Impossible! Scientists retrieve ancient Viking DNA

BEIJING, May 30 (Xinhuanet) -- A team of scientists may have done what was once thought impossible by retrieving strands of ancient, authentic 1,000-year-old DNA from 10 Viking skeletons

Jorgen Dissing of the University of Copenhagen and colleagues say they retrieved the genetic material from the freshly sampled teeth of skeletons dating back to around A.D. 1000 and found at a non-Christian burial site called Galgedil on the Danish island of Funen.

Wearing protective suits, the researchers removed the teeth from the jaw at the moment the skeletons were unearthed, where they had lain untouched for 1,000 years. Subsequent laboratory procedures were carefully controlled to avoid contamination with modern human DNA.

In the past few years, several studies have shown that it is possible to recover authentic ancient human DNA if strict measures are taken to avoid contamination.

"The present work provides further evidence that retrieval of authentic DNA from ancient humans is indeed a possible undertaking provided adequate precautions are observed," the authors wrote in this week's issue of the journal PLoS ONE.

Although "Viking" often refers to pirates and robbers at sea, recent research has indicated that the Vikings were also traders to the fishmongers of Europe. Dissing and his colleagues are interested in family relationships among populations of Vikings and genetic variation among them. The team has also obtained DNA sequence results on other ancient humans ─ from an early Christian cemetery dating from A.D. 1000 to A.D 1250, two Roman Iron Age settlements from A.D. 0 to A.D. 400 and Greenland Inuit from about A.D. 1450.

Severe problems connected with the retrieval and analysis of DNA from ancient organisms (such as the scarcity of intact molecules) are further aggravated in the case of ancient humans. This is because of the great risk of contamination with abundant DNA from modern humans.

However, analysis of the Viking DNA showed no evidence of contamination with extraneous DNA, Dissing said, and typing of the DNA gave reproducible results and showed that these individuals were just as diverse as contemporary humans.

(Agencies)