Ancient DNA Unlocks Secrets of Ice Age Tribes in the Americas

Skulls and other human remains from P.W. Lund's Collection from Lagoa Santa, Brazil. Kept in the Natural History Museum of Denmark. (Image: Natural History Museum of Denmark)
Skulls and other human remains from P.W. Lund's Collection from Lagoa Santa, Brazil. Kept in the Natural History Museum of Denmark. (Image: Natural History Museum of Denmark)

Scientists have sequenced 15 ancient genomes spanning from Alaska to Patagonia and were able to track the movements of the first humans as they spread across the Americas at “astonishing” speed during the last Ice Age, and also how they interacted with each other in the following millennia.

The results have been published in the journal Science as part of a wide-ranging international study, led by the University of Cambridge, which genetically analysed the DNA of a series of well-known and controversial ancient remains across North and South America.

The research also discovered clues of a puzzling Australasian genetic signal in the 10,400-year-old Lagoa Santa remains from Brazil revealing a previously unknown group of early South Americans — but the Australasian link left no genetic trace in North America.

Professor Eske Willerslev with Donna and Joey, two members of the Fallon Paiute-Shoshone tribe. (Image: via University of Cambridge)

Professor Eske Willerslev with Donna and Joey, two members of the Fallon Paiute-Shoshone tribe. (Image: via University of Cambridge)

Additionally, a legal battle over a 10,600-year-old ancient skeleton — called the “Spirit Cave Mummy” — has ended after advanced DNA sequencing found it was related to a Native American tribe. The researchers were able to dismiss a longstanding theory that a group called Paleoamericans existed in North America before Native Americans.

The Paleoamerican hypothesis was first proposed in the 19th century, but this new study disproves that theory. Professor Eske Willeslev, who holds positions at the Universities of Cambridge and Copenhagen, and led the study, said:

The scientific and cultural significance of the Spirit Cave remains, which were found in 1940 in a small rocky alcove in the Great Basin Desert, was not properly understood for 50 years. The preserved remains of the man in his forties were initially believed to be between 1,500 and 2,000 years old, but during the 1990s, new textile and hair testing dated the skeleton at 10,600 years old.

The Fallon Paiute-Shoshone Tribe, a group of Native Americans based in Nevada near Spirit Cave, claimed cultural affiliation with the skeleton and requested immediate repatriation of the remains.

Sumidouro Lake in Lagoa Santa, Brazil. The formation to the right of the picture contains the caves where the skulls are found. (Credit: Natural History Museum of Denmark)

Sumidouro Lake in Lagoa Santa, Brazil. The formation to the right of the picture contains the caves where the skulls are found. (Image: Natural History Museum of Denmark)

Their request was refused and the tribe sued the U.S. government, a lawsuit that pitted tribal leaders against anthropologists, who argued the remains provided invaluable insights into North America’s earliest inhabitants and should continue to be displayed in a museum.

The deadlock continued for 20 years until the tribe agreed that Professor Willeslev could carry out genome sequencing on DNA extracted from the Spirit Cave for the first time. Willeslev said:

The team extracted DNA from the inside of the skull proving that the skeleton was an ancestor of present-day Native Americans. Spirit Cave was returned to the tribe in 2016 and there was a private reburial ceremony earlier this year. The tribe was kept informed throughout the 2-year project and two members visited the lab in Copenhagen to meet the scientists and they were present when all of the DNA sampling was taken.

A skull from P.W. Lund's Collection from Lagoa Santa, Brazil. Kept in the Natural History Museum of Denmark. (Credit: Natural History Museum of Denmark)

A skull from P.W. Lund’s Collection from Lagoa Santa, Brazil. Kept in the Natural History Museum of Denmark. (Image: Natural History Museum of Denmark)

The genome of the Spirit Cave skeleton has wider significance because it not only settled the legal and cultural dispute between the tribe and the government, it also helped reveal how ancient humans moved and settled across the Americas. The scientists were able to track the movement of populations from Alaska to as far south as Patagonia. They often separated from each other and took their chances traveling in small pockets of isolated groups.

Dr. David Meltzer, from the Department of Anthropology, Southern Methodist University, Dallas, said:

The study also revealed surprising traces of Australasian ancestry in ancient South American Native Americans, but no Australasian genetic link was found in North American Native Americans. Dr. Victor Moreno-Mayar, from the Centre for GeoGenetics, University of Copenhagen and first author of the study, said:

Dr. Peter de Barros Damgaard, from the Centre for GeoGenetics, University of Copenhagen, explained why scientists remain puzzled but optimistic about the Australasian ancestry signal in South America. He explained:

The population history during the millennia that followed initial settlement was far more complex than previously thought. The peopling of the Americas had been simplified as a series of north to south population splits with little to no interaction between groups after their establishment.

The new genomic analysis presented in the study has shown that around 8,000 years ago, Native Americans were on the move again, but this time from Mesoamerica into both North and South America.

Researchers found traces of this movement in the genomes of all present-day indigenous populations in South America for which genomic data is available to date. Dr. Moreno-Mayar added:

Provided by: University of Cambridge [Note: Materials may be edited for content and length.]

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