Scientists discover genetic link between Native Americans and Pacific Islanders

A number of indigenous people in the Amazon rainforest may in part be descended from the peoples of the Pacific, the researchers say.

It remains a mystery as to when and how this genetic signature of a group from Australasia in the Pacific they call “Population Y” made its way to the Amazon, the scientists added.

Most genetic studies have suggested that all Native Americans analyzed To this day, many or all of their ancestors can be traced back to a single common origin – a population of Eurasia who probably migrated to the Americas over 15,000 years ago, back when the lower sea level is exposed the Bering Land Bridge known as Beringia which connected the continents. Some Native Americans of North America and the Arctic can also trace other parts of their ancestry to more recent waves of migration.

However, a number of previous studies of skull shapes have suggested that two distinct groups entered the Americas. While an Asian type is similar to the vast majority of modern native american, an earlier type seen on skeletons in Brazil and elsewhere looked like modern people from Australasia – a region that includes Australia, New Zealand, New Guinea, and neighboring Pacific islands – and even some African groups . [In Photos: Human Skeleton Sheds Light on First Americans]

To shed light on this mystery, scientists analyzed the DNA of 30 Native American groups from Central and South America and 197 non-American populations sampled around the world.

Researchers have found that some Native American groups from the Amazon forest – also known as the Amazon – derive a fraction of their ancestry from a population that is more closely related to the Onge of the Andaman Islands in the Bay of Bengal, New Guineans, Papuans and indigenous Australians than it does it is not for Eurasians or the indigenous people of today. Americans.

“This finding really surprised us,” said lead author of the study Pontus Skoglund, population geneticist at Harvard Medical School in Boston. “Most genetic studies to date have essentially revealed that all North Americans and South Americans come from a single ancestral source population. That’s not what we found – we found a more complicated scenario. . “

The current Native American populations of North and Central America appear to lack this genetic signature. Investigators suggest that a group they call “Population Y” – named Ypykuéra, which means “ancestor” in the family of Tupi languages ​​spoken in Brazil – passed on this Australasian genetic signature to the Amazonians. Population Y had already genetically mixed with a lineage related to Native Americans by the time they reached the Amazon.

It is still unclear when and how population Y reached South America. “We can’t say much about the history of the creation of this genetic link,” Skoglund told Live Science. “This discovery only raises other questions that we must answer about American history.”

Yet researchers don’t believe this genetic signature arrived by boat in the past few thousand years. “We believe the mixing happened earlier, potentially among the early colonizers of the Americas,” Skoglund said. “They probably came from Beringia.”

This discovery is one of many recent genetic surprises suggesting links between the Amazon and the Pacific. In 2013, Brazilian scientists unexpectedly discovered Polynesian DNA in the bones of the Botocudo, now extinct Amerindian hunter-gatherers who once lived in the interior of Brazil. However, Skoglund noted that the genetic signature of Amazonians analyzed by his team differed from that seen in Botocudo.

Researchers suggest analyzing DNA from ancient remains from across America to help solve these mysteries. They detailed their findings online today (July 21) in the journal Nature.

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