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What are telomeres?

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Quick answer

Telomeres are protective caps at the ends of your chromosomes, like the plastic tips on shoelaces. They keep DNA from fraying, but they shorten each time a cell divides — a process tied to aging and to how many times a cell can replicate.

Key things to understand

  1. Repeated DNA sequences that shield chromosome ends from damage and accidental fusion.
  2. They get a little shorter with every cell division.
  3. When too short, the cell stops dividing (senescence) or dies — a driver of aging.
  4. An enzyme called telomerase can rebuild them; it's very active in stem cells and most cancers.

People also ask

Do telomeres cause aging?
Telomere shortening is one driver of cellular aging, but aging is complex and involves many other factors too.
What is telomerase?
An enzyme that lengthens telomeres. It keeps stem and reproductive cells young — and is hijacked by cancers to divide endlessly.
Can you lengthen your telomeres?
Lifestyle factors like exercise, less stress, and good sleep are linked to slower shortening, but no proven, safe method reliably lengthens them in humans.