| MGCR | meningioma chromosome region |
|---|---|
| MOMX | macroorchidism-marker X chromosome [syndrome] |
| MTACR | multiple tumor-associated chromosome region |
| 2n | haploid chromosome; diploid |
| PCC | Pasteur Culture Collection; percutaneous cecostomy; pheochromocytoma; phosphate carrier compound; pl... |
| 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) |
|---|---|
| chromosome walking | A procedure to find and sequence a gene whose approximate position in a chromosome is known by classical genetic linkage studies. Starting with the known sequence of a gene shown by classical genetics to be near to the novel gene, new clones are picked from a genomic library by hybridisation with a short probe generated from the appropriate end of the known sequence. The new clones are then sequenced, new probes generated and the process repeated until the gene of interest is reached. (18 Nov 1997) |
| Philadelphia chromosome | <genetics, oncology> Characteristic chromosomal abnormality in which a portion of chromosome 22 is translocated to chromosome 9. This abnormality is found in nearly all cases of chronic myeloid leukaemia and some cases of acute lymphoblastic leukaemia. (30 Sep 1997) |
| mitochondrial chromosome | The DNA component of mitochondria, the chief function of which is synthesis of adenosine triphosphate and the management of cellular energy; the chromosome contains some 16,000 base pairs arranged in a circle. The inheritance is matrilineal, and the mutation rate is unusually high; since each cell contains thousands of copies a mutant form may assume an almost continuous gradation as in a galtonian process. Most of the mutations known have their impact on the respiratory chain. (05 Mar 2000) |
| monocentric chromosome | <genetics, molecular biology> Chromosome with a single centromere, i.e. most chromosomes. (18 Nov 1997) |
| w chromosome | <genetics> A sex chromosome found in all birds and certain other animals where the female is the heterogametic sex. The W chromosome causes the individual to become female in bird species. It is part of the WZ set of sex chromosomes, where the female has one W chromosome and one Z chromosome, and the male has two Z chromosomes. (09 Oct 1997) |
| polytene chromosome | <cell biology> Giant chromosomes produced by the successive replication of homologous pairs of chromosomes, joined together (synapsed) without chromosome separation or nuclear division. They thus consist of many up to 1000) identical chromosomes (strictly chromatids) running parallel and in strict register. The chromosomes remain visible during interphase and are found in some ciliates, ovule cells in angiosperms and in larval Dipteran tissue. The best known polytene chromosomes are those of the salivary gland of the larvae of Drosophila melanogaster which appear as a series of dense bands interspersed by light interbands, in a pattern characteristic for each chromosome. The bands, of which there are about 5,000 in Drosophila melanogaster, contain most of the DNA (ca 95%) of the chromosomes and each band roughly represents one gene. The banding pattern of polytene chromosomes provides a visible map to compare with the linkage map determined by genetic studies. Some segments of polytene chromosome show chromosome puffs, areas of high transcription. (18 Nov 1997) |
| harlequin chromosome | <cell biology> A chromosome which, when stained, produces a banded pattern of alternating light and dark segments (also called a harlequin pattern). It is made by treating a cell with 5'-bromodeoxyuridine, the chemical incorporates into the cells DNA and when stained is lighter than the DNA around it. (09 Oct 1997) |
| heterotypical chromosome | <genetics> One or more chromosomes that can be distinguished from autosomes by their morphology and behaviour. Synonym: accessory chromosome, heterochromosome, sex chromosome. (18 Nov 1997) |
| X chromosome | <genetics> A sex chromosome. In mammals paired in females (XX), in amphibia paired in males. (11 May 1997) |
| homologous chromosome | <genetics> A pair of chromosomes containing the same linear gene sequences, each derived from one parent. The chromosomes tend to pair or synapse during mitosis. (14 Oct 1997) |
| sex chromosome | <genetics> Chromosome that determines the sex of an animal. In humans, where the two sex chromosomes (X and Y) are dissimilar, the female has two X chromosomes and the male is heterogametic (XY). <zoology> In birds, the opposite is the case, the male being XX and the female XY, in many organisms, there is only one sex chromosome and one sex is XX, the other X0. A portion of the X and Y chromosomes is similar and is known as the pseudoautosomal region. (14 Oct 1997) |
| sex chromosome imbalance | Any abnormal pattern of sex chromosomes; e.g., XXY in men with seminiferous tubule dysgenesis, XO in women with Turner's syndrome; rarer patterns of imbalance are XXX, XXXY, and XYY. See: isochromosome. (05 Mar 2000) |
| submetacentric chromosome | A chromosome with the centromere so placed that it divides the chromosome into two arms of strikingly unequal length. (05 Mar 2000) |
| nucleolar chromosome | A chromosome regularly associated with a nucleolus. (05 Mar 2000) |