Why We Age - The DNA and Genetic Theories
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April 29, 2007 |
2. The DNA and Genetic Theories
Shortening of the telomeres within the cells
Telomeres are the tiny "caps" that keep our chromosomes from fusing together. When we are young, the telomeres are very long. Scientists theorize that telomeres may serve as genetic "clocks." As we grow and age, our cells divide. One parent cell divides into two daughter cells, making copies of the genetic information to pass on to these new cells. Each time a cell divides and the DNA within the cell is copied, the telomeres shorten.
This process continues until the telomeres reach a critical length, at which point the cell stops dividing. Once a cell stops dividing, it may do one of three things: die, become inactive, or transform into some sort of abnormality, such as a cancerous cell.
A 2003 study published in The Lancet links the lengths of telomeres with rate of survival among people over 60, the first study to make this connection. Researchers from the University of Utah recently demonstrated an association between telomere shortening and mortality rate. Their study measured telomeres in a group of subjects who donated blood in the mid-1980s. The researchers then compared the telomere lengths to survival data they had gathered on these subjects. They found that subjects with shorter telomeres were more than three times as likely to have died of heart disease, and more than eight times as likely to have died of infectious disease as their counterparts with longer telomeres. 
Look out tomorrow for the third of the current theories on why we age.Labels: anti-aging |
posted by Maggie @ 1:00 pm   |
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