Life expectancy correlates with telomere length, which is the repeating sequence of DNA at the ends of chromosomes, determined primarily by genetics and heredity. The journal Proceedings of the National Academy of Sciences recently published an article based on data collected by scientists during years of studying wild sheep in Scotland.
Telomere length is considered an important biomarker for overall health or aging in vertebrates. The shorter they are, the higher the risk of death. Until now, however, it was not clear who influenced telomeres the most – heredity or extrinsic factors.
Answering this question requires long-term observations over the lives of many generations, but such studies are difficult to perform in humans. Therefore, scientists selected a species with a shorter lifespan to monitor – i.e. a closed population of wild sheep on the islands of Scotland.
Scientists have found that life expectancy correlates with the length of telomeres but not with their integrity, that is, the degree of deterioration. In addition, the first parameter is directly linked to genetic heredity and the second to environmental factors such as stress or diet.
“We found no evidence that telomere depletion was associated with an increased risk of death. Instead, we found that interindividual variation in mean telomere length was associated with increased lifespan. Our analysis shows that the correlation between average telomere length and individual lifespan has a genetic basis.
The authors say their discovery shows an important role genetics play in tracking lifespan and note the need for more research after looking at the evolutionary aspect of surveillance.