Origin: A Genetic History of the Americas

Origin: A Genetic History of the Americas
by Jennifer Raff
Twelve (February 8, 2022), 369 pages
Kindle edition $14.99, Amazon hardcover $14.99

In Origin Jennifer Raff sets out to dispel some of the misconceptions about the origins of humans in the Americas and to describe some of the results of the most recent genetic research on the subject.

A central component of the study of humans in the Americas is the Clovis people, named for the town in New Mexico near which their arrowheads were found. They were believed to be in the Americas around eleven thousand years ago. Some old-school archaeologists and anthropologists insist that these were the earliest peoples in the Americas and that sites believed to be earlier are not to be trusted. Raff disagrees, and her irritation with this approach shows. She tells us that humans were in the Americas fourteen to fifteen thousand years ago by the most conservative estimates, and perhaps as much as thirty thousand years ago, depending on the evidence you accept.

Raff is a geneticist and her work along with that of her colleagues takes a much more nuanced view than that of some traditional archaeologists. Their work shows at least four distinct genetic groups who migrated to the Americas at different times.

The author also uses the latest research to debunk other preconceived notions. Disputing the long-held belief that there was a Bering land bridge over which people migrated from Siberia to the Americas, she shows how more recent research suggests that there was a land mass called Beringia in the region where people lived, hunted, fished, and had families for many centuries. It was only later that they moved on to the Americas. She makes the case that some could have made the trip by sea rather than by land.

Although a geneticist, Raff has the utmost respect for her archaeologist colleagues and spends a lot of time discussing the archaeological evidence. She visits one archaeological site, a cave in South America, to see the first-hand the work her colleagues were doing. She understands the criticality of preserving the integrity of such sites. She writes:

Take nothing but pictures. Leave nothing but footprints. Kill nothing but time. (And vandals, some of my father’s friends added, darkly—the gallows humor of long-suffering veterans of cave conservation.)

She discusses her work at a site in Alaska as a consulting geneticist, removing genetic material for study from ancient people whose remains were being moved to safer ground in advance of rising sea levels.

Raff describes in detail the methodology she and her colleagues use to extract ancient genetic material in order to prevent contamination. There are several layers and levels of safety and decontamination she must go through before starting work on a sample. It made me think of the decontamination scene in the movie version of The Andromeda Strain. Such precautions are well-justified, however. Another book I read describes how the first scientist who attempted to sequence a Neanderthal genome ended up with results that were mostly his own genes.

The author is adamant on one issue: respecting the wishes of Indigenous people. She firmly believes that scientists should not study the genes of the remains of Indigenous people without the consent of present-day descendants. While she describes incidents of cooperation between scientists and Native Americans, she also pointedly recounts those times when science did not respect the wishes of the people and engendered their mistrust.

If you are interested in the latest work on human migration to the Americas, Origin is a great place to start.