The 'origin' of the controversial scientific discovery of the first Americans

The scientific understanding of the habitability of the Americas is not as disturbing as it once was in the Western Hemisphere. But the remains of skeletons, cultural artifacts such as stone tools and an increasing number of microscopic ancient DNA fragments have sparked heated debates over which story best explains the origin. inherent in the Americas. Additional conflict stems from a tragic scientific legacy of ignoring and exploiting Indigenous groups with lineage ancestry.

Anthropologist and geneticist Jennifer Raff asked her to take on the status of this tumultuous and fascinating field of study in Origins: The Genetic History of the Americas.

Raff wanted to tell the most accurate, if incomplete, story of how humans settled the Americas by integrating the study of ancient and modern DNA with archaeological finds. She refers to people who inhabited the Western Hemisphere before the arrival of the Europeans as First People, a term favored by some of her Indigenous colleagues.

Another view is that humans arrived in the Americas much earlier.

Most researchers think that the ancestors of the First Humans lived in Siberia and East Asia 20,000 years or more ago during the Ice Age, Raff explained. One consensus view is that these groups eventually crossed a currently submerged landmass - the Bering Land Bridge - connecting Northeast Asia and North America. Analyzes of ancient human DNA indicate that these migrations gave rise to populations living south of an ice sheet that ran across northern North America between 80,000 and 11,000 years ago. But many things remain unexplained.

Raff delves into several competing models of how, when, and where the first humans entered the Americas. One approach holds that the Ice Age Siberians, known from archaeological finds, arrived in North America 16,000 to 14,000 years ago and, within a few millennia, journeyed south across the continent. through a gap in the melting ice sheet. Those settlers probably founded the Clovis culture, known for its distinctive rock spots (SN: 1/15/22, p. 22).

Another view is that humans arrived in the Americas much earlier, 30,000 years ago or more. A handful of researchers in this camp suggest that settlers may have even reached what is now southern California 130,000 years ago (SN: 5/27/17, p. 7).

But archaeological and genetic evidence fits the third pattern best, Raff writes. In this scenario, the First Humans reached the Americas as early as 18,000 years ago and perhaps more than 20,000 years ago. These people - including groups that were not precursors to the Clovis people - probably traveled by boat or canoe along the west coast of North America, arriving in South America no later than about 14,000 years ago (SN: 26/ 12/15, page 10).

Raff presents the scientific arguments for these settlement scenarios in clear, non-technical language. But her story resurfaces when she describes how geneticists, with some admirable exceptions, have treated Indigenous groups as followers or donors. passive DNA donation.

One example involves a skeleton about 9,000 years old found in Washington state in 1996, known as the Kennewick Man or Ancient Man. That discovery has sparked a legal battle between scientists interested in studying the man's remains and local tribes intent on reburiing their ancestors. The scientists won. Years later, geneticists who consulted with one tribe in the dispute drafted an agreement to take a sample of the tribe's DNA to compare with the Ancients - and prove a link. ancestors - before his bones were tampered with by this tribe (SN: 7/25/15 , p. 6 ).

Many Native American groups, especially in North America, hold bad memories of genetic researchers who misled them about research goals or never met with them to discuss DNA results contradict the tribe's oral history, Raff writes. As a result, indigenous communities today often refuse to participate in genetic studies. She argues that only researchers' commitment to collaborating with those groups can resolve this impasse, as belatedly happened with the Ancient One.

Raff also provides a glimpse into how she came to study ancient DNA. A lifelong love of caving, which began as a kid in the explorers club, instilled in Raff a respect for thorough preparation and intense focus in the moment. this. Those traits proved necessary to conduct many of the precise lab procedures she outlined to get DNA out of a bone sample.

After mentioning that several large, well-funded laboratories dominated ancient DNA research, Raff had not yet explored the impact of concentrating such resources on the study of ancient human migrations. Grand. But her book offers a balanced look at what is known about the First Men and how scientists can collaborate with their modern-day descendants.