Bone DNA reveals humanity’s trek into South America
Skeletons from Peru caves plot course for a single migration to the continent.
Photo Christian Kapteyn/Robert Harding DNA from humans who lived in the Andes 9,000 years ago gives clues to how South America was peopled.
Summary from Bone DNA reveals humanity’s trek into South America
New findings from recently DNA recovered of five individuals from high elevation in the Peruvian Andes suggests that South America may have been settled in a single wave of migration not much later than their ancestors migration through Siberia into the Western Hemisphere. There have been arguments for at least two migrations based on skull morphology, suggesting that those peoples with long, narrow skulls of about 5,000 years ago came before the rounder headed peoples of ancestors of today’s indigenous peoples.
The individuals tested came from the Lauricocha region in Peru, from a site originally discovered by Peruvian archaeologist Augusto Cardich in the 1950’s and 60’s. A current team from the University of California, Santa Cruz lead by Lars Fehren-Schmitz, a biological anthropologist, relooked at the remains with current dating techniques and DNA extraction.
Their work, presented by Fehren-Schmitz at the SAA meeting, paints a complicated picture of Lauricocha. Two of its residents, a woman and a 2-year-old child, died nearly 9,000 years ago. The third, a man, perished around 2,500 years later and another man died about 2,300 years later still. The fifth specimen was not dated because of its condition. Only the woman’s skull had a long, narrow shape, which is known as dolichocephaly.
The mitochondria DNA findings show that all five were descendant from the material lineage common among most indiengous people of North and South America. The Male Y lineage arose in the Bering Strait region about 17,000 years ago.
Other archaeologist say the data is not conclusive and more individuals in more regions need to be researched to rule out any other waves of migration to South America.
Ancient South American genomes may also show how humans adapted to the New World. In a separate study, Fehren-Schmitz and his colleagues looked at a gene variant that protects against altitude sickness. Between around 8,500 and 600 years ago, the presence of the variant increased markedly among the Andeans.
Fehren-Schmitz says that the finding is merely suggestive of local adaptation. But with full, ancient genomes in hand, researchers will be able to look more thoroughly for signs of adaptation to high altitude, says Bolnick. With that question in mind, her team is sequencing DNA from remains of mountain residents of Argentina.