Give Now  »

Noon Edition

How Big Was the Founding Population of Native Americans?

An image taken at the Bering Land Bridge National Park. This park in the United States houses one of the last remaining remnants of the Bering Land Bridge described in this artifice. (Bering Land Bridge National Park, Flickr)

You might already know that the first humans came to the Americas from Siberia across a land bridge from Siberia to Alaska during the last ice age. They came no earlier than about twenty-three thousand years ago.

The first humans spread across the North and South American continents to create a population of about forty million people. That much is well known, but what I've always wondered about was how large the original population was that came across the land bridge.

Genetic Variability

In 2018, a team of American and Brazilian researchers published a study which may provide an answer. I assumed when I heard about this study that they could maybe tell from the size of campsites across the land bridge.

The researchers found a much better way. They compared the genomes of modern Asian groups and modern Native American groups and looked for an ancient population size that explains current genetic variability. The patterns they found could tell them how narrow the genetic bottleneck was for the original inhabitants of the Americas.

From Siberia To China, From Central America to South America

They took genetic samples from ten modern Asian groups, from Siberia to China, and ten different groups of Native Americans from Central and South America. The scientists also studied nine carefully chosen inactive segments of the genome.

The researchers found that the genetic bottleneck was severe and the founding population of all native peoples of the Americas was just a few hundred people, most probably about two hundred and fifty. From this small beginning, Native Americans recovered their genetic diversity through random genetic mutations that happened afterwards.

Thank you to Rolando Gonzalez-Jose of the Patagonian National Center, National Council of Scientific and Technical Research, Puerto Madryn, Argentina for reviewing this episode's script.

Sources And Further Reading:

Support For Indiana Public Media Comes From

About A Moment of Science