7 December 2015

Third Sunday of Advent: When a genome alters Native American history


Today’s advent calendar researcher has restructured the first American family tree by studying the genome of a boy who lived in Siberia 24,000 years ago. Paleogeneticist Eske Willerslev is a frequent publisher of research that forces us to revise what we think we already know about history.

24,000 years ago, a four-year-old boy died and was buried in an area known as Mal’ta, near Lake Baikal, Siberia. In 2009, Professor Eske Willerslev of the Center for Geogenetics at the Natural History Museum of Denmark visited the site to where the body had been moved along with colleagues from the Hermitage State Museum in Saint Petersburg. Four years later, the boy’s genome was mapped – with results that surprised the world.

Studies of the 24,000 year-old skeleton showed that present day first Americans are of close genetic relation to the four-year-old boy from Siberia. Until now, we thought that modern day indigenous peoples were genetically linked to East Asians. The other interesting thing garnered from the ancient skeleton was that the boy is also genetically related to modern day Europeans.

 “The results demonstrated that people who had once lived in Central Asia contributed genetic material to both modern day Europeans and Native Americans. As such, the prehistory of the indigenous people of the Americas must be rewritten. We all thought that they came from people closely related to the Chinese and other Asians, but one-third of the indigenous genome comes from a group of people who have close genetic ties with Northern Europeans,” explains Willerslev.

Results confirmed by 12,000-year-old boy

The 24,000-year-old Siberian boy’s skeleton is seen as the missing piece of a puzzle surrounding the history of Native Americans. And one year later, Eske Willerslev headed an international team of researchers to present yet another piece of the puzzle.
The skeleton of a boy, the “Clovis boy”, that died 12,600 years ago has provided evidence of an extremely close genetic relation with modern day Native Americans.

 “It is estimated that 80 percent of all Native Americans on the two American continents are direct descendants of the Clovis boy’s family. The remaining 20 percent are more closely related to the Clovis family than they are to any other group of people on earth,” says Eske Willerslev in relation to the results published of the 12,000-year-old skeleton.

Like modern day Native Americans, the Clovis boy shared one-third of his genes with the 4-year-old Siberian boy who lived 24,000 years ago, so the researchers reckon that America was indeed populated by people from Siberia.

Curiosity is key

Curiosity is what brought the 24,000 year-old skeleton in St. Petersburg to the researchers’ attention:

 “We were studying the bones out of shear curiosity. We had absolutely no idea of what they would present,” explains Willerslev. “This result shows us that we must investigate all possibilities, because what we once thought to be true, well, it proved not to be so in the end.”

For Willerslev, it is the most exciting research that he has ever conducted. And as he says, ”I’ve tried a bit of everything.” Much of his interest these days is devoted to the evolution of disease. Along with colleagues, he is attempting to coax bacteria from old skeletons so as to study the evolution of diseases.