Mammoth skeleton at the American Museum of Natural History: Photo by Mark Ryan.A new abundant source of viable DNA has been discovered in the preserved hair of woolly mammoths, those great ancient elephants that once roamed the Pleistocene landscape.

The new “life molecule” source opens a whole new world of study of not only mammoths, but a whole array of extinct mammalian species including musk ox, wooly rhinoceros, and even ancient man.

Prior to the discovery - the results of which appear in Science magazine - researchers regarded hair shafts as a poor source for mitochondrial DNA. Researchers used to glean the DNA by extracting it from the ground-up bone material or preserved muscle. Unfortunately, that DNA is susceptible to rapid breakdown soon after death due to bacteria contamination and exposure to the elements.

“DNA from hair is very clean because it has been encapsulated in keratin, a kind of plastic membrane that protects the hair and the DNA,” explained Thomas Gilbert, one of the study’s authors and a researcher at the University of Copenhagen in Denmark. The research team included scientists from Penn State, and an international consortium of scientists and museum curators.

The team’s process works this way: hair samples are first washed with a special concoction containing bleach that removes any contaminating bacteria that may be present on the strands. Next, enzymes are used to break down the protective proteins (e.g. keratin) that encase the hair, subsequently releasing the DNA from the long-dead hair cells. Two types of DNA can then be retrieved. Mitochondrial DNA that holds data about the species migration, and nuclear DNA that carries information about the evolutionary relationship between different species.

Hair strands were taken from nearly a dozen mammoths dug up across northern Siberia, and ranging in age from 12,000 to 50,000 years old. One of the specimens tested was from the very first recorded mammoth discovered in the permafrost in 1799. Known as Adams’ mammoth, it had spent two centuries stored at room temperature in the backroom of a Russian museum.

Scientists think the process may prove valuable using other keratin-based body parts such as horns, hooves, antlers and feathers. That would open up a whole new world of possibilities for extracting usable DNA from the loads of material stored in the backrooms of museums around the world, material that until now considered useless as DNA sources.

Researchers hope this new DNA source will help answer such questions as why the wooly mammoth and other Pleistocene animals went extinct, or unravel the complexities of relationships between species. But the new source could also aid present-day crime scene investigators.

“It is not only interesting in relation to the past, but also to the present in e.g. forensics,” said Eske Willerslev, an expert in ancient DNA at the University of Copenhagen. “But some development is needed yet for the method to be 100 per cent usable in that context. But it is only a question of time and refinement.”

Whatever the case, these new DNA sources open up a whole world of possibilities in the fields of paleontology and genetics.

"Think about all the extinct furred animals that are displayed on museums around the world,” Tom Gilbert mused. “There is a lot of work waiting for us."

LINKS

Science Daily story
Science News Online story
Story at Univ. of Copenhagen site
Eske Willerslev's site
More about DNA

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