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View Full Version : Ancient DNA confirms Native Americans’ deep roots in North and South America



bicicleur
09-11-18, 09:40
https://www.sciencemag.org/news/2018/11/ancient-dna-confirms-native-americans-deep-roots-north-and-south-america?fbclid=IwAR0Jh-eTzZfz4FBXyMQxpVyCynaX4KdJ675eafgMd8hx3ux4YGp9QgoP cGQ

For decades, scientists could describe the peopling of the Americas only in broad strokes, leaving plenty of mysteries about when and how people spread across the continents. Now, state-of-the-art ancient DNA methods, applied to scores of new samples from around the Americas, are filling in the picture. Two independent studies, published in Cell and online in Science, find that ancient populations expanded rapidly across the Americas about 13,000 years ago. They also emphasize that the story continued in the thousands of years since, revealing previously undocumented, large-scale movements between North and South America.

The data include 64 newly sequenced ancient DNA samples from Alaska to Patagonia, spanning more than 10,000 years of genetic history. "The numbers [of samples] are just extraordinary," says Ben Potter, an archaeologist at the University of Alaska in Fairbanks. Prior to these studies, only six genomes older than 6000 years from the Americas had been sequenced. As a result, says Jennifer Raff, an anthropological geneticist at the University of Kansas in Lawrence, "The [genetic] models that we've been using to explain the peopling of the Americas have always been oversimplified."

Eske Willerslev, an evolutionary geneticist at the University of Copenhagen who led the Science team, worked closely with the Fallon Paiute-Shoshone Tribe in Nevada to gain access to some of the new samples. The tribe had been fighting to repatriate 10,700-year-old remains found in Nevada's Spirit Cave and had resisted destructive genetic testing. But when Willerslev visited the tribe in person and vowed to do the work only with their permission, the tribe agreed, hoping the result would bolster their case for repatriation.

bicicleur
09-11-18, 09:42
and another study :

How the people of the Andes evolved to live in high altitudes

https://www.sciencemag.org/news/2018/11/how-people-andes-evolved-live-high-altitudes?fbclid=IwAR2k6WE-Oka6Ysl4y7fntjABSQfT4xexwS0NZnR5EsvnGAjFZxNsB1IvQp 8

Scarce oxygen, cold temperatures, and intense ultraviolet radiation make the Andes a tough place to live. How did humans adapt to such heights? A new study of ancient and modern DNA suggests in some South American highlanders, the answer includes changes to their heart muscles. The same study found that ancient highlanders adapted to digest starch more easily as they came to rely on potatoes for food, and that they most likely split from their lowland brethren some 8750 years ago. But those conclusions have been questioned by scientists who say the comparison population is simply too distant to reveal anything specific about highland life.

To find out how ancient Andeans adapted to living at more than 2500 meters, John Lindo, a population geneticist at Emory University in Atlanta, sequenced seven genomes from people who lived near Lake Titicaca in the Peruvian Andes from 6800 years ago to about 1800 years ago. The team then compared those genomes to genetic data from two modern populations: the high-living Aymara of Bolivia, and the Huilliche-Pehuenche, who live on the lowland coast of southern Chile.

Another high-dwelling folk—the people of the Tibetan plateau—have genetic variations that reduce hemoglobin levels in their blood and make their bodies extremely efficient at using oxygen. So Lindo and his colleagues scanned the ancient South American genomes for signs of similar adaptations. They didn’t find what they were looking for, but they did see signs of selection on a gene called DST, related to cardiovascular health and heart muscle development, they report today in Science Advances. That, says Mark Aldenderfer, an archaeologist at the University of California (UC), Merced, and a co-author of the new study, “suggests a very different process by which ancient Andean people adapted to high elevation life.”

Pajonk
04-04-19, 16:14
Hm, pretty interesting