Soil Yields Ancient DNA Left From Extinct Life

Ancient plant and animal DNA found in undisturbed soil sediment can unlock secrets about life hundreds of thousands of years ago, researchers reported Thursday in the journal Science.

Scientists analyzing soil from Siberian permafrost and from caves in New Zealand said they found evidence of DNA from animals that died out thousands of years ago, and from plants that lived about 400,000 years ago.

Eske Willerslev of the University of Copenhagen, a co-author of the study, said scientists found that soil fragments the size of a sugar cube can contain large amounts of DNA from ancient life forms.

The scientists identified DNA from 19 categories of plants and eight kinds of animals, including the extinct mammoth and steppe bison. The animal DNA was thought to be as old as 30,000 years.

Co-author Alan Cooper of Oxford University said that the study shows DNA can be preserved for long periods and could free researchers “from the shackles of needing fossils to be able to look into the past.”

For instance, the plant DNA from Siberia suggests that tundra was once an area rich in plants, capable of supporting large herds of mammoths and other big animals.

But about 11,000 years ago, the once plentiful grasses began to disappear, perhaps helping to cause the extinction of some of the large plant eaters that once roamed parts of Siberia and Alaska.