16 January 2012
ByAppeared in BioNews 640
Analysis of person's DNA when they are still young could provide important clues about how long they will live, if a study on zebra finches is anything to go by. Research shows that the best indicator of the birds' longevity is the length of a section of genetic code at the end of their chromosomes, called the telomere.
The telomere acts as a protective cover for the DNA strand, like a plastic cap at the end of a shoelace. Whenever a cell divides, part of the telomere wears away, and when there is no protective cap remaining, the cell starts to malfunction. The DNA then deteriorates, leading to an increased likelihood of diseases such as cancer. A longer telomere means that cells have more protection.
Professor Pat Monaghan and her team at the UK's University of Glasgow tracked 99 zebra finches over their lifetimes, which ranged from 210 days to nine years. They took regular blood tests from the birds to determine telomere length and other factors. The length of the telomere most closely predicted the finches' lifespan when they were just 25 days old. Professor Monaghan suggested to Fox News that this would be equivalent to an age just before puberty in humans.
However, the findings, published in the journal PNAS (Proceedings of the National Academy of Sciences), may not be directly applicable to humans yet. Dr Duncan Baird, a telomere researcher at Cardiff University UK who was not involved in the study told Nature News that 'it's not going to be possible to translate this immediately to the human situation'. This, said Dr Baird, is because humans are 'a long-lived species' and humans live in diverse environments. Humans' longer lifespans mean that a similar study on people would be impractical.
Nevertheless, the study is important. It is the first time that many individuals of any species have been tracked throughout their lifetimes. Previous studies have either compared different individuals across a variety of ages, or only followed a group over short periods of time.
A telomere researcher at the Spanish National Cancer Research Centre in Madrid, María Blasco pointed out in Nature News that 'it's the first time that normal differences in telomere length have been shown to be predictive of longevity'. Although not involved in the study, she is also a promoter of telomere length for determining lifespan for a company called Life Length.