DNA Research Reveals Lifespan Link
Researchers from the Universities of Exeter and Glasgow have determined in a study of the DNA of a captive population of zebra finches (Taeniopygia guttata), that just one specific piece of genetic material in a bird’s cells can reveal how long it is likely to live.
Called telomeres, these portions of DNA (deoxyribonucleic acid) which mark the ends of chromosomes are found in almost all higher animals and plants. Telomeres help to protect the ends of chromosomes as they divide, preventing them from fusing with one another, or unraveling. After time, telomere ends become shorter and no longer protect chromosomes, resulting in cell damage and deterioration.
It has long been suspected that telomeres decline and the ageing process are closely linked, but this has not been proven in humans, and studies thus far have relied on limited monitoring during a lifespan. This recent study started measuring telomere length when the zebra finches were twenty-five days old and continued periodically over the course of the birds’ lives. The results, which were published this week in Proceedings of the National Academy of Sciences, revealed a close association between telomere length and longevity. Although the results in this study are very convincing, ecologist Pat Monaghan of the University of Glasgow notes that this does not necessarily hold true for humans, and telomere researcher Duncan Baird of Cardiff University agrees.
Zebra finches were chosen for the study as they breed well in captivity and have an average lifespan of nine years, allowing researchers to draw conclusions in a relatively short space of time when compared to humans, while at the same time not being as short-lived as mice. A total of ninety-nine finches were used in the study and it was noted that the association between lifespan and telomere length was strongest at twenty-five days of age. This is a time in the bird’s life when it is almost fully grown, but still sexually immature and reliant of its parents for sustenance. This age would be roughly equivalent to a prepubescent human.
More research needs to be done to determine the significance of the results, as it is known that telomere length is not exclusively genetically determined and can be shortened by stressful events. Baird also noted that the data doesn’t reveal whether telomeres are driving the ageing process. Moreover, the results were for the entire population of birds being monitored, individual results may present a different picture.