Results from a DNA study of a young boy's skeletal remains believed to have died 24,000 years old has shed new light on the origins of the first people to colonize America much before Christopher Columbus.
Maanasa Raghavan from the Natural History Museum of Denmark's Centre for Geo Genetics has shown that nearly 30% of modern Native American's ancestry came from this youngster's gene pool, suggesting that the first Americans came directly from Siberia.
Speaking to TOI from Toronto where she now lives with her parents - both of whom are accountants, Maanasa said the study proves that Native Americans ancestors migrated to the Americas from Siberia and not directly from Europe as some have recently suggested.
It is also now clear that the boy had close genetic ties to today's Native Americans and some western Eurasians, specifically some groups living in central Asia, South Asia, and Europe.
The researchers said "We think these Ice-Age people were quite mobile and capable of maintaining a far-reaching gene pool that extended from central Siberia all the way west to central Europe."
Kelly Graf from Texas A&M University "our results indicate Native American ancestors could have been in Beringia - extreme northeastern Russia and Alaska - any time after 24,000 years ago and therefore could have colonized Alaska and the Americas much earlier than 14,500 years ago, the age suggested by the archaeological record".
The team also finds evidence that this genetic affinity between MA-1 and Native Americans is mediated by a gene flow event from MA-1 into the first Americans, which can explain between 14-38% of the ancestry of modern Native Americans, with the remainder of the ancestry being derived from East Asians.
The scientists said "Supported by numerous reasons against these signatures being caused by contamination from modern DNA sources or from post-Columbian admixture (post 1492 AD), the study concludes that two distinct Old World populations led to the formation of the First American gene pool: one related to modern-day East Asians, and the other a Siberian Upper Palaeolithic population related to modern-day western Eurasians".
"The result came as a complete surprise to us. Who would have thought that present-day Native Americans, who we learned in school derive from East Asians, share recent evolutionary history with contemporary western Eurasians? Even more intriguingly, this happened by gene flow from an ancient population that is so far represented only by the MA-1 individual living some 24,000 years ago," says professor Eske Willerslev from the Centre for GeoGenetics who led the study.
Dr Pontus Skoglund from Uppsala University, and one of the lead authors of the study, explains, "Most scientists have believed that Native American lineages go back about 14,000 years ago, when the first people crossed Beringia into the New World. Our results provide direct evidence that some of the ancestry that characterizes Native Americans is at least 10,000 years older than that, and was already present in Siberia before the last Ice Age".
The international team of researchers that Maanasa was part of - researchers from Sweden, Russia, UK, University of Chicago and University of California-Berkeley traveled to the Hermitage State Museum in St Petersburg, Russia, where the remains are now housed to collect samples for ancient DNA.
The skeleton was first discovered in the late 1920s near the village of Malta in south-central Siberia, and since then it has been referred to as "the Malta child" (MA-1 genome) because until this DNA study the biological sex of the skeleton was unknown.
Maanasa who left India at the age of 12 and is now a Canadian citizen says the DNA work performed on the boy is the oldest complete genome of a human sequenced so far.
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