Clues in DNA reveal how long you'll live -
and they can be read when you're a baby
Written into DNA as a
baby - and can only be shortened, not made longer
Can be tested in
finches from just 25 days old
Tests could be
available for humans soon
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 protect chromosomes from wear and
tear
Scientists have found
a way to predict how long someone will live – by measuring their genes as a
baby.
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.
Put simply, the longer
your telomeres, the longer you will live -dependent, of course, on not
dying accidentally, from disease or from lifestyle factors.
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.
In the future, tests
may allow people to know their expected lifespan from a very early age - if
they want to.
Professor Pat
Monaghan, who led the Glasgow University study, said: ‘The results of this
research show that what happens in our bodies in early life is very important.
‘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.
If you were to test
this, I don’t think anyone would want to know – it would just make you
miserable. But it must be remembered that how you live has a big effect. This
isn’t quite a case of nature overtaking nurture.’
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.
Professor Monaghan
said: ‘These birds were dying of natural causes. There were no predators, no
diseases and no accidental deaths. This was showing their capacity for long
life.’
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.
Telomeres are
important because they stop DNA from unravelling – but they begin shortening
from the moment we are conceived.
The longer they are,
the better for an individual because when they get too short, they stop
working.
DNA is then no longer
protected and errors begin to creep in when cells divide. When this happens –
usually in middle age – the skin begins to sag and the immune system
becomes less efficient. Faulty cells also lead to a growing risk of conditions
such as diabetes and heart disease.
The university’s
institute of biodiversity, animal health and comparative medicine has published
its groundbreaking research in the Proceedings of the National Academy of
Sciences USA.
In the next stage of
their research, the Glasgow scientists will look at what causes telomeres to
shorten – including inherited and environmental factors – to make it
possible to predict life expectancy more accurately.
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