telomere (t l -mîr , t l -) Either of the sections of DNA occurring at the extreme ends of each chromosome in a eukaryotic cell. Telomeres consist of highly repetitive sequences of DNA that do not code for proteins, but function as caps to keep chromosomes from fusing together. The length of the telomere influences the stability of genetic information just interior of the telomere, since the nucleotide sequences at the ends of a chromosome are not copied by DNA polymerase. Successive copying can thus shorten telomeres, sometimes to the point that functional genes near the telomeres are lost, and this may play a role in cellular senescence and age-related diseases. In germ cells, stem cells, and some cancer cells, shortened telomeres can be extended by the enzyme telomerase, thus keeping both the telomeres and the genes near them functioning. Most somatic cells do not express telomerase, and the shortening of telomeres during each round of cell division may be part of the natural aging of cells. |
ThesaurusLegend: Synonyms Related Words Antonyms | Noun | 1. | telomere - either (free) end of a eukaryotic chromosome; "telomeres act as caps to keep the sticky ends of chromosomes from randomly clumping together"chromosome - a threadlike strand of DNA in the cell nucleus that carries the genes in a linear order; "humans have 22 chromosome pairs plus two sex chromosomes" end, terminal - either extremity of something that has length; "the end of the pier"; "she knotted the end of the thread"; "they rode to the end of the line"; "the terminals of the anterior arches of the fornix" |
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