London: How long someone will live may be predicted by measuring their genes as early as a newborn baby, say scientists.
The Glasgow University scientists said that life expectancy is written into our DNA and is there to be seen from the day we are born.
It all depends on the length of the telomeres, which are described as 'acting like the plastic ends on shoelaces' to protect chromosomes from wear and tear.
Telomeres are being studied extensively - and are thought to hold the key to ageing.
And the longer your telomeres, the longer you will live - dependent, of course, on not dying accidentally, from disease or from lifestyle factors, the Daily Mail reported.
It was known they could be shortened by life choices, including smoking and stress. But this is the first indication that our lifespans might be predetermined from birth.
"The results of this research show that what happens in our bodies in early life is very important," said Professor Pat Monaghan, who led the Glasgow University study.
"It is not understood why there are variations of telomere length but if you had a choice, you would want to be born with longer telomeres," he said.
The study - which used zebra finches, one of Australia's most common bird species - is the first to measure telomere lengths at regular intervals through an entire life. With people, it is usually only the elderly who are studied because of the timescales involved.
Blood cell samples were taken from 99 finches, starting when they were 25 days old.
The results exceeded even the researchers' expectations. The birds with the shortest telomeres did tend to die first - from as early as seven months after the start of the trial.
But one bird in the group with the longest telomeres survived to almost nine years old.
The results hold huge implications for humans, whose telomeres work in the same way. In future, people might be tested to see how long their telomeres - and their life expectancy - could be.
The groundbreaking research was published in the Proceedings of the National Academy of Sciences USA. (ANI)