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17 April 2014 12:48 pm ,
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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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For Chromosomes, Size Does Matter
31 January 2003 (All day)
Want to live longer? Eat your vegetables, don't smoke, and don't play in traffic. And according to a new study, you should hope you're endowed with ample stretches of DNA called telomeres at the ends of your chromosomes. The study is the first to link telomere length to longevity in humans and could yield new strategies for combating age-related ills.
Telomeres--repeating segments of DNA on the ends of chromosomes--are often likened to the plastic caps that prevent shoelaces from fraying. The molecules don't contain genes, but they protect chromosomes from damage. Telomeres' initial length varies among individuals, but in everyone, they become shorter over time. Cell-culture studies show that when telomeres can no longer shield chromosomes from damage, cells stop dividing or become unstable. And recently, researchers have learned that people with a genetic disorder that accelerates aging have abnormally short telomeres, further implicating telomeres in aging.
But do longer telomeres mean longer life in normal circumstances? To find out, geneticist Richard Cawthon and colleagues at the University of Utah in Salt Lake City examined telomere lengths in 143 elderly men and women who had provided blood samples more than 15 years earlier. In the 1 February issue of The Lancet, the team reports that participants with shorter-than-average telomeres died 4 to 5 years younger than did those with longer telomeres and were more than three times as likely to have died from heart disease. Participants with the shortest telomeres (the bottom 25%) were more than eight times as likely to die of infectious disease as those with longer telomeres.
This is "the first hint that telomeres might limit people's lives, says molecular biologist Jerry Shay of the University of Texas Southwestern Medical Center in Dallas. Still, he cautions that more research--using many more participants--is needed to understand the link. For instance, Cawthon points out, it's important to learn whether telomere shortening actually causes disease or is just a side-effect of something else. Resolving that question, he says, will likely help researchers identify and thwart processes that cause age-related illness.