New research by a team from the Universities of Glasgow and Exeter shows that a good indicator of how long individuals will live can be obtained from early in life using the length of specialised pieces of DNA called telomeres.
Telomeres occur at the ends of the chromosomes, which contain our genetic code.
They function a bit like the plastic caps at the end of shoelaces by marking the chromosome ends and protecting them from various process that gradually cause the ends to be worn away. This method of DNA protection is the same for most animals and plants, including humans, and the eventual loss of the telomere cap is known to cause cells to malfunction. This study is the first in which telomere length has been measured repeatedly from early in life of an individual and then for the rest of their natural lives. The results show that telomere length in early life is strongly predictive of lifespan.
Dr. Jon Blount in the laboratory. Photo by Simon Burt.
The researchers measured telomere lengths in small samples of blood cells taken at various ages in a group of zebra finches whose lifespan varied from just 210 days to almost nine years. The best predictor of longevity was telomere length at just 25 days. Dr Britt Heidinger from the University of Glasgow said, “While there was a lot of variation amongst individuals in telomere length, those birds that lived longest had the longest telomeres at every measurement point.”
It is known that the variation in telomere length is partly inherited, but also varies due to variation in environmental factors such as exposure to stress.
“Surprisingly, the rate of telomere wear and lifespan were not significantly influenced by diet quality in early life, or the amount which individuals invested in reproduction as adults,” said Dr Jon Blount of Biosciences at the University of Exeter, based on the Cornwall Campus.
Professor Pat Monaghan, who led the University of Glasgow team added: “Our study shows the great importance of processes acting early in life. We now need to know more about how early life conditions can influence the pattern of telomere loss, and the relative importance of inherited and environmental factors. This is the main focus of our current research.”
The study was published in Proceedings of the National Academy of Sciences. The work was funded by the European Research Council, with additional support from the UK Natural Environment Research Council, the Wellcome Trust, the US National Science Foundation, and the Royal Society.
*Source: University of Exeter