DNA could hold key to origins of life
A 425-million-year-old micro organism found in a salt in a remote part of the USA is 4,000 times older than the earliest DNA found so far.
Before this discovery, the oldest genetic material was taken from the remains of prehistoric mammals preserved in ice.
Professor Bill Grant said his discovery, in Michigan, opened up new possibilities for investigating the origins of life on earth.
He said it would provide a powerful tool for space missions seeking signs of extra-terrestrial life.
The finding - published today in the science journal Nature - will further boost the reputation of genetics research at the University of Leicester, where Professor Sir Alec Jeffreys discovered genetic fingerprinting.
Fossils of micro-organisms from 3.5 billion years ago are the earliest evidence of life on earth, but are too crude to tell us much about the life-forms.
DNA, the genetic code of plants and animals, can reveal a vast amount of information about them but, until now, it was thought only able to survive for tens of thousands of years.
Professor Grant and his team found tiny fragments of DNA from a complex range of micro-organisms - none of which exist today - in the salt deposits from 425 million years ago.
"The DNA is the remains of micro-organisms that were trapped in the salt when seas dried up. These findings open up a new avenue of research. We can now use salt deposits to research life dating back millions and even billions of years."
Professor Grant said researchers could modify the technique to show how much cells had changed since the first known life-forms appeared on earth and could be used to look for life on other planets.
The University of Leicester is leading the search for life on Mars.
Professor George Fraser, of the University's Space Research Centre, said: "It is fantastically encouraging that DNA can be preserved for periods of 425 million years. It means that, if life had existed on Mars, even hundreds of millions of years ago, we should be able to find it."
[pic courtesy Leicester Mercury]
Last updated: 23 May 2002 13:55
Created by: Rachel Tunstall
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