DNA From Frozen Human Hair Helps Determine How Native Americans Looked

A single human hair has provided scientists with information about Native American migration thousands of years ago.

Using DNA from a 4,000-year-old frozen human hair from Greenland, researchers have uncovered a wealth of information on the individual's origin and appearance. 

He was a man with brown eyes, thick-dark hair, non-white skin, dry ear-wax and A-positive blood-group. He had a susceptibility to baldness and belonged to the Saqqaq culture, the first group of people known to have settled in Greenland. 

Griffith University's ancient-DNA expert Professor David Lambert said the preserved human hair was helping to unveil the origins of the Saqqaqs, which was hotly debated until now. 

"The DNA from the frozen hair indicates the Saqqaq individual was closely related to people from Eastern Siberia," Professor Lambert said. 

"This came as a surprise as previous theories proposed that Saqqaqs' ancestors were migrants from neighbouring Native American populations. 

"It now appears there was a substantial migration from Eastern Siberia across the Bering Strait and over North America to Greenland 5,400 years ago. 

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"The ancestors of today's Native Americans had made their journey across the strait into the New World a lot earlier, perhaps about 20,000 years ago." 

Professor Lambert's paper on evolutionary biology was published in the prestigious journal Nature and commented on the work of the scientists from the University of Copenhagen, who sequenced the DNA preserved in the frozen hair and compared it with the DNA of modern humans. 

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Professor Lambert said ancient-DNA studies were technically challenging, but advances in the molecular technologies and the growing human genome databases had enabled this first genome sequence analysis of an ancient human. 

"Previous studies on ancient bone or muscle tissues have shown they tend to be contaminated by modern DNA, but human hair is typically well-preserved with little contamination from fungi or bacteria," he said. 

"We have an increasingly powerful forensic tool with which to 'reconstruct' extinct humans and the demographics of population movements on a scale not previously seen. 

"The next technical challenge will be to try to sequence ancient DNA from human remains in temperate and hot environments. The rate of degradation of ancient DNA increases exponentially with temperature and it remains to be seen whether genomic studies on these regions will be informative." 



Source-Medindia
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