Telomere enzyme a likely key to longevity

A new experiment suggests that the enzyme telomerase can extend the lifespan of mice by about 26 percent.

I thought this was a good explanation of what telomeres are and what telomerase does:

Telomerase lengthens telomeres — the “caps” on the end of chromosomes that protect DNA from damage. Like burning fuses, telomeres normally get shorter each time that most body cells divide. After a certain number of divisions, the telomeres in the daughter cells become too short and the chromosomes start to degrade, thus preventing the cells from dividing any further. So this shortening of telomeres places a limit on the number of times that most body cells can divide, the so-called Hayflick limit.

Telomerase enables the cell to divide indefinitely by adding back the bit of telomere lost during each cell division, essentially keeping the fuse from burning. Previous research has shown that adding an active copy of the telomerase gene to human cells causes those cells to surpass the Hayflick limit and apparently divide without end. But people with longer telomeres don’t necessarily live any longer than people with short telomeres do, so evidence for a link with lifespan has been fuzzy.

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