-meiosis) এক বিশেষ ধরণের কোষ বিভাজন প্রক্রিয়া যাতে মাতৃকোষের নিউক্লিয়াসটি উপর্যুপরি দুবার বিভাজিত হলেও ক্রোমোসোমের বিভাজন ঘটে মাত্র একবার, ফলে অপত্য কোষে ক্রোমোসোমের সংখ্যা অর্ধেক হয়ে যায়। ১৮৮৭ খ্রিষ্টাব্দে বোভেরী (Boveri) সর্বপ্রথম গোল কৃমির জননাঙ্গে এরূপ কোষবিভাজন প্রত্যক্ষ করেন। বিজ্ঞানী স্ট্রাসবুর্গার (Strasburgar) ১৮৮৮ খ্রিষ্টাব্দে সপুষ্পক উদ্ভিদের ...
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Involvement of synaptonemal complex proteins in sex chromosome segregation during marsupial male meiosis. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
Accurate chromosome segregation during meiosis requires that homologous chromosomes pair and become physically connected so that they can orient properly on the meiosis I spindle. These connections are formed by homologous recombination closely integrated with the development of meiosis-specific, higher-order chromosome structures. The yeast Pch2 protein has emerged as an important factor with roles in both recombination and chromosome structure formation, but recent analysis suggested that TRIP13, the mouse Pch2 ortholog, is not required for the same processes. Using distinct Trip13 alleles with moderate and severe impairment of TRIP13 function, we report here that TRIP13 is required for proper synaptonemal complex formation, such that autosomal bivalents in Trip13-deficient meiocytes frequently displayed pericentric synaptic forks and other defects. In males, TRIP13 is required for efficient synapsis of the sex chromosomes and for sex body formation. Furthermore, the numbers of crossovers and ...
Meiotic chromosome segregation must occur with high fidelity in order to prevent the generation of deleterious aneuploidies. In meiosis I, homologous chromosomes pair, then migrate to opposite poles of the spindle. This process uses a collection of unique structures and mechanisms that have yet to be thoroughly characterized. To acquire a collection of informative meiotic mutants, we carried out a novel genetic screen in Saccharomyces cerevisiae. This screen was designed to identify dominant mutants in which meiosis I chromosome segregation occurs with decreased fidelity. One mutant recovered using this screen, SID1-1 (sister disjunction), showed an incidence of spores disomic for a marked chromosome III that was 25-fold greater than the wild-type level. Crossing-over is slightly, but not dramatically, reduced in SID1-1. Both recombinant and nonrecombinant chromosomes segregate with reduced fidelity in the presence of SID1-1. We present evidence that the mutant is defective in sister-chromatid ...
The synaptonemal complex (SC) is a widely conserved structure that mediates the intimate alignment of homologous chromosomes during meiotic prophase and is necessary for proper homolog segregation at meiosis I. immediate proof for SUMOs function in SC set up. A meiotic reduction-of-function stress displays decreased sporulation, abnormal degrees of crossover recombination, and reduced SC assembly. […]. ...
View Notes - mitosis from SCIENCE 3254 at Fort Valley State University. Mitosis and Meiosis are both forms of cellular reproduction. There are several similarities and differences in both processes.
The cell cycle process in which the synaptonemal complex is formed. This is a structure that holds paired chromosomes together during prophase I of meiosis and that promotes genetic recombination.
When the homologous chromosomes pair in prophase I of meiosis, the genes on the chromosomes pair up. The only way this can happen after an inversion is if the homologous pairs form a loop. If a cross-over occurs within this inversion loop, it can lead to loss or gain of DNA. For this reason, people with inversions in their germ cells often have lower fertility. This is because the gametes are damaged. Families that are carriers of inversions may be offered genetic counselling and testing.[1]. ...
can someone help me with mitosis and meiosis?Mitosis consists of 4 different stages. - Prophase Homologous chromosomes pair up and exchange segmen...
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Rec8 is a prominent component of the meiotic prophase chromosome axis that mediates sister chromatid cohesion, homologous recombination and chromosome synapsis. Here, we explore the prophase roles of Rec8. (i) During the ...
... Zygotene is the stage of meiotic prophase which instantly follows the leptotene and during which synapsis of homologous
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Drawing diagrams to show the stages of meiosis resulting in the formation of four haploid cells. [Drawings of the stages of meiosis do not need to include chiasmata. Preparation of microscope slides showing meiosis is challenging and permanent slides should be available in case no cells in meiosis are visible in temporary mounts ...
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Cancer remains one of the main focus areas of translational research as it is predicted that 50% of the population will experience this disease at some point in their lifetime. Even though major progress has been made in cancer diagnosis and treatment it still remains the second leading cause of death with 8.4 million deaths recorded worldwide in 2012. Consequently, understanding the molecular mechanisms behind cancer development and progression is crucial for developing effective treatments and discovering valuable biomarkers.. Meiosis-associated proteins have never been explored in the context of cancer research as their expression is thought to be tightly controlled and restricted to meiotic cells. We have recently discovered that, contrary to accepted knowledge, a group of meiotic proteins is expressed in a variety of human cancer models. More importantly, our analysis of multiple large datasets of patient cancer samples reveals that these proteins are expressed in the majority of cancer ...
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The processes of mitosis and meiosis are what make every living creature unique. HowStuffWorks breaks down the difference between the two.
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Click to open the acitivity (1st document, top left) and you will see 12 pictures showing cells in different phases of meiosis, and 12 labels for identifying phases. ...
We describe a process in meiotic cells of budding yeast in which chromosomes become joined together in pairs at their centromeres independent of chromosomal homology. These centromeric interactions depend on the synaptonemal complex component Zip1. During meiosis in wild-type diploids, centromere couples are initially nonhomologous and then undergo switching until all couples involve homologs. This transition to homologous coupling depends on Spo11, a protein required for the initiation of meiotic recombination. Regions of synaptonemal complex assembled early in meiosis are often centromere-associated. We propose that centromere coupling facilitates homolog pairing and promotes synapsis initiation. ...
The synaptonemal complex (SC) is an evolutionarily conserved structure that mediates synapsis of homologous chromosomes during meiotic prophase I. Previous studies have established that the chromatin of homologous chromosomes is organized in loops that are attached to the lateral elements (LEs) of the SC. The characterization of the genomic sequences associated with LEs of the SC represents an important step toward understanding meiotic chromosome organization and function. To isolate these genomic sequences, we performed chromatin immunoprecipitation assays in rat spermatocytes using an antibody against SYCP3, a major structural component of the LEs of the SC. Our results demonstrated the reproducible and exclusive isolation of repeat deoxyribonucleic acid (DNA) sequences, in particular long interspersed elements, short interspersed elements, long terminal direct repeats, satellite, and simple repeats. The association of these repeat sequences to the LEs of the SC was confirmed by in situ ...
Basigin (BSG) is a multifunctional glycoprotein that plays an important role in male reproduction since male knockout (KO) mice are sterile. The Bsg KO testis lacks elongated spermatids and mature spermatozoa, a phenotype similar to that of alpha-mannosidase IIx (MX) KO mice. MX regulates formation of N-acetylglucosamine (GlcNAc) terminated N-glycans that participate in germ cell-Sertoli cell adhesion. Results showed that Bsg KO spermatocytes displayed normal homologous chromosome synapsis and progression through meiosis. However, only punctate expression of the round spermatid marker SP-10 in the acrosomal granule of germ cells of Bsg KO mice was detected indicating that spermatogenesis in Bsg KO mice was arrested at the early round spermatid stages. We observed a large increase in the number of germ cells undergoing apoptosis in Bsg KO testes. Using lectin blotting, we determined that GlcNAc terminated N-glycans are linked to BSG. GlcNAc terminated N-glycans were significantly reduced in Bsg KO testes
Genomic in situ hybridization (GISH) was used to study the nature of homoeologous chiasma formation in crosses between Triticum durum cv. Creso, homozygous for the ph1c mutation and Thinopyrum bessarabicum. The relative frequencies of wheat/wheat and wheat/Th. bessarabicum chiasma formation were determined. Pairing between apparently non-homologous Th. bessarabicum chromosomes was also observed. The potential of GISH as a tool for analysing homoeologous chiasma formation in wheat/alien hybrids is discussed. ...
Meiosis is a cell division process that produces haploid gametes from diploid cells. Several important meiotic events take place during prophase of meiosis I, most important being homologous chromosome pairing, meiotic recombination and formation of the synaptonemal complex (SC). These processes assure proper segregation of the homologous chromosomes into the haploid germ cells. Improper segregation of the homologos can cause chromosomal abnormality (aneuploidy), which causes various human disorders, notably mental retardation and pregnancy loss.. This thesis focuses on the relationship between recombination and the formation of SCs, aggregates of SC-related materials (polycomplexes) and recombination enzymes during meiosis. We have investigated SC formation in the absence of recombination, nature of polycomplexes and recombination enzymes in relation to the SCs structures and recombination nodules (RNs) in yeast Saccharomyces cerevisiae.. Studies on yeast mutants suggest that the formation of ...
Supplement In genetics, chromomere is one of those beadlike granules arranged in a linear series on the chromosomes of eukaryotes. Chromomeres form from the local coiling of a continuous DNA thread. They become more distinct during prophase of both mitosis and meiosis. In meiosis, they are evident as early as the leptotene phase of prophase I especially because the chromosomes are starting to get condensed at this stage. In the next stage, i.e. zygotene, wherein the homologous chromosomes pair up in pairs, the chromomeres aid the homologous chromosomes to align with each other and form homologous rough pairing. Chromomeres contain genes and the arrangement of chromomere structure may be applied in controlling gene expression. Maps of chromomere structure may be made to be used for genetic as well as for evolutionary studies. They may prove useful in locating genes on a chromosome and in analyzing chromosomal aberrations. In anatomy, chromomere pertains to the central part of a blood platelet. It ...
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The most important biological role of meiosis compared with asexual reproduction is providing genetic diversity of individuals as a result of mixing of paternal and maternal genes in the gamete. This is achieved in two ways.. Firstly, in the first division of meiosis the distribution of paternal and maternal chromosomes into the daughter cells is random, which results in gametes bearing different combinations of parental chromosomes (Smith and Nicolas 204). The second fundamental mechanism for the maintenance of genetic diversity is that in the initial phase of the first meiotic division homologous chromosomes are arranged opposite to each other and couple, forming one or more areas of contact (chiasm) between individual unsisterly chromatids. Next, the pair of chromatids that formed chiasm exchanges the sections of DNA (crossing-over process). As a result of crossing-over recombinant chromosomes are formed consisting of sections originating from different parent lines. Upon the completion of ...
To facilitate this pairing, Dernburg has shown, each of the nematodes 12 chromosomes becomes attached by one end to patches on the nuclear membrane that envelops the chromosomes. The patches form a bridge between the chromosomes and the cytoskeleton outside the nucleus. The skeleton assists the random movement of these patches, each with a chromosome attached, around the nuclear membrane, until each chromosome encounters its homolog. Once a chromosome finds its mate and pairs up, the paired homologs remain attached to each other through recombination, separating only prior to segregation.. To many biologists, it seemed likely that synaptonemal complex formation would occur spontaneously between paired chromosomes, Dernburg said. But she and her colleagues have now shown that the cell actively prevents formation of the synaptonemal complex until it has checked and made sure the paired chromosomes are really homologs.. "The punch line of our paper is that it indicates there is a check point that ...
Meiosis Meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell. Meiosis is a process of reduction division in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell. Meiosis I- results in two diploid daughter cells, each with the same number of chromosomes as the original cell. Meiosis I- results in two diploid daughter cells, each with the same number of chromosomes as the original cell. Tetrad- structure formed by the pairing of homologous chromosomes Tetrad- structure formed by the pairing of homologous chromosomes Crossing-over- exchanging portions of chromatids while forming tetrads Crossing-over- exchanging portions of chromatids while forming tetrads
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 up on different ...
As this karyotype displays, a diploid human cell contains 22 pairs of homologous chromosomes and 2 sex chromosomes.. Section ... They define homologous chromosomes as: "chromosomes that pair during meiosis", which is the classical cytological definition. ... For example, Emmer wheat has the AABB chromosome sets (28 total chromosomes) from Triticum monococcum (AA, 14 chromosomes) and ... chromosomes." For example, the number of homologous sets of chromosomes in humans is 23 if one considers a "set" to be one pair ...
Number of chromosomes. 24 pairs. Relationships among apes. The numbers in this diagram are branch lengths, a measure of ... Duplications of small parts of chromosomes have been the major source of differences between human and chimp genetic material; ...
yeast artificial chromosome . yolk . Z lines . zoology . zygote . Contents: 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 ... electronegativity A measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most ... chromosome A threadlike strand of DNA in the cell nucleus that carries the genes in a linear order. clonal selection . cloning ... aneuploidy The presence of an abnormal number of chromosomes in a cell. antibiotic A type of antimicrobial drug used in the ...
... hybrids may be weak hybrids may be partially sterile chromosomes may pair poorly or not at all recovery of desired phenotypes ... hybrids are generally fertile with good chromosome pairing; gene segregation is approximately normal and gene transfer is ... chromosome doubling) bridging crosses (e.g., with members of the secondary gene pool). Gene pool centres refers to areas on the ...
Transvection appears to be dependent upon chromosome pairing. In some cases, if one allele is placed on a different chromosome ... The first observation of mitotic (i.e. non-meiotic) chromosome pairing was discovered via microscopy in 1908 by Nettie Stevens ... McKee BD (March 2004). "Homologous pairing and chromosome dynamics in meiosis and mitosis". Biochim. Biophys. Acta. 1677 (1-3 ... Other mechanisms include pairing-sensitive silencing and enhancer bypass of a chromatin insulator through pairing-mediated ...
Lutes, A. A., Neaves, W.B., Baumann, D. P., Wiegraebe, W., Baumann, P. (2010). Sister chromosome pairing maintains ... This diversity is maintained by combining sister chromatids instead of pairing homologous chromosomes, thus allowing a ... This is because the lizards start off with twice the amount of chromosomes as would be found in sexually reproducing ... Current studies suggest that the lizards may be able to distinguish between homologous chromosomes and sister chromatids. The ...
... containing both pairs of homologous chromosomes. There are 23 chromosome pairs. Thus, there are 46 chromosomes. Each chromosome ... Thus, it has only one of each pair of homologous chromosomes. In other words, it is haploid. However, each chromosome still has ... This is twice the number of chromosome pairs (2N). Oogonia are created in early embryonic life. All have turned into primary ... Each chromosome is split between the two ootids, leaving only one chromatid per chromosome. Thus, there are 23 chromatids in ...
Chromosome number 2n = 36, 48, or 96.[28] This subgenus is distributed throughout North, Central and South America, ... The first pair of true leaves is alternate. The stem is predominantly naked with waxen coating. Dominating is the monopodial ...
... is the pairing of two homologous chromosomes that occurs during meiosis. It allows matching-up of homologous pairs prior to ... Mitosis also has prophase, but does not ordinarily do pairing of two homologous chromosomes. When the non-sister chromatids ... McKee B (2004). "Homologous pairing and chromosome dynamics in meiosis and mitosis". Biochim Biophys Acta. 1677 (1-3): 165-80. ... Sex chromosomes also undergo synapsis; however, the synaptonemal protein complex that holds the homologous chromosomes together ...
Pairing of identical sister chromosomes, in comparison to the alternative of pairing homologous chromosomes, maintains ... Whereas homologous chromosomes pair and separate during meiosis I in sexual species, identical duplicate sister chromosomes, ... pair and separate during meiosis I in true parthenotes..... in comparison to the alternative of pairing homologous chromosomes ... 2010). "Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards". Nature. 464 (7286): 283-286. doi: ...
from base pair 8,120,590 to 8,126,032. In mice, HES7 is located on chromosome 11. HES7 has 62 known orthologues. The HES7 gene ... The gene that encodes the human HES7 protein is 5kb long and is found on chromosome 17, on the short arm at position 13.1. ... Each cycle of HES7 expression coincides with the formation of a pair of somites. The half life of the HES7 protein is thought ... HES7) or bHLHb37 is protein coding mammalian gene found on chromosome 17 in humans. HES7 is a member of the Hairy and Enhancer ...
Chromosomes are tiny packages which contain one DNA molecule and its associated proteins. Humans have 46 chromosomes (23 pairs ... By the time the zygote divides again, genetic recombination has created a new embryo with 23 pairs of chromosomes, half from ... There are about 3.2 billion nucleotide pairs on all the human chromosomes: this is the human genome. The order of the ... This exact pairing is called base pairing. When DNA is copied, the two strands of the old DNA are pulled apart by enzymes; then ...
Humans have 46 chromosomes (23 pairs). This number varies between species-for example, many primates have 24 pairs. Meiosis ... This exact pairing is called base pairing.[12]. When DNA is copied, the two strands of the old DNA are pulled apart by enzymes ... By the time the zygote divides again, genetic recombination has created a new embryo with 23 pairs of chromosomes, half from ... There are about 3.2 billion nucleotide pairs on all the human chromosomes: this is the human genome. The order of the ...
Chromosome pairing and the lampbrush diplotene stage of meiotic prophase". Chromosoma (Berlin). 29 (3): 305-16. doi:10.1007/ ... The chromosome number of C. micaceus is n=12. Coprinellus micaceus is an edible species, and cooking inactivates the enzymes ... The chromosomes are readily discernible with light microscopy, and all of the meiotic stages are well-defined. These features ... "Metabolite profiles of interacting mycelial fronts differ for pairings of the wood decay basidiomycete fungus, Stereum hirsutum ...
The bacterium contains a single chromosome and no known plasmids. The G+C content is 44.7%. The complete genome is accessible ... S. violacea contains 4,962,103 base pairs. It has 4,346 protein genes and 169 RNA genes. ...
"Homologous expressed genes in the human sex chromosome pairing region". Nature. 317 (6039): 739-41. doi:10.1038/317739a0. PMID ... Unusually for a gene present on the X chromosome, the CD99 gene does not undergo X inactivation, and it was the first such ... and the Y chromosome". Proc. Natl. Acad. Sci. U.S.A. 85 (15): 5605-9. doi:10.1073/pnas.85.15.5605. PMC 281808 . PMID 2456574. ... "Genetic evidence that a Y-linked gene in man is homologous to a gene on the X chromosome". Nature. 302 (5906): 346-9. doi: ...
On this chromosome are 2,715,461 base pairs. Of these base pairs there are 2573 coding sequences with only 2.1% of the genome ... Clostridium sticklandii has a genome that consists of one circular chromosome. ...
Both taxa also have 14 chromosome pairs. In 2006, the family's classification was redefined using molecular data. Here, Roupala ...
The addax has 29 pairs of chromosomes. All chromosomes are acrocentric except for the first pair of autosomes, which are ... The X chromosome is the largest of the acrocentric chromosomes, and the Y chromosome is medium-sized. The short and long arms ... of the pair of submetacentric autosomes correspond respectively to the 27th and 1st chromosomes in cattle and goats. In a study ... the banding patterns of chromosomes in addax were found to be similar to those in four other species of the subfamily ...
V. faba has a diploid (2n) chromosome number of 12 (six homologous pairs). Five pairs are acrocentric chromosomes and one pair ...
... is essential for homologous chromosome pairing in meiosis during spermatogenesis. Targeted inactivation of FKBP6 in mice ... 2003). "Essential role of Fkbp6 in male fertility and homologous chromosome pairing in meiosis". Science. 300 (5623): 1291-5. ...
In these mice, the prophase I stage of meiosis is defective due to the disruption of chromosome pairing. This meiotic failure ... "Mammalian MutS homologue 5 is required for chromosome pairing in meiosis". Nature Genetics. 21 (1): 123-7. doi:10.1038/5075. ... "Mammalian MutS homologue 5 is required for chromosome pairing in meiosis". Nature Genetics. 21 (1): 123-7. doi:10.1038/5075. ... but they accomplish this repair in a way that does not lead to crossovers between homologous chromosomes. The known mechanism ...
Genetically, there are 74 diploid chromosomes (36 pairs). The crab-eating fox is predominantly greyish-brown, with areas of red ... The adult female gives birth to one or two litters per year, and the breeding pair is monogamous. The pair ranges the plains ... It either hunts individually or lives in pairs; it eats crabs, lizards and different flying animals. It is easy to domesticate ... The crab-eating fox creates monogamic teams for hunting; groups of several monogamic pairs may form during the reproductive ...
In humans, we have 23 pairs of chromosomes. Another example is maize which is also a diploid with 10 pairs of chromosomes. ... However, with current technology, it is difficult to separate the two chromosomes within a pair and the assays produce the ... For diploid organisms such as humans and maize, each organism has two copies of a chromosome - one each from the two parents. ... A haplotype is the sequence of nucleotides in a chromosome. the haplotype phasing problem is focused on the nucleotides where ...
The mouse has approximately 2.7 billion base pairs and 20 chromosomes. They can also be manipulated in ways that are illegal ...
This article on a gene on human chromosome 2 is a stub. You can help Wikipedia by expanding it.. *v ... This gene is one of several homeobox HOXD genes located in a cluster on chromosome 2. Deletions that remove the entire HOXD ... Mammals possess four similar homeobox gene clusters, HOXA, HOXB, HOXC and HOXD, located on different chromosomes, consisting of ... "Clustering of two fragile sites and seven homeobox genes in human chromosome region 2q31→q32.1". Cytogenet. Cell Genet. 90 (1-2 ...
By "hybridization" is meant the pairing of complementary RNA and DNA strands to produce an RNA-DNA hybrid, or the partial ... The extra telocentric chromosome has two telomeres: one identical to that present on the full length chromosomes, and a new ... This chromosome undergoes breakage, followed by rearrangement or chromosome loss; these events can be detected by karyotype ... Moreover, since the telocentric chromosome is free to recombine with the full length chromosomes, and the telotrisomic stocks ...
"Chromosome 1 from your dad has to be paired with chromosome 1 from your mom, chromosome 2 from your dad with chromosome 2 from ... And because chromosomes come in pairs - 23 sets in humans - the chromosomes must be properly matched up before they can be ... chromosomes can pair up more easily if theyre able to recognize their partners and find them at a specific place. "Once ... and using it to form an intimate association that runs the entire length of each pair of chromosomes," Hawley explains. Some ...
Wettstein R. (1981) Unusual Mechanisms of Chromosome Pairing in Arthropoda. In: Schweiger H.G. (eds) International Cell Biology ... Both differentially condensed sex chromosomes present axial structures during meiotic prophase and pair their common ends, ... leading to a better knowledge of meiotic chromosome zones and to a complete analysis of pachytene chromosome complement of ... The application of these concepts to the study of the ultrastructure of mammalian sex chromosomes allowed the establishment of ...
Pairing of homologous chromosomes is an essential feature of meiosis, acting to promote high levels of recombination and to ... Homologous pairing and chromosome dynamics in meiosis and mitosis.. McKee BD1. ... which have allowed investigators to assay the pairing status of chromosomes directly. These approaches have permitted the ... and that the transition from mitotic to meiotic pairing in spermatogenesis is accompanied by a dramatic increase in pairing ...
Scientists are learning how tumor cells nutritional needs differ from those of normal cells. Will their work help launch the next genre of cancer therapies ...
... and the chromosomes can pair. In a wheat-rye hybrid carrying seven rye chromosomes (d), the rye heterochromatin does not ... the translocated chromosome behaves like the rest of the wheat chromosomes. In fact, initially this regular pairing led some ... Effective chromosome pairing requires chromatin remodeling at the onset of meiosis. Isabelle Colas, Peter Shaw, Pilar Prieto, ... Effective chromosome pairing requires chromatin remodeling at the onset of meiosis. Isabelle Colas, Peter Shaw, Pilar Prieto, ...
Segregation of genotypes through homoeologous chromosome pairing in the apogamous species Dryopteris nipponensiswas tested by ... Klekowski EJ, Hickok LG (1974) Non homologous chromosome pairing in the fern Ceratopteris. Amer J Bot 61:422-432Google Scholar ... Allozyme Apogamy Dryopteris Genotype segregation Homoeologous chromosome pairing This is a preview of subscription content, log ... Segregation of genotypes through homoeologous chromosome pairing in the apogamous species Dryopteris nipponensis was tested by ...
Two types of sites required for meiotic chromosome pairing in Caenorhabditis elegans.. K S McKim, K Peters and A M Rose ... Two types of sites required for meiotic chromosome pairing in Caenorhabditis elegans.. K S McKim, K Peters and A M Rose ... Two types of sites required for meiotic chromosome pairing in Caenorhabditis elegans.. K S McKim, K Peters and A M Rose ... Whereas the other half of chromosome I did not confer any ability for homologs to pair and recombine, deficiencies in this ...
... resulting in a total of 46 chromosomes. These chromosomes determine individual genetics traits as well as a persons gender.... ... Do homologous pairs of chromosomes carry the same genes?. A: Homologous pairs of chromosomes carry the same genes. Although the ... Twenty two of the chromosome pairs are similar in both males and females, and a pair of X and Y chromosomes determine the sex. ... Humans typically have 23 pairs of chromosomes, resulting in a total of 46 chromosomes. These chromosomes determine individual ...
... chromosome pairing include Examination of Mitotic and Meiotic Fission Yeast Nuclear Dynamics by Fluorescence Live-Cell ... Associated Chromosome Trap for Identifying Long-range DNA Interactions. ... Chromosome Pairing: The alignment of Chromosomes at homologous sequences. .article_summary_container button.expand{ display: ... Associated Chromosome Trap for Identifying Long-range DNA Interactions. Jianqun Ling1, Andrew R. Hoffman1 ...
Thus, telomere-led chromosome organization facilitates homologous pairing and also restricts irregular chromosome pairing ... The positions of chromosomes I, II and III, half-sized chromosomes (HC), and minichromosome Ch16 (mini) are indicated on the ... Telomere-led bouquet formation facilitates homologous chromosome pairing and restricts ectopic interaction in fission yeast ... Telomere-led bouquet formation facilitates homologous chromosome pairing and restricts ectopic interaction in fission yeast ...
... some evidence has been presented for somatic homologous associations or some other kind of relationship between chromosomes in ... Opposing views are held with respect to the time when and the mechanisms whereby homologous chromosomes find each other for ... The Initiation of Meiotic Chromosome Pairing: The Cytological View Genome. 1990 Dec;33(6):759-78. doi: 10.1139/g90-115. ... associations or some other kind of relationship between chromosomes in somatic cells as a preliminary to meiotic pairing. On ...
SUBSTITUTION OF RYE CHROMOSOME 5RL FOR CHROMOSOME 5B OF WHEAT AND ITS EFFECT ON CHROMOSOME PAIRING. L. M. Bielig and C. J. ... SUBSTITUTION OF RYE CHROMOSOME 5RL FOR CHROMOSOME 5B OF WHEAT AND ITS EFFECT ON CHROMOSOME PAIRING. L. M. Bielig and C. J. ... SUBSTITUTION OF RYE CHROMOSOME 5RL FOR CHROMOSOME 5B OF WHEAT AND ITS EFFECT ON CHROMOSOME PAIRING. L. M. Bielig and C. J. ... SUBSTITUTION OF RYE CHROMOSOME 5RL FOR CHROMOSOME 5B OF WHEAT AND ITS EFFECT ON CHROMOSOME PAIRING ...
Type 2 diabetes: Evidence for linkage on chromosome 20 in 716 Finnish affected sib pairs. Soumitra Ghosh, Richard M. Watanabe, ... Type 2 diabetes: Evidence for linkage on chromosome 20 in 716 Finnish affected sib pairs ... Type 2 diabetes: Evidence for linkage on chromosome 20 in 716 Finnish affected sib pairs ... Type 2 diabetes: Evidence for linkage on chromosome 20 in 716 Finnish affected sib pairs ...
Pairing and recombination of homologous chromosomes are essential for ensuring reductional segregation in meiosis. However, the ... Meiosis-Specific Noncoding RNA Mediates Robust Pairing of Homologous Chromosomes in Meiosis ... Meiosis-Specific Noncoding RNA Mediates Robust Pairing of Homologous Chromosomes in Meiosis ... Meiosis-Specific Noncoding RNA Mediates Robust Pairing of Homologous Chromosomes in Meiosis ...
The study uncovered how female clones double their chromosomes ... ... Hokkaido University researchers have developed a technique that allows them to track chromosomes during egg production in dojo ... Clonal reproduction assured by sister chromosome pairing in dojo loach, a teleost fish, Chromosome Research (2018). DOI: ... Moreover, their data suggested that sister chromosomes doubled from the same chromosome make pairs so that recombination ...
Chromosomes, Human, Pair 2: A specific pair of human chromosomes in group A (Chromosomes, Human, 1-3) of the human chromosome ...
Little is known about mechanisms that efficiently partition chromosomes to produce sperm. Using live imaging and tomographic ... Chromosome segregation during male meiosis is tailored to rapidly generate multitudes of sperm. ... reconstructions of spermatocyte meiotic spindles inCaenorhabditis elegans, we find the lagging X chromosome, a distinctive ... elegans males, is due to lack of chromosome pairing. The unpaired chromosome remains tethered to centrosomes by lengthening ...
HIM-8 binds to the X chromosome pairing center and mediates chromosome-specific meiotic synapsis.. Phillips CM1, Wong C, Bhalla ... HIM-8 Binds to the X Chromosome Pairing Center and Mediates Chromosome-Specific Meiotic Synapsis ... HIM-8 Binds to the X Chromosome Pairing Center and Mediates Chromosome-Specific Meiotic Synapsis ... HIM-8 Binds to the X Chromosome Pairing Center and Mediates Chromosome-Specific Meiotic Synapsis ...
A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification. ... Pair 3" by people in Harvard Catalyst Profiles by year, and whether "Chromosomes, Human, Pair 3" was a major or minor topic of ... "Chromosomes, Human, Pair 3" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH ( ... Below are the most recent publications written about "Chromosomes, Human, Pair 3" by people in Profiles. ...
... essentially reaching into the nucleus to bring chromosome pairs together in preparation for recombination and segregation. Read ... Chromosomes dance and pair up on the nuclear membrane. New findings by University of California, Berkeley, scientists including ... essentially reaching into the nucleus to bring chromosome pairs together in preparation for recombination and segregation. ...
This involves the pairing, or synapsis, of homologous chromosomes in which the chromosome from the mother pairs with the ... In humans, that means 46 chromosomes pair off into 23, but in the nematode, 12 chromosomes pair off into 6. ... the pairing of homologous chromosomes. In early meiosis, the chromosomes attach by their pairing centers to proteins on the ... until each chromosome encounters its homolog. Once a chromosome finds its mate and pairs up, the paired homologs remain ...
DNA Protein Analysis Of Human Chromosome 6, Counts 166,880,988 Base Pairs, Covers Global Diseases ...
Chromosome Mapping Chromosomes, Human, Pair 13 - genetics Chromosomes, Human, Pair 9 - genetics Genes, Recessive Genetic ... Chromosomes, Human, Pair 11 - genetics Chromosomes, Human, Pair 9 - genetics Female Finland Genetic markers Genetic ... Chromosome Mapping Chromosomes, Human, Pair 9 - genetics Comorbidity Genetic Linkage Genetic markers Genetic Predisposition to ... Chromosomes, Human, Pair 9 - genetics Cohort Studies DNA Mutational Analysis De Lange Syndrome - genetics Female Humans Male ...
... each chromosome only pairs with its identical, homologue, and not with related or homoelogous chromosomes). Chromosome pairing ... Chromosome pairing and recombination between H. chilense and wheat chromosomes were detected by genomic in situ hybridization. ... Chromosome pairing between Hordeum and wheat can be promoted in the absence of the Ph1 locus. ... However, in the absence of the Ph1 locus (ph1 mutant) the chance of pairing between related chromosomes is increased. In this ...
  • These chromosomes determine individual genetics traits as well as a person's gender. (reference.com)
  • As part of the International Multi-centre ADHD Genetics project we completed an affected sibling pair study of 142 narrowly defined Diagnostic and Statistical Manual of Mental Disorders, fourth edition combined type attention deficit hyperactivity disorder (ADHD) proband-sibling pairs. (soton.ac.uk)
  • JS Genetics announces the availability of XCAT-KS, its proprietary buccal swab test for the diagnosis of Klinefelter syndrome (KS) and other male sex chromosome aneuploidies. (news-medical.net)
  • What is chromosome 7, "Genetics Home Reference" of U.S. National Library of Medicine. (wikipedia.org)
  • Her studies have explored transvection in genetics, polycomb-group genes, chromatin pairing and remodeling, and the mechanisms of bridging promoter and enhancer elements within and between chromosomes. (wikipedia.org)
  • On the one hand, some evidence has been presented for somatic homologous associations or some other kind of relationship between chromosomes in somatic cells as a preliminary to meiotic pairing. (nih.gov)
  • Fluorescent signals indicate that the half of the chromosomes in the somatic cells of female clones are derived from type B (green signals). (phys.org)
  • According to the results published in Chromosome Research, the fluorescent signals indicated that somatic cells of the female clones have 25 chromosomes derived from type B, providing evidence that their ancestral origin arose when type A and B mated. (phys.org)
  • Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in nearly all somatic cells (cells other than egg and sperm cells). (wikipedia.org)
  • We identified a previously uncharacterized 125 aa region of Nup2 that is necessary and sufficient for its meiotic function, thus behaving as a meiotic autonomous region (MAR). Nup2-MAR forms distinct foci on spread meiotic chromosomes, with a subset overlapping with Ndj1 foci. (genetics.org)
  • To date, our best evidence for linkage is on chromosome 20 with potentially separable peaks located on both the long and short arms. (pnas.org)
  • In a sample from Botnia, Western Finland, a small number of selected pedigrees with the lowest quartile for mean 30-min insulin levels after oral glucose tolerance tests showed significant evidence for linkage to type 2 diabetes on chromosome 12q ( 3 ). (pnas.org)
  • More recently, evidence for linkage was obtained on chromosome 11q for both diabetes and body mass index (BMI) in 264 Pima Indian families ( 4 ). (pnas.org)
  • Several groups have reported modest evidence for linkage on chromosome 20 for type 2 diabetes ( 11 - 13 ). (pnas.org)
  • Linkage analysis of 25 extended families, in each of which at least one affected individual had panic disorder (PD), resulted in a LOD score of 4.18 at D9S271, on chromosome 9q31. (arctichealth.org)
  • Nonparametric analysis of chromosome 12 inheritance data collected with the MODY3-linked markers D12S349 and D12S86 provides evidence for linkage to NIDDM with P values of 0.04 and 0.006, respectively, in Caucasian sib pairs using similar analyses. (diabetesjournals.org)
  • No evidence for linkage of MODY1 and MODY3 markers to NIDDM in African-American sib pairs was observed. (diabetesjournals.org)
  • They conducted a linkage study of 1,176 families (931 from an Australian group and 245 from a UK group), each with at least two members - mainly affected sister pairs - with surgically diagnosed disease. (endometriosis.org)
  • genomewide P = .047) and another region of suggestive linkage on chromosome 20p13 (MLS = 2.09). (endometriosis.org)
  • Linkage of the gene for cystinosis to markers on the short arm of chromosome 17. (wikipedia.org)
  • The application of these concepts to the study of the ultrastructure of mammalian sex chromosomes allowed the establishment of a structural and behavioural pattern (especially through the extensive work performed by Solari). (springer.com)
  • Occasionally, a gamete carries extra chromosomes or not enough chromosomes. (reference.com)
  • The extra chromosomes are known as conditionally dispensable, or supernumerary, because they are dispensable for certain situations, but may confer a selective advantage under different environments. (wikipedia.org)
  • The term is sometimes also used to describe preservation of the precise order of genes on a chromosome passed down from a common ancestor, although many geneticists reject this use of the term. (wikipedia.org)
  • Chromomeric maps can be used to locate the exact position of genes on a chromosome. (wikipedia.org)
  • The depletion of PIP2 by type I PIP kinase (PPK-1) kinase RNA interference results in an altered chromosome structure and leads to various defects during meiotic progression. (mdpi.com)
  • B) Genomic localizations of the three FISH probes used to quantify homolog pairing. (nih.gov)
  • Zhongshuang 11 (B). (C and D) One ovary cell (2 n = 29) with nine C-subgenome chromosomes (red) and 20 A-subgenome chromosomes (blue) (C) from F 1 hybrid (D). No signals for the C. abyssinica genomic DNA probe (green) are detected. (genetics.org)