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: 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.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.Sex Chromosome Aberrations: Abnormal number or structure of the SEX CHROMOSOMES. Some sex chromosome aberrations are associated with SEX CHROMOSOME DISORDERS and SEX CHROMOSOME DISORDERS OF SEX DEVELOPMENT.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.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.Y Chromosome: The male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans and in some other male-heterogametic species in which the homologue of the X chromosome has been retained.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, 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.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).Chromosomes, Human, Pair 1: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) 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, 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.Chromosome Pairing: The alignment of CHROMOSOMES at homologous sequences.Chromosome Segregation: The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.Chromosomes, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.Sex Determination Processes: The mechanisms by which the SEX of an individual's GONADS are fixed.In Situ Hybridization, Fluorescence: A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.Karyotyping: Mapping of the KARYOTYPE of a cell.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 21: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 17: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.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.Chromosome Deletion: Actual loss of portion of a chromosome.Chromosomes, Human, Pair 6: A specific pair GROUP C CHROMSOMES of the human chromosome classification.Chromosomes, Artificial, Bacterial: DNA constructs that are composed of, at least, a REPLICATION ORIGIN, for successful replication, propagation to and maintenance as an extra chromosome in bacteria. In addition, they can carry large amounts (about 200 kilobases) of other sequence for a variety of bioengineering purposes.Chromosome 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 9: A specific pair of GROUP C CHROMSOMES of the human chromosome classification.Silene: A plant genus of the family CARYOPHYLLACEAE. The common name of campion is also used with LYCHNIS. The common name of 'pink' can be confused with other plants.Chromosomes, Fungal: Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.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.Chromosome Disorders: Clinical conditions caused by an abnormal chromosome constitution in which there is extra or missing chromosome material (either a whole chromosome or a chromosome segment). (from Thompson et al., Genetics in Medicine, 5th ed, p429)Chromosomes, Human, 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.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).Genes, Y-Linked: Genes that are located on the Y CHROMOSOME.Chromosomes, Human, Pair 18: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.Chromosomes, Insect: Structures within the CELL NUCLEUS of insect cells containing DNA.Chromosomes, Human, Pair 2: A specific pair of human chromosomes in group A (CHROMOSOMES, HUMAN, 1-3) of the human chromosome classification.Genes, X-Linked: Genes that are located on the X CHROMOSOME.Chromosomes, Human, Pair 16: A specific pair of GROUP E CHROMOSOMES of the human chromosome classification.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.Chromosomes, Human, Pair 22: A specific pair of GROUP G CHROMOSOMES of the human chromosome classification.Genetic Linkage: The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.Chromosomes, Human, 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, Pair 19: A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.Chromosomes, Human, Pair 8: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Platypus: A small aquatic oviparous mammal of the order Monotremata found in Australia and Tasmania.Chromosomes, Human, Pair 5: One of the two pairs of human chromosomes in the group B class (CHROMOSOMES, HUMAN, 4-5).Chromosomes, Human, Pair 12: A specific pair of GROUP C CHROMOSOMES of the human chromosome classification.Sex Characteristics: Those characteristics that distinguish one SEX from the other. The primary sex characteristics are the OVARIES and TESTES and their related hormones. Secondary sex characteristics are those which are masculine or feminine but not directly related to reproduction.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.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)Chromosomes, Human, Pair 20: A specific pair of GROUP F CHROMOSOMES of the human chromosome classification.Chromosome Structures: Structures which are contained in or part of CHROMOSOMES.Chromosomes, Human, Pair 15: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.Klinefelter Syndrome: A form of male HYPOGONADISM, characterized by the presence of an extra X CHROMOSOME, small TESTES, seminiferous tubule dysgenesis, elevated levels of GONADOTROPINS, low serum TESTOSTERONE, underdeveloped secondary sex characteristics, and male infertility (INFERTILITY, MALE). Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several karyotype variants include 48,XXYY; 48,XXXY; 49,XXXXY, and mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).Genetic Markers: A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.Chromosomes, Human, Pair 14: A specific pair of GROUP D CHROMOSOMES of the human chromosome classification.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.XYY Karyotype: Abnormal genetic constitution in males characterized by an extra Y chromosome.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.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Chromosomes, Human, 16-18: The short, submetacentric human chromosomes, called group E in the human chromosome classification. This group consists of chromosome pairs 16, 17, and 18.Chromosomes, Human, 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.Genes, sry: The primary testis-determining gene in mammalians, located on the Y CHROMOSOME. It codes for a high mobility group box transcription factor (TRANSCRIPTION FACTORS) which initiates the development of the TESTES from the embryonic GONADS.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.Pachytene Stage: The stage in the first meiotic prophase, following ZYGOTENE STAGE, when CROSSING OVER between homologous CHROMOSOMES begins.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.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.Chromosome Breakage: A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.Dosage Compensation, Genetic: Genetic mechanisms that allow GENES to be expressed at a similar level irrespective of their GENE DOSAGE. This term is usually used in discussing genes that lie on the SEX CHROMOSOMES. Because the sex chromosomes are only partially homologous, there is a different copy number, i.e., dosage, of these genes in males vs. females. In DROSOPHILA, dosage compensation is accomplished by hypertranscription of genes located on the X CHROMOSOME. In mammals, dosage compensation of X chromosome genes is accomplished by random X CHROMOSOME INACTIVATION of one of the two X chromosomes in the female.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.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.Carica: A plant genus of the family Caricaceae, order Violales, subclass Dilleniidae, class Magnoliopsida. It is the source of edible fruit and PAPAIN.Ring Chromosomes: Aberrant chromosomes with no ends, i.e., circular.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.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.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.Chromosome Positioning: The mechanisms of eukaryotic CELLS that place or keep the CHROMOSOMES in a particular SUBNUCLEAR SPACE.Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.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.Sex Differentiation: The process in developing sex- or gender-specific tissue, organ, or function after SEX DETERMINATION PROCESSES have set the sex of the GONADS. Major areas of sex differentiation occur in the reproductive tract (GENITALIA) and the brain.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.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).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.Trisomy: The possession of a third chromosome of any one type in an otherwise diploid cell.Sex Determination Analysis: Validation of the SEX of an individual by inspection of the GONADS and/or by genetic tests.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Turner Syndrome: A syndrome of defective gonadal development in phenotypic females associated with the karyotype 45,X (or 45,XO). Patients generally are of short stature with undifferentiated GONADS (streak gonads), SEXUAL INFANTILISM, HYPOGONADISM, webbing of the neck, cubitus valgus, elevated GONADOTROPINS, decreased ESTRADIOL level in blood, and CONGENITAL HEART DEFECTS. NOONAN SYNDROME (also called Pseudo-Turner Syndrome and Male Turner Syndrome) resembles this disorder; however, it occurs in males and females with a normal karyotype and is inherited as an autosomal dominant.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)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.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.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.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.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.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.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.Spermatogenesis: The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA.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.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Sex Chromosome Disorders of Sex Development: Congenital conditions of atypical sexual development associated with abnormal sex chromosome constitutions including MONOSOMY; TRISOMY; and MOSAICISM.Disorders of Sex Development: In gonochoristic organisms, congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. Effects from exposure to abnormal levels of GONADAL HORMONES in the maternal environment, or disruption of the function of those hormones by ENDOCRINE DISRUPTORS are included.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Diploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.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."Chromosome Duplication: An aberration in which an extra chromosome or a chromosomal segment is made.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.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Dromaiidae: A family of flightless, running BIRDS, in the order Casuariiformes. The emu is the only surviving member of the family. They naturally inhabit forests, open plains, and grasslands in Australia.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.Infertility, Male: The inability of the male to effect FERTILIZATION of an OVUM after a specified period of unprotected intercourse. Male sterility is permanent infertility.Marsupialia: An infraclass of MAMMALS, also called Metatheria, where the young are born at an early stage of development and continue to develop in a pouch (marsupium). In contrast to Eutheria (placentals), marsupials have an incomplete PLACENTA.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).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)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.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.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.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.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.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).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.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.Genetic Variation: Genotypic differences observed among individuals in a population.Sex: The totality of characteristics of reproductive structure, functions, PHENOTYPE, and GENOTYPE, differentiating the MALE from the FEMALE organism.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.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.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.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.Monosomy: The condition in which one chromosome of a pair is missing. In a normally diploid cell it is represented symbolically as 2N-1.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.Testis: The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.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.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.Smegmamorpha: Group of fish under the superorder Acanthopterygii, separate from the PERCIFORMES, which includes swamp eels, mullets, sticklebacks, seahorses, spiny eels, rainbowfishes, and KILLIFISHES. The name is derived from the six taxa which comprise the group. (From http://www.nanfa.org/articles/Elassoma/elassoma.htm, 8/4/2000)Heterozygote: An individual having different alleles at one or more loci regarding a specific character.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.Sex Ratio: The number of males per 100 females.Quantitative Trait Loci: Genetic loci associated with a QUANTITATIVE TRAIT.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.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.Muntjacs: A genus, Muntiacus, of the deer family (Cervidae) comprising six species living in China, Tibet, Nepal, India, the Malay Peninsula, and neighboring island countries. They are usually found in forests and areas of dense vegetation, usually not far from water. They emit a deep barklike sound which gives them the name "barking deer." If they sense a predator they will "bark" for an hour or more. They are hunted for their meat and skins; they thrive in captivity and are found in many zoos. The Indian muntjac is believed to have the lowest chromosome number in mammals and cell lines derived from them figure widely in chromosome and DNA studies. (From Walker's Mammals of the World, 5th ed., p1366)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.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.Genome: The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.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.Sex-Determining Region Y Protein: A transcription factor that plays an essential role in the development of the TESTES. It is encoded by a gene on the Y chromosome and contains a specific HMG-BOX DOMAIN that is found within members of the SOX family of transcription factors.Genes, Insect: The functional hereditary units of INSECTS.Spermatids: Male germ cells derived from the haploid secondary SPERMATOCYTES. Without further division, spermatids undergo structural changes and give rise to SPERMATOZOA.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)Diptera: An order of the class Insecta. Wings, when present, number two and distinguish Diptera from other so-called flies, while the halteres, or reduced hindwings, separate Diptera from other insects with one pair of wings. The order includes the families Calliphoridae, Oestridae, Phoridae, SARCOPHAGIDAE, Scatophagidae, Sciaridae, SIMULIIDAE, Tabanidae, Therevidae, Trypetidae, CERATOPOGONIDAE; CHIRONOMIDAE; CULICIDAE; DROSOPHILIDAE; GLOSSINIDAE; MUSCIDAE; TEPHRITIDAE; and PSYCHODIDAE. The larval form of Diptera species are called maggots (see LARVA).Oligospermia: A condition of suboptimal concentration of SPERMATOZOA in the ejaculated SEMEN to ensure successful FERTILIZATION of an OVUM. In humans, oligospermia is defined as a sperm count below 20 million per milliliter semen.Haploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented once. Symbol: N.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.Polyploidy: The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.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.Characiformes: An order of fresh water fish with 18 families and over 1600 species. The order includes CHARACINS, hatchetfish, piranhas, and TETRAS.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.Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.DNA-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.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.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 Fragility: Susceptibility of chromosomes to breakage leading to translocation; CHROMOSOME INVERSION; SEQUENCE DELETION; or other CHROMOSOME BREAKAGE related aberrations.Hybridization, Genetic: The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid.Gonadal Dysgenesis, Mixed: A type of defective gonadal development in patients with a wide spectrum of chromosomal mosaic variants. Their karyotypes are of partial sex chromosome monosomy resulting from an absence or an abnormal second sex chromosome (X or Y). Karyotypes include 45,X/46,XX; 45,X/46,XX/47,XXX; 46,XXp-; 45,X/46,XY; 45,X/47,XYY; 46,XYpi; etc. The spectrum of phenotypes may range from phenotypic female to phenotypic male including variations in gonads and internal and external genitalia, depending on the ratio in each gonad of 45,X primordial germ cells to those with normal 46,XX or 46,XY constitution.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.Physical Chromosome Mapping: Mapping of the linear order of genes on a chromosome with units indicating their distances by using methods other than genetic recombination. These methods include nucleotide sequencing, overlapping deletions in polytene chromosomes, and electron micrography of heteroduplex DNA. (From King & Stansfield, A Dictionary of Genetics, 5th ed)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.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.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.Gene Rearrangement: The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.Gene Duplication: Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.Mammals: Warm-blooded vertebrate animals belonging to the class Mammalia, including all that possess hair and suckle their young.Sex Preselection: Methods for controlling genetic SEX of offspring.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)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.Genes, Plant: The functional hereditary units of PLANTS.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.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.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)Echidna: An oviparous burrowing mammal of the order Monotremata native to Australia, Tasmania, and New Guinea. It has hair mingled with spines on the upper part of the body and is adapted for feeding on ants.Abnormalities, MultipleUniparental Disomy: The presence in a cell of two paired chromosomes from the same parent, with no chromosome of that pair from the other parent. This chromosome composition stems from non-disjunction (NONDISJUNCTION, GENETIC) events during MEIOSIS. The disomy may be composed of both homologous chromosomes from one parent (heterodisomy) or a duplicate of one chromosome (isodisomy).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)Ploidies: The degree of replication of the chromosome set in the karyotype.Synaptonemal Complex: The three-part structure of ribbon-like proteinaceous material that serves to align and join the paired homologous CHROMOSOMES. It is formed during the ZYGOTENE STAGE of the first meiotic division. It is a prerequisite for CROSSING OVER.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.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.Retroelements: Elements that are transcribed into RNA, reverse-transcribed into DNA and then inserted into a new site in the genome. Long terminal repeats (LTRs) similar to those from retroviruses are contained in retrotransposons and retrovirus-like elements. Retroposons, such as LONG INTERSPERSED NUCLEOTIDE ELEMENTS and SHORT INTERSPERSED NUCLEOTIDE ELEMENTS do not contain LTRs.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.Polytene Chromosomes: Extra large CHROMOSOMES, each consisting of many identical copies of a chromosome lying next to each other in parallel.DNA Replication: The process by which a DNA molecule is duplicated.Cosmids: Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.Genetic Predisposition to Disease: A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.
A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two ... sex chromosomes. In most cases, males with an X-linked form of this condition experience more severe dental abnormalities than ... M, Kida (2002). "Autosomal-dominant hypoplastic form of amelogenesis imperfecta caused by an enamelin gene mutation at the exon ... Mutations in the ENAM gene are the most frequent known cause and are most commonly inherited in an autosomal dominant pattern. ...
Deadpan is an autosomal gene which inhibits sex-lethal, while sisterless is carried on the X chromosome and inhibits the action ... Sex determination[edit]. Drosophila flies have both X and Y chromosomes, as well as autosomes. Unlike humans, the Y chromosome ... It is caused by mutations in the gene WRN that encodes a protein with essential roles in repair of DNA damage. Mutations in the ... He discovered that the gene was located on the X chromosome with this information. This led to the discovery of sex-linked ...
The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes (autosomes) and ... This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of ... Main article: Sex linkage. In humans and other mammal species, sex is determined by two sex chromosomes called the X chromosome ... Genetic traits on the X and Y chromosomes are called sex-linked, because they are linked to sex chromosomes, not because they ...
X-linked genes are found on the sex X chromosome. X-linked genes just like autosomal genes have both dominant and recessive ... FISH uses fluorescent probes to bind to specific sequences of the chromosomes that will cause the chromosomes to fluoresce a ... Autosomal traits are associated with a single gene on an autosome (non-sex chromosome)-they are called "dominant" because a ... and are called the homogametic sex. Males have two distinct sex chromosomes (XY), and are called the heterogametic sex. Sex ...
These are characters only expressed in one sex. They may be caused by genes on either autosomal or sex chromosomes. Examples: ... the first sex-linked gene discovered. Fur color in domestic cats: the gene that causes orange pigment is on the X chromosome; ... sex chromosome) of the individual. In autosomal chromosomes both sexes have the same probability of existing (see Fisher's ... while the male is the heterogametic sex, with one X and one Y chromosome (XY). Genes on the X or Y chromosome are called sex- ...
"Campomelic dysplasia and autosomal sex reversal caused by mutations in an SRY-related gene." Nature 372.6506 (1994): 525-529. " ... Aneuploidy (abnormal number of chromosomes) Autosomal dominant Autosomal recessive Homologous chromosome Pseudoautosomal region ... TDF functions by activating the SOX9 gene on chromosome 17, so mutations of the SOX9 gene can cause humans with a Y chromosome ... Unlike single gene disorders, diseases caused by aneuploidy are the result of improper gene dosage, not nonfunctional gene ...
... one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is ... In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are ... Types I and III are inherited in an autosomal recessive pattern, which means two copies of the gene in each cell are altered. ... A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, ...
... if it possesses two Y chromosomes (YY) or if the Y chromosome possesses the female suppression and male promoting genes. Silene ... can develop uni-sexual reproductive structures because of the loss and gain of sex-determining genes. Mutations can cause ... As these chromosomes diverge from their autosomal ancestor and from each other as a homologous pair, they have the potential to ... This is made possible through heteromorphic sex chromosomes expressed as XY. Silene recently evolved sex chromosomes 5-10 ...
The primary cause of this difference in gene expression was thought to be SNPs in gene regulatory regions of DNA. Another study ... Chromosome abnormalities are detected in 1 of 160 live human births. Apart from sex chromosome disorders, most cases of ... the most common extra autosomal chromosomes among live births are 21, 18 and 13. Nucleotide diversity is the average proportion ... The main cause is genetic drift, this is the effect of random changes in the gene pool. In humans, founder effect and past ...
... which have to do with genetic differences on the sex chromosomes (see sex-determination system). Sex-limited genes are also ... In other words, sex-limited genes cause the two sexes to show different traits or phenotypes, despite having the same genotype ... where the factors that modify the gene are located next to the gene on the chromosome. (This is in contrast to trans-dominance ... This term is restricted to autosomal traits, and should not be confused with sex-linked characteristics, ...
The most common isochromosome is the X sex chromosome. Acrocentric autosomal chromosomes 13, 14, 15, 21, and 22 are also common ... The neoplasia created from i(17q) is caused by a decrease and increase in gene dosage from the monosomy of the p arm and ... Turner syndrome is a condition in females in which there is partial or complete loss of one X chromosome. This causes symptoms ... Since the p-arm of the X chromosome contains genes that are necessary for normal sexual development, Turner's syndrome patients ...
... "sex chromosomes" (the X or Y chromosomes) versus whether they are located on "autosomal" chromosomes (chromosomes other than ... The specific gene on the X chromosome is referred to as MTM-1. In theory, some cases of CNM may be caused by an abnormality on ... or autosomal. Females have two X-chromosomes, while males only have a single X chromosome, and a genetic abnormality located on ... the X chromosome is much more likely to cause clinical disease in a male (who lacks the possibility of having the normal gene ...
It is due to a mutation in the gene TTC7A on short arm of chromosome 2 (2p16). It is inherited as an autosomal recessive gene ... The most common cause of non-duodenal intestinal atresia is a vascular accident in utero that leads to decreased intestinal ... An amniocentesis is recommended because it can determine not only the sex of the baby, but whether or not there is a problem ... Some fetuses with bowel obstruction have abnormal chromosomes. ... with the chromosomes. Fetal and neonatal intestinal atresia are ...
Weng S, Stoner SA, Zhang DE (2016) Sex chromosome loss and the pseudoautosomal region genes in hematological malignancies. ... are inherited just like any autosomal genes. PAR1 comprises 2.6 Mbp of the short-arm tips of both X and Y chromosomes in humans ... and consequently cause male infertility. The SHOX gene in the PAR1 region is the gene most commonly associated with and well ... all pseudoautosomal genes escape X-inactivation and are therefore candidates for having gene dosage effects in sex chromosome ...
In higher eukaryotes with dimorphic sex chromosomes, such as humans and fruit flies, males have one X chromosome, whereas ... the scientists found that autosomal genes are more likely to undergo nonsense-mediated decay than X-linked genes. This is ... This disorder is caused by mutations in the fibrillin 1 (FBN1) gene and is resulted from a dominant negative interaction ... For instance, the blood disorder Beta thalassemia is inherited and caused by mutations within the upstream of the β-globin gene ...
This could cause the heterogametic sex chromosome in the hybrid to be inviable or sterile, but homogametic sex chromosome will ... It is now known that Drosophila has 6 chromosomes-an X/Y pair and four autosomal chromosomes. The genome comprises about 139.5 ... compared with the degree of misregulation of non-sex biased genes studied. The sex-lethal gene is often abnormally expressed in ... Recent studies have shown that a critical gene for gender determination in Drosophila known as the sex-lethal gene is highly ...
25,000 total genes in the human genome. Each person usually has one pair of sex chromosomes in each cell. Females have two X ... However, the other genes of the X chromosome cause feminization as well. X-linked endothelial corneal dystrophy is an extremely ... 2005 and Ohno 1967 that the X chromosome is at least partially derived from the autosomal (non-sex-related) genome of other ... The X chromosome carries hundreds of genes but few, if any, of these have anything to do directly with sex determination. Early ...
1995). "Autosomal sex reversal and campomelic dysplasia are caused by mutations in and around the SRY-related gene SOX9". Cell ... "SRY gene transferred to the long arm of the X chromosome in a Y-positive XX true hermaphrodite". Am. J. Med. Genet. 90 (1): 25- ... a fetus with both X and Y chromosomes can develop female gonads; the same is true if Dax1 is not present. The related phenomena ... 1995). "Campomelic dysplasia and autosomal sex reversal caused by mutations in an SRY-related gene". Nature. 372 (6506): 525-30 ...
From current data, approximately 45% of the known cases are caused by mutations in the AMH gene, being a mutation on chromosome ... PMDS is inherited in an autosomal recessive manner.[5] The male individuals inherit mutated copies of the X-chromosomes from ... The role of the AMH gene in reproductive development, is the production of a protein that contributes to male sex ... Mutation in AMH gene (PMDS Type 1) or AMHR2 gene (PMDS Type 2) are the primary causes of PMDS.[5] AMH, or sometimes referred to ...
... has 8 pairs of chromosomes (2n = 16)-7 autosomal pairs and 1 sex pair. The female schistosome is ... Clinical symptoms are caused by the eggs. As the leading cause of schistosomiasis in the world, it is the most prevalent ... "Killer parasites' genes decoded". BBC News. July 16, 2009. Retrieved 2009-07-16. Anna V. Protasio; Isheng J. Tsai; Anne Babbage ... April 2000). "Construction and characterization of a Schistosoma mansoni bacterial artificial chromosome library". Genomics. 65 ...
This means that there is an abnormal gene on one of the autosomal (non-sex) chromosomes from either parent. Because the gene is ... During reproduction, each parent contributes 23 chromosomes; 22 autosomal chromosomes and one sex chromosome. As stated above, ... The clefting often causes hypernasal speech and velopharyngeal incompetence. Because of this, compensatory articulation ... A normal human karyotype includes 22 pairs of autosomal or non-sex chromosomes and one pair of sex chromosomes, constituting a ...
... but there are only 22 pairs of homologous autosomal chromosomes. The additional 23rd pair is the sex chromosomes, X and Y. If ... SDSA recombination does not cause crossing-over. In the process of crossing-over, genes are exchanged by the breaking and union ... Homologous chromosomes are chromosomes which contain the same genes in the same order along their chromosomal arms. There are ... It reduces the chromosome number in a germ cell by half by first separating the homologous chromosomes in meiosis I and then ...
2. Involved chromosomes. *Autosomal - loci are not situated on a sex chromosome ... An example pedigree chart of a sex-linked disorder (the gene is on the X chromosome) ... Trofim Lysenko however caused a backlash of what is now called Lysenkoism in the Soviet Union when he emphasised Lamarckian ... Gonosomal - loci are situated on a sex chromosome *X-chromosomal - loci are situated on the X-chromosome (the more common case) ...
In mammals, one of the autosome pair, now Y, mutated its SOX3 gene into the SRY gene, causing that chromosome to designate sex ... sex chromosomes share no homologues with eutherian sex chromosomes. Instead, homologues with eutherian sex chromosomes lie on ... Huang, Bing; Wang, S; Ning, Y; Lamb, A. N.; Bartley, J (7 December 1999). "Autosomal XX sex reversal caused by duplication of ... elegans is male with one sex chromosome (X0); with a pair of chromosomes (XX) it is a hermaphrodite. Its main sex gene is XOL, ...
... sex chromosomes do not exhibit any type of chromosome-wide dosage compensation, and instead seem to dosage compensate on a gene ... but that the sex chromosomes are derived from autosomal chromosomes of the common ancestor. These autosomes are thought to have ... It appears possible that either condition could cause embryonic death, or that both chromosomes could be responsible for sex ... Males are the homogametic sex (ZZ), while females are the heterogametic sex (ZW). The Z chromosome is larger and has more genes ...
The XY sex-determination system is the sex-determination system found in humans, most other mammals, some insects (Drosophila), some snakes, and some plants (Ginkgo). In this system, the sex of an individual is determined by a pair of sex chromosomes. Females typically have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Males typically have two different kinds of sex chromosomes (XY), and are called the heterogametic sex. In humans, the presence of the Y chromosome is responsible for triggering male development; in the absence of the Y chromosome, the fetus will undergo female development. ...
An allosome (also referred to as a sex chromosome, heterotypical chromosome, heterochromosome, or idiochromosome) is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction. Autosomes differ from allosomes because autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell, whereas members of an allosome pair may differ from one another and thereby determine sex. In humans, each cell nucleus contains 23 pairs of chromosomes, a total of 46 chromosomes. The first ...
Most mammals are viviparous, giving birth to live young. However, the five species of monotreme, the platypuses and the echidnas, lay eggs. The monotremes have a sex determination system different from that of most other mammals. In particular, the sex chromosomes of a platypus are more like those of a chicken than those of a therian mammal. The mammary glands of mammals are specialized to produce milk, a liquid used by newborns as their primary source of nutrition. The monotremes branched early from other mammals and do not have the nipples seen in most mammals, but they do have mammary glands. The young lick the milk from a mammary patch on the mother's belly. Viviparous mammals are in the subclass Theria; those living today are in the Marsupialia and Placentalia infraclasses. A marsupial has a short gestation period, typically shorter than its estrous cycle, and gives birth to an underdeveloped ...
By one estimate, the human Y chromosome has lost 1,393 of its 1,438 original genes over the course of its existence, and linear extrapolation of this 1,393-gene loss over 300 million years gives a rate of genetic loss of 4.6 genes per million years.[21] Continued loss of genes at the rate of 4.6 genes per million years would result in a Y chromosome with no functional genes - that is the Y chromosome would lose complete function - within the next 10 million years, or half that time with the current age estimate of 160 million years.[16][22] Comparative genomic analysis reveals that many mammalian species are experiencing a similar loss of function in their heterozygous sex chromosome. Degeneration may simply be the fate of all non-recombining sex ...
Treatments exist for the various symptoms associated with XXXY syndrome. Testosterone therapy, which is giving affected individuals doses of testosterone on a regular basis, has been shown to reduce aggressive behavior in these patients.[3] But, this therapy has also been associated with negative side effects: worsening of behavior, and osteoporosis.[3] Not all individuals are applicable for testosterone therapy, as the best results are often achieved when dosage begins at the initiation of puberty, and these individuals are often diagnosed at a later age, or not at all.[3] Testosterone therapy has been shown to have no positive effect on fertility.[2] Consideration of the psychological phenotype of individuals with XXXY should be taken into account when treating these patients, because these traits affect compliance with treatments.[3] When caught early, Taurodontism can be treated with a root canal and is often successful.[2] Appropriate planning to avoid Taurodontism is possible, but this ...
A single X chromosome can have either a black allele of the coloration gene or an orange version, but not both. However, a female cat has two X chromosomes, so it can have both versions, black on one chromosome and orange on the other, making the cat a calico. A male cat usually has one X chromosome and one Y chromosome. A Y chromosome does not have a color gene, so the cat can have either an orange or a black gene, but not both. Calico cats are often used as an example in biology classes when discussing sex chromosomes. During the early stages of development, when the cat is still an embryo, in each cell one of the X chromosomes (either the black one or the orange one) deactivates. It is called X-inactivation. All cells that were copied from a cell with a deactivated X ...
The Y chromosome is ane o twa sex chromosomes (allosomes) in mammals, includin humans, an mony ither ainimals. The ither is the X chromosome. Y is the sex-determinin chromosome in mony species, syne it is the presence or absence o Y that determines the male or female sex o offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which causes testis development. ...
Hybridization between gray wolf and coyote has long been recognized both in the wild and in captivity. In an evolutionary biology research conducted by a team of researchers in the Uppsala University, analysis of control region haplotypes of the mitochondrial DNA and sex chromosomes from Mexican wolves, a critically endangered subspecies of the grey wolf once nearly driven to extinction in the wild, confirmed the presence of coyote markers in some of the wolves.[17] The study suggests that at some point in time, female coyotes managed to mate with some of the male wolves of the remnant wild Mexican wolf populations. Analysis on the haplotype of some coyotes from Texas also detected the presence of male wolf introgression such as Y chromosomes from the grey wolves in the southern coyotes. In one cryptology investigation on a corpse of what was initially labelled as a chupacabra, examinations conducted by the ...
Intersex variations occur (though rarely) in species which use sexual reproduction. Intersex people are born with sex characteristics that lie between those of typical males and typical females.[1][2] Hermaphrodite is a term that gets confused with intersexual, and while all hermaphrodites are intersexual, not all intersexual people are hermaphrodites. [3] The clinical term 'disorders of sex development' (DSD) is very controversial.[4][5][6] An intersex individual's genitalia may be atypical in some way. It can be difficult to determine if an intersex baby is genetically male or female (with XY chromosomes or XX ...
An allele is a form of a gene at a particular position (locus) on a chromosome.[1]15 It is the bit of coding DNA at that place.[2]p6 Typical plants and animals have two sets of chromosomes, one set inherited from each parent.[1]123 These organisms are called diploid. Since such organisms have two sets of chromosomes, they have (except on the sex chromosomes) two alleles at each gene locus.[2]p6 If the two alleles are identical, the individual is called a homozygote and is said to be homozygous. If instead the two alleles are different, the individual is a heterozygote and is heterozygous.[1]205 ...
The DNA content of a cell is duplicated at the start of the cell reproduction process. Prior to DNA replication, the DNA content of a cell can be represented as the amount Z (the cell has Z chromosomes). After the DNA replication process, the amount of DNA in the cell is 2Z (multiplication: 2 x Z = 2Z). During Binary fission and mitosis the duplicated DNA content of the reproducing parental cell is separated into two equal halves that are destined to end up in the two daughter cells. The final part of the cell reproduction process is cell division, when daughter cells physically split apart from a parental cell. During meiosis, there are two cell division steps that together produce the four daughter cells. Immediately after DNA replication a human cell will have 46 "double chromosomes". In each double chromosome there are two copies of that chromosome's DNA molecule. During mitosis the double ...
There has always been some type of differences between siblings, especially different sex siblings. Often, different sex sibling may consider things to be unfair because his/her brother/sister is allowed to do certain things just because of his or her gender, while he or she gets to do something less amusing or just plain different. McHale and her colleague conducted a longitudinal study using middle age children and observed the way in which the parents contributed to stereotypical attitudes in their kids.[38] In their study the experimenters analysed two different types of families, one with the same sex siblings, and the other with different sex siblings, as well as the children's birth order.[39] The experiment was conducted over phone interviews, in which the experimenters would ask the children about the activities they performed throughout their day outside of ...
There has always been some type of differences between siblings, especially different sex siblings. Often, different sex sibling may consider things to be unfair because his/her brother/sister is allowed to do certain things just because of his or her gender, while he or she gets to do something less amusing or just plain different. McHale and her colleague conducted a longitudinal study using middle age children and observed the way in which the parents contributed to stereotypical attitudes in their kids.[38] In their study the experimenters analysed two different types of families, one with the same sex siblings, and the other with different sex siblings, as well as the children's birth order.[39] The experiment was conducted over phone interviews, in which the experimenters would ask the children about the activities they performed throughout their day outside of ...
... et al.Increased number of sex chromosomes affects height in a nonlinear fashion. a study of 305 patients with sex chromosome ... Mutations of the mitochondrial ND1 gene as a cause of MELAS. J Med Genet. 2004;41:784-9 ... located in the pseudo-autosomal region 1 (PAR1) in the terminal region of Xp [14]. As shown, the over-expression of a growth- ... Heterogeneous gene expression from the inactive X chromosome: An X-linked gene that escapes X inactivation in some human cell ...
The COL4A5 gene is located on the X chromosome. The COL4A3 and the COL4A4 genes are located on chromosome 2. Chromosomes, which ... Autosomal dominant Alport syndrome is caused by mutations in one copy of either the COL4A3 gene or the COL4A4 gene. Dominant ... Autosomes are the non-sex chromosomes that carry most of our genes. There are 22 autosomes and cells have two copies of each ... X-linked Alport syndrome is caused by mutations in the COL4A5 gene, which resides on the X chromosome. X-linked disorders cause ...
The term autosomal means that the mutated gene is not located on either of the chromosomes that determine a persons sex; in ... a segment of chromosome on which a certain gene is located) have been found to cause Usher syndrome, and nine genes have been ... Mutated genes may cause cells to act differently than expected.. Usher syndrome is inherited as an autosomal recessive trait. ... People with a mutation in a gene that can cause an autosomal recessive disorder are called carriers, because they carry the ...
Study PA20293 gene transcription and DNA flashcards from Olivia Watkins ... The gene causing the disease is not present on the sex chromosome. Ie not X linked (XX, XY). Autosomal dominant and autosomal ... Abnormal crossovers between chromosomes during cell division. They cause a split in a gene, and joining with another part of a ... Switches on all the genes we need for inflammation during an immune response (genes for cytokines, gene for complement) ...
Genes associated with X-linked conditions are located on the X chromosome, which is one of the two sex chromosomes. . A ... have an autosomal recessive pattern. of inheritance. In autosomal recessive inheritance, both copies of the gene in each cell ... Additionally, mutations in one gene, ADGRG1, have been found to cause a severe form of the condition called bilateral ... which means one copy of the altered gene in each cell is sufficient to cause the disorder. Other forms of polymicrogyria appear ...
These are characters only expressed in one sex. They may be caused by genes on either autosomal or sex chromosomes. Examples: ... the first sex-linked gene discovered. Fur color in domestic cats: the gene that causes orange pigment is on the X chromosome; ... sex chromosome) of the individual. In autosomal chromosomes both sexes have the same probability of existing (see Fishers ... while the male is the heterogametic sex, with one X and one Y chromosome (XY). Genes on the X or Y chromosome are called sex- ...
Autosomal means that the mutated, or abnormal, gene is located on one of the numbered, or non-sex, chromosomes. Dominant ... or non-sex, chromosomes. Recessive means that two copies of a mutated gene must be present to cause the disease. Dyskeratosis ... Describes the loss of one of the two number 7 chromosomes. Mono means one and somy comes from the word chromosome. A ... dominant gene search for term The gene that always expresses itself over a recessive gene. A person with a dominant gene for a ...
In these cases the two alleles are autosomal (not sex chromosomes). Other disorders are recessive, but because they are located ... on a chromosome. Usually alleles are sequences that code for a gene, but sometimes the term is used to refer to a non-gene ... Genetic disorders are normally caused by the acquisition of two recessive alleles for a single-gene trait. Genetic disorders ... An example is the gene for blossom colour in many species of flower - a single gene controls the colour of the petals, but ...
... genes,medicine,medical news today,latest medical news,medical newsletters,current medical news,latest medicine news ... This gene, located on the pseudo-autosomal region 1 of the sex chromosomes, encodes the last enzyme of melatonin synthesis. ... Recent research indicates that a low melatonin level, caused by a primary deficit in gene activity (AMST), is a risk factor for ... Surprisingly, a mutation of a single copy of SHANK3 at chromosome 22q13 is sufficient to induce language impairment, learning ...
In autosomal dominant inheritance, a single abnormal gene on one of the autosomal chromosomes (one of the first 22 non-sex ... If both parents have OI caused by an autosomal dominant gene change, there is a 75% chance that the child will inherit one or ... Chromosome -A microscopic thread-like structure found within each cell of the human body and consisting of a complex of ... In autosomal dominant inheritance, a single abnormal gene on one of the autosomal chromosomes (one of the first 22 "non-sex" ...
In females who have one copy of the defective gene that causes NDI, the normal copy of the gene on the other X chromosome can ... compared to females who inherit two X chromosomes. Autosomal mutations are located on one of the 22 non-sex chromosomes. Males ... X-linked mutations are carried on the X chromosome, which is one of the two sex chromosomes. Females have two X chromosomes, ... Inherited NDI is caused by defects in the AVPR2 or AQP2 genes. NDI can be inherited in an X-linked or an autosomal fashion. ...
... the role of sex chromosomes in autoimmunity remains unclear (6, 7).. Sex chromosomes can cause differences in gene expression ... The Y chromosome has evolved from an autosomal ancestor to primarily include genes involved in male reproduction, with only a ... Sex differences can be due to sex hormones, sex chromosomes, or both (6). While the role of sex hormones has been well studied ... A) Diagrams of the sex chromosomes used in the breeding of XY*x (XO) mice. The Y* chromosome is a rearranged Y chromosome with ...
Caused in errors in. Autosomal vs. sex chromosomes. Sex chromosomes: responsible for gender determination (2). Autosomes: any ... Sex-linked traits. Genes that occurs on the x chromosome and not on the y chromosome. Hemophilia, color blindness, glucose-6- ... chromosome not considered a sex chromosome (44). Sex determination. Humans. XX is female. XY is male (father determines sex of ... Why are linked genes?. Close together on the same chromosome, they do not assort independently Gene duplication. A portion of ...
Autosomal disease- A disease caused by a gene located on a chromosome other than a sex chromosome (autosomal chromosome). ... Genetic testing is performed on chromosomes, genes, or gene products to determine whether a mutation is causing or may cause a ... Sex-linked disorder- A disorder caused by a gene located on a sex chromosome, usually the X chromosome. ... also contain important genes. Some genetic diseases are caused by missing or altered genes on one of the sex chromosomes. Males ...
Single gene disorders, like Huntingtons disease and cystic fibrosis, actually follow Mendelian inheritance patterns. ... X Chromosome-Linked Recessive Single-Gene Diseases. Single-gene diseases that involve genes found on the sex chromosomes have ... Autosomal dominant polycystic kidney disease can be caused by mutations in either the polycystic kidney disease 1 (PKD1) gene ... the PKD1 gene is located on human chromosome 16, whereas the PKD2 gene is located on human chromosome 4. ...
The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes (autosomes) and ... This state of having two different variants of the same gene on each chromosome is originally caused by a mutation in one of ... Main article: Sex linkage. In humans and other mammal species, sex is determined by two sex chromosomes called the X chromosome ... Genetic traits on the X and Y chromosomes are called sex-linked, because they are linked to sex chromosomes, not because they ...
If unsynapsed autosomal segments contain a gene or genes crucial for meiosis, those genes will be silenced, causing meiotic ... An introduction to sex chromosome activity in spermatogenesis. The transcriptional activity of the sex chromosomes varies ... The mouse X chromosome is enriched for sex-biased genes not subject to selection by meiotic sex chromosome inactivation. Nat. ... with the ensuing expression of sex-linked genes causing meiotic arrest. (D) In XX females, all chromosomes have homologues and ...
The other genes that cause PDC deficiency are not located on the sex chromosomes, so they are called autosomal genes.[1][3] We ... sex chromosomes. ; males have one X chromosome. and one Y chromosome, and females have two X chromosomes. Males therefore have ... This is called autosomal recessive inheritance. People who have only one changed copy of an autosomal gene that causes PDC ... People with changes in both copies of the autosomal genes that cause PDC deficiency have symptoms of the disease. ...
Autosomal disorders are disorders caused by variations in genes located on non-sex chromosomes (sex chromosomes are the X and Y ... Causes. Hemophilia B is caused by mutations in the F9 gene. The F9 gene is located on the X chromosome and thus is inherited as ... X-linked recessive disorders are conditions caused by an altered gene on the X chromosome. Females have two X chromosomes (XX ... Males with an X chromosome containing the disorder-causing gene will pass that gene on to all of their daughters. These ...
2010) Nucleotide diversity in Silene latifolia autosomal and sex-linked genes. Proc Roy Soc B-Biol Sci 277:3283-3290. ... Haploid Selection Favors Suppressed Recombination Between Sex Chromosomes Despite Causing Biased Sex Ratios ... 2001) Sex from W to Z: Evolution of vertebrate sex chromosomes and sex determining genes. J Exp Zool 290:449-462. ... Gene loss during plant sex chromosome evolution has not yet been assessed, because sex-linked genes have been ascertained ...
A single abnormal gene on one of the first 22 nonsex (autosomal) chromosomes from either parent can cause an autosomal disorder ... Inheriting a disease, condition, or trait depends on the type of chromosome affected (nonsex or sex chromosome). It also ... Dominant inheritance means an abnormal gene from one parent can cause disease. This happens even when the matching gene from ... In an autosomal dominant disease, if you inherit the abnormal gene from only one parent, you can get the disease. Often, one of ...
... races since its main cause is the inheritance in an autosomal recessive pattern which has no relations with the sex chromosomes ... The gene that contributes to the cause of Hunter syndrome is residing on the X-recessive chromosome. Since males only have one ... The main cause of this accumulation is the absence of iduronate sulfatase enzyme. Some of the signs for recognition of the ... Hurler Syndrome is an inherited disease and is caused by a recessive mutation (both parents would need to have passed down the ...
These genetic diseases are diseases caused by an error in a single DNA gene. Autosomal means the errors occurs on chromosome 1 ... because an autosomal error is unrelated to the sex chromasomes. Double-dominance: Even though only one damaged gene copy causes ... Inheritance patterns for autosomal dominance: This refers to diseases where the error is in one of the autosome chromosomes, ... Generally speaking, a dominant disease affects a gene for a structural protein, causing malformed proteins that cause disease ...
To date, defects in 6 genes are known to cause the syndrome. Irritability, erratic sleep, and fever are some symptoms. ... Autosomal disease indicates that the condition is passed from one generation to the next through one of the 23 chromosomes ( ... Defects in this gene results in the immune response. TREX1 is located on chromosome 3 and is also called AGS1. TREX1 encodes ... autosomes) and not the sex chromsomes (X or Y).. The Aicardi-Goutieres Syndrome is observed in infants within 4 months of birth ...
Causes of hair loss and baldness through hormones, stress, and genes. Read more at Bernstein Medical. ... or Y-chromosomes are called sex-linked. Genes on the other 22 pairs of chromosomes are called autosomal. It is currently ... Genes. A gene is a single bit of chemically encoded hereditary instruction that is located on a chromosome and represents a ... A "recessive" gene means that both genes must be present in order for the trait to be expressed. The genes involved in ...
  • Usually alleles are sequences that code for a gene , but sometimes the term is used to refer to a non-gene sequence. (bionity.com)
  • An individual's genotype for that gene is the set of alleles it happens to possess. (bionity.com)
  • An example is the gene for blossom colour in many species of flower - a single gene controls the colour of the petals , but there may be several different versions (or alleles) of the gene. (bionity.com)
  • The resulting colour of an individual flower will depend on which two alleles it possesses for the gene and how the two interact. (bionity.com)
  • An organism which has two different alleles of the gene is called heterozygous . (bionity.com)
  • There are two equations for the frequency of two alleles of a given gene (see Hardy-Weinberg principle ). (bionity.com)
  • The following equation (commonly termed the Lee equation) can be used to calculate the number of possible genotypes in a diploid organism for a specific gene with a given number of alleles. (bionity.com)
  • where a is the number of different alleles for the gene being dealt with and G is the number of possible genotypes. (bionity.com)
  • Gene interaction and, particularly, interaction between different alleles at different genes. (bmj.com)
  • Alternatively, the fetus can inherit a single defective gene from one parent and the remaining normal copy becomes damaged by environmental causes such as a viral infection or exposure to DNA damaging agents. (medindia.net)
  • females with a defective gene on one X chromosome are protected from its effects by the normal gene on the other X chromosome but have a 50 percent chance of passing the defective gene on to their offspring. (britannica.com)
  • For women to show the defect, both of their X chromosomes have to carry the defective gene, a rare occurrence. (thefreedictionary.com)
  • If the parent has one good copy of the gene and one defective copy, the parent will not have MPS and may be unaware that he or she has a defective gene. (healthofchildren.com)
  • Normally this is not a problem when a single imperfect gene exists but when each parent passes on the same recessive defective gene or an imperfect dominant gene is passed on the baby may develop a birth defect. (prezi.com)
  • Comparative genomic analysis of CaT2 indicated that four candidate genes, all of which encode glycosyltransferase, were involved in aggregation of CaT2. (jove.com)
  • To equate SD with g/h-SD is erroneous because in recent years numerous sceintific article have been reporting genomic-DNA sex differences that are neither gonadal nor hormonal. (bio.net)
  • Until scientists (including neuroscientists and behavioralists) acknowledge and research possible ramifications of these sex differences, many possible genomic-DNA contributors to sexual- and/or gender- orientation shall be overlooked. (bio.net)
  • A. The presumption that SD is the equivalent g/h-SD is erroneous and misleading, because there are genomic sex differences (other than lack of or presence of SRY) that are neither gonadal nor hormonal. (bio.net)
  • Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. (springer.com)
  • Each chromosome has one copy of many different genes. (chop.edu)
  • The origins and divergence of Drosophila simulans and close relatives D. mauritiana and D. sechellia were examined using the patterns of DNA sequence variation found within and between species at 14 different genes. (genetics.org)
  • Children randomly get one of each pair of chromosomes from their mother and one of each pair from their father. (cdc.gov)
  • The Gallus gallus Z chromosome provides a useful opportunity to study the importance and trade-offs between sex-specific selection and dosage compensation in shaping the evolution of the genome as it shows incomplete dosage compensation and is also present twice as often in males than females, and therefore predicted to be enriched for male-biased genes. (genetics.org)
  • We previously demonstrated that genome reorganization, through chromosome territory repositioning, occurred concurrently with significant changes in gene expression in normal primary human fibroblasts. (bioportfolio.com)