New Scientist
Image: M. Allentoft
We are used to radioactive substances having a half-life, but DNA? Now a study of bones from extinct birds suggests the double helix too has a measurable half-life – and that we have underestimated its ability to survive in the fossil record.
“DNA degrades at a certain rate, and it therefore makes sense to talk about a half-life,” says Morten Allentoft at Copenhagen University, Denmark, who together with Mike Bunce at Murdoch University in Perth, Australia, and colleagues, extracted DNA from the leg bones of 158 extinct flightless birds called moas.
Part of the reason a DNA half-life has been so elusive is that it is hard to find a large enough cache of samples that have been exposed to similar conditions. The moa bones were all between 600 and 8000 years old, and came from a 5-kilometre-wide area of New Zealand’s South Island, key factors for helping identify a regular pattern of decay.
With an estimated burial temperature of 13 ºC, the DNA’s half-life was 521 years – almost 400 times longer than expected from lab experiments at similar temperatures, says Allentoft. Read more on newscientist.com…
