Telomere
From EvoWiki
A telomere is a segment at the end of each chromosome consisting of a series of repeated DNA sequences that regulate chromosomal replication during each division. The sequence is highly conserved across groups of organisms. For example, in vertebrates, the sequence is TTAGGG.
Chromosomes are shortened as they are replicated, because the DNA polymerase complex starts replicating their DNA a short distance from the end. If shortened too much as a result of repeated divisions, important genes can be lost. However, an enzyme called telomerase can extend the telomeres, keeping that calamity from happening. But by doing so, telomerase can help cancer cells divide uncontrollably. So this would-be Fountain of Youth can be an enabler of cancer.
Here's an animation of telomerase in action
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This page is part of the EvoWiki encyclopedia of genetics and molecular biology. Topics: Genetics - Transmission genetics - Molecular genetics - Population genetics - Quantitative genetics - Molecular biology - Genomics |
