| breast cancer susceptibility genes | Inherited factors that predispose to breast cancer. Put otherwise, these genes make one more susceptible to the disease and so increase the risk of developing breast cancer. Two of these genes, BRCA1 and BRCA2, have been identified (and prominently publicised). Several other genes (those for the Li-Fraumeni syndrome, Cowden disease, Muir-Torre syndrome, and ataxia-telangiectasia) are also known to predispose to breast cancer. However, since all of these known breast cancer susceptibility genes together do not account for more than a minor fraction (1/5th at most) of breast cancer that clusters in families, it is clear that more breast cancer genes remain to be discovered. (12 Dec 1998) |
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| cancer, breast, susceptibility genes | Inherited factors that predispose to breast cancer. Put otherwise, these genes make one more susceptible to the disease and so increase the risk of developing breast cancer. Two of these genes, BRCA1 and BRCA2, have been identified (and prominently publicised). Several other genes (those for the Li-Fraumeni syndrome, Cowden disease, Muir-Torre syndrome, and ataxia-telangiectasia) are also known to predispose to breast cancer. However, since all of these known breast cancer susceptibility genes together do not account for more than a minor fraction (1/5th at most) of breast cancer that clusters in families, it is clear that more breast cancer genes remain to be discovered. (12 Dec 1998) |
| genes, breast cancer susceptibility | Inherited factors that predispose to breast cancer. Put otherwise, these genes make one more susceptible to the disease and so increase the risk of developing breast cancer. Two of these genes, BRCA1 and BRCA2, have been identified (and prominently publicised). Several other genes (those for the Li-Fraumeni syndrome, Cowden disease, Muir-Torre syndrome, and ataxia-telangiectasia) are also known to predispose to breast cancer. Howeverm, since all of these known breast cancer susceptibility genes together do not account for more than a minor fraction (1/5th at most) of breast cancer that clusters in families, it is clear that more breast cancer genes remain to be discovered. See related entries to: BRCA1; BRCA2; Breast cancer, familial. (12 Dec 1998) |
| banding of chromosomes | Treatment of chromosomes to reveal characteristic patterns of horizontal bands. Thanks to these banding patterns that resemble bar codes, each human chromosome is distinctive and can be identified without ambiguity. (12 Dec 1998) |
| reduction of chromosomes | The process during meiosis whereby one member of each homologous pair of chromosomes is distributed to a sperm or ovum; the diploid set of chromosomes (46 in humans) is thus reduced to the haploid set in each gamete; union of the sperm and ovum then restores the diploid or somatic number in the one-cell zygote. (05 Mar 2000) |
| ring chromosomes | Aberrant chromosomes with no ends. (12 Dec 1998) |
| chromosomes | The self-replicating genetic structures of cells containing the cellular DNA that bears in its proteins. (09 Oct 1997) |
| chromosomes, archaeal | Structures within the nucleus of archaeal cells consisting of or containing DNA, which carry genetic information essential to the cell. (12 Dec 1998) |
| chromosomes, bacterial | Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell. (12 Dec 1998) |
| chromosomes, fungal | Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell. (12 Dec 1998) |
| chromosomes, human | The structures within the human cell nucleus that contain the hereditary material, DNA. There are 46 chromosomes normally present in the human, including two which determine the sex of individual, xx for the female and xy for the male. Human chromosomes are classified into groups sharing structural similarity in terms of length from the centromere. (12 Dec 1998) |
| chromosomes, human, 1-3 | One of the seven groups of chromosomes containing three pairs conventionally named pairs 1, 2, and 3. The chromosomes in this group, also called group a, are large chromosomes with centromeres approximately in the middle. (12 Dec 1998) |
| chromosomes, human, 13-15 | The fourth of the seven groups of chromosomes containing three pairs conventionally named pairs 13, 14, and 15. The chromosomes in this group, also called group d, are medium sized with centromeres in the acrocentric position. (12 Dec 1998) |
| chromosomes, human, 16-18 | The fifth of the seven groups of chromosomes containing three pairs conventionally named pairs 16, 17, and 18. The chromosomes in this group, also called group e, are rather short and submetacentric. (12 Dec 1998) |
| chromosomes, human, 19-20 | The sixth of the seven groups of chromosomes containing two pairs conventionally named pairs 19 and 20. The chromosomes in this group, also called group f, are short and metacentric. (12 Dec 1998) |