The moa bird bones, which were found in similar areas and dated from between six hundred to eight thousand years old, allowed researchers to study them at differing points of decay, and come up with a reasonable estimate of how fast the DNA in them was decaying.

What they found was that the DNA had a half-life of about 521 years.

This means that after about 521 years half the nuceotides in a sample will have broken down, after another 521 years, half of the remainder would have broken down, and so on.

According to a report in Nature, scientists estimate that every bond will have broken down over 6.8 million years even under ideal conditions (at about -5 degrees celsius), but it would only take 1.5 million years for DNA to become unreadable due to the remaining strands becoming too short.

Dinosaur bones are about 65 million years old.

“This confirms the widely held suspicion that claims of DNA from dinosaurs and ancient insects trapped in amber are incorrect,” Simon Ho, a computational evolutionary biologist at the University of Sydney in Australia, told Nature.

You can read the full story on Nature.com.