New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Telomere

A telomere is a region of highly repetitive DNA at the end of a linear chromosome that functions as a disposable buffer. Every time linear chromosomes are replicated during late S phase, the DNA polymerase complex is incapable of replicating all the way to the end of the chromosome; if it were not for telomeres, this would quickly result in the loss of vital genetic information, which is needed to sustain a cell's activities. Every time a cell with linear chromosomes divides, it will lose a small piece of one of its strands of DNA. This process has been referred to by James Watson and Alexei Olovnikov as the "end replication problem." It is believed that telomeres have a function in the ageing process. Telomerase is a "ribonucleoprotein complex" composed of a protein component and an RNA primer sequence which acts to protect the terminal ends of chromosomes. This is because during replication, DNA polymerase can only synthesize DNA in a 5'to 3'direction and can only do so by adding polynucleotides to an RNA primer that has already been placed at various points along the length of the DNA. These RNA strands must later be replaced with DNA. At the terminal of the DNA strand, the RNA primer is laid but DNA polymerase cannot extend beyond it. This RNA primer will not later be replaced by DNA, and therefore cannot be translated into gene products or replicated later. Without telomeres at the end of DNA, this genetic sequence would be deleted and the chromosome would grow shorter and shorter in subsequent replications. The telomere prevents this problem by employing a different mechanism to synthesize DNA at this point, thereby preserving the sequence at the terminal of the chromosome.

Related Stories
 


Health & Medicine News

August 1, 2025

Ape behavior just got a name upgrade — “scrumping” — and it might help explain why humans can handle alcohol so well. Researchers discovered that African apes regularly eat overripe, ...
Women who drank heavily, even though they strongly wished to avoid pregnancy, were 50% more likely to become pregnant than those who drank little or not at all, according to new research. Surprisingly, cannabis use didn t show the same ...
In an exciting breakthrough, researchers have identified cancer drugs that might reverse the effects of Alzheimer's disease in the brain. By analyzing gene expression in brain cells, they discovered that some FDA-approved cancer medications could ...
GLP-1 drugs like Ozempic are transforming weight loss, but a new UVA study warns they're not improving a critical measure of health: cardiorespiratory fitness. While these medications help people shed fat, they also strip away vital muscle mass ...
Stepping into a virtual forest or waterfall scene through VR could be the future of pain management. A new study shows that immersive virtual nature dramatically reduces pain sensitivity almost as ...
Potent statins are the best-proven weapon against heart disease, especially when paired with lifestyle changes. Most people aren’t active enough—and many are underdiagnosed—so starting treatment strong is ...
A newly mapped neural circuit shows how our skin senses cool temperatures and sends that info to the brain, revealing an unexpected amplifier in the spinal cord and offering insight into cold-related ...
A group of Australian scientists has uncovered a new way to fight some of the toughest cancers by targeting an overlooked cellular process called minor splicing. This tiny but vital mechanism turns out to be essential for the growth of certain ...
A new global study reveals a striking post-pandemic surge in gut-brain disorders like IBS and functional dyspepsia. Researchers compared data from 2017 and 2023 and discovered sharp increases—IBS up 28% and dyspepsia nearly 44%. Those suffering ...
Scientists at Kyoto University have developed a groundbreaking "lung-on-a-chip" that can mimic the distinct regions of human lungs—airways and alveoli—to study how viruses like COVID-19 affect them differently. Powered by isogenic induced ...
A global study of over 88,000 adults reveals that poor sleep habits—like going to bed inconsistently or having disrupted circadian rhythms—are tied to dramatically higher risks for dozens of diseases, including liver cirrhosis and gangrene. ...
Scientists at Columbia Engineering have developed an injectable hydrogel made from yogurt-derived extracellular vesicles (EVs) that could revolutionize regenerative medicine. These EVs serve both as healing agents and as structural components, ...

Latest Headlines

updated 12:56 pm ET