Fossil DNA expiry date found
In the ultimate mythbuster, Australian scientists have shown that extracting dinosaur DNA from fossils like they did in Steven Spielberg's epic film Jurassic Park is an ''extreme improbability''.
A study by ancient DNA researchers at Western Australia's Murdoch University has found the hereditary material cannot survive more than 6.8 million years. Most dinosaurs died out 65 million years ago.
''We've been permanently plagued by this Jurassic Park myth that's been kicking around since the early '90s,'' the study's lead researcher, Mike Bunce, said.
While scientific papers claiming 135 million-year-old insect DNA had been extracted from amber had been largely debunked due to the samples being contaminated with human genetic material, the belief that DNA can be extracted from dinosaur fossils persisted, he said.
''The myth is still out there. Even other scientists ask whether it is possible.''
To establish how long bone DNA could survive, Dr Bunce and fellow researcher Morten Allentoft carbon-dated bones from 158 moa, the extinct New Zealand bird.
They found that the total amount of DNA from the bones halved after about 521 years when stored at 13.1 degrees.
''We've come up with a rate from this site and then we can extrapolate that [to other sites] based on the variation in temperature, like what would happen in a frozen environment or a slightly warmer environment,'' said Dr Bunce, whose findings are published in the Proceedings of the Royal Society B.
At minus five degrees the team estimated the last fragments of DNA in a bone would disappear after 6.8 million years.
''But it's probably at about one million years in frozen conditions that you can extract a meaningful bit of DNA and do something with it,'' he said.
Other conditions, such as how long a bone had been stored and how deep it had been deposited, also affected the period of time DNA survived, he said.
Sydney Morning Herald