| chromosome disorder | An abnormal condition due to an abnormality of the chromosomes. For example, Down syndrome (the genetic abnormality featuring three chromosome 21s, instead of two, also refered to as trisomy 21) is a chromosome disorder. (12 Dec 1998) |
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| chromosome fragile sites | Heritable sensitive regions of chromosomes which show up in vitro as non-staining bands. They are associated with chromosome breakage and other aberrations, and, when located on sex chromosomes, they produce phenotypic abnormalities. No abnormal phenotype has been definitely identified with autosomal fragile sites, but some rare autosomal recessive disorders may be due to homozygosity for fragile sites. Fragile sites are designated by the letters "fra" followed by the designation for the specific chromosome and locus. (12 Dec 1998) |
| chromosome map | The chart of the linear array of genes on a chromosome. The Human Genome Project aims to map all of the human chromosomes. (12 Dec 1998) |
| chromosome mapping | The mapping of the relative locations of genes on a chromosome by analysing linkage frequencies (how often different genes are inherited together) and crossover frequencies (how often different combinations of three or more genes are inherited) or recombination frequencies. (09 Oct 1997) |
| chromosome mosaicism | See: mosaic. (05 Mar 2000) |
| chromosome painting | Application of in situ hybridisation to determine chromosomal location of genes using fluorescently tagged probes. (18 Nov 1997) |
| chromosome pair | Two chromosomes of the full diploid karyotype that are similar in form and function but that usually differ in content, one normally being inherited from each parent and one being transmitted to each progeny; in the heteromorphic sex (in humans, the male), one pair, the sex chromosomes, differ markedly in appearance, content, and function. (05 Mar 2000) |
| chromosome pairing | The process in synapsis whereby homologous chromosome's align opposite each other before disjoining in the formation of the daughter cell; the apposition permits exchange of genetic material in crossing-over. (05 Mar 2000) |
| chromosome puffs | Expansions of particular chromosome regions; sites of RNA syntheses. (05 Mar 2000) |
| chromosome rosette | Right before metaphase, human chromosomes briefly form this single ring structure. (09 Oct 1997) |
| chromosome rosette john jordan | Right before metaphase, human chromosomes briefly form this single ring structure. (09 Oct 1997) |
| chromosome satellite | A small chromosomal segment separated from the main body of the chromosome by a secondary constriction; in humans it is usually associated with the short arm of an acrocentric chromosome. (05 Mar 2000) |
| chromosome segregation | <cell biology> The orderly separation of one copy of each chromosome into each daughter cell at mitosis. (18 Nov 1997) |
| chromosome synapsis | <cell biology> The close apposition of homologous chromosomes before cell division or permanently in giant polytene chromosomes. (18 Nov 1997) |
| chromosome translocation | <cell biology> The fusion of part of one chromosome onto part of another. Largely sporadic and random, there are some translocations at hot spots that occur often enough to be clinically significant. See: Philadelphia translocation. (18 Nov 1997) |