Wednesday, March 13, 2013

Telomeres and Life Expectancy

(Credit: NHGRI)

Did you ever want to know how much life you have left to live?

I certainly don't, its a threatening thing to know and it takes all the excitement out of death. Nevertheless, scientists have discovered a link between the length of your telomeres and life expectancy. Telomeres protect the coding sections of DNA by providing a buffer zone to be cut slightly shorter each time a cell divides. When the whole telomere is used, the cell stops dividing and just gets older, eventually degrading whatever body system it is a part of.

A 20 year long study by a team from the University of East Anglia is looking at a population of Warblers on an isolated island with no predators. They are measuring the lengths of the birds telomeres as well as their life expectancy. While findings display a correlation, it isn't strong enough to predict the life of any one individual with accuracy.

Why can't we give the life expectancy of just one warbler? To give an analogy, think of two hourglasses. While looking at the amount of sand in the top of the two hourglasses we can approximate how much is left for them; yet the size of the opening in one hourglass may differ from the other, and will take a different amount of time to drain its sand. In other words, individuals may vary in the amount of oxidative stress they are subjected to during life, and these oxidants can accelerate the degradation of telomeres.

In November, the East Angia researchers stated that "It would be virtually impossible to do such a study in humans. For one thing it would take a very long time to study a human lifespan. Also in humans we would normally, quite rightly, intervene in cases of disease, so it wouldn't be a natural study" (Dr. Richardson).

But unfortunately, they were completely wrong, as a study published last week from Salt Lake City proved that in heart disease and stroke patients, telomere length is indeed a strong predictor of survival time for the patients. The researchers also stated smoking, pollution, and lack of exercise as ways to hasten telomere shortening. 


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