How did the first humans get to America?

A Neanderthal, the species that homo sapiens would eventually drive to extinction | Image: Wikipedia We all know that the first humans on our planet lived in Africa. It’s simple enough to explain how they got to the Middle East, then Europe, then Asia, but how on Earth did they get all the way to America?

A major new genetic study has given massive support to the theory that the first Americans got to the continent by traveling from Siberia, across the Bering Strait on a land bridge that is now covered in water. There were two separate influxes – one around 30,00 years ago, and one after the end of the last Ice Age, 12,000 years ago.

So how is it possible to tell which direction humans migrated tens of thousands of years ago? The new research (published in the jornal Science) collected information on ‘genetic markers’ from about 1000 people from all over the world. By comparing who has which markers, it is possible to tell which populations are most closely related to each other. (Click here for an extensive interactive guide detailing human migration)

Map of human migration | Image: National Geographic

Other interesting finds from the research include the fact that the further you go from Africa, the less diverse human genetic code becomes. This is because only a relatively small number of pioneering humans actually came out of Africa, and so all the rest of the world is descended from only a small pool of genetic variation.

And one fascinating fact that should forever put an end to racism: over 90% of all genetic variation in humans occurs in populations themselves, rather than between different populations and races. So there may be more genetic difference between two white Americans than between a Hispanic and an Aborigine. Now that’s something to think about.

If you think this research is interesting, why not join the Genographic Project, a new genetic survey aiming to be the biggest of its kind ever undertaken. It’s co-sponsored by IBM and National Geographic. Please note that the Genographic Project is completely unrelated to the research detailed above.


8 Responses

  1. Hi Richard, I thought that National Geographic Genome study had close to 100,000 samples, not 1,000 as you wrote. Was this a typo?

  2. thewordofme: Sorry if I caused any misunderstanding – the Genographic Project is completely unrelated to the research I wrote about in this post. I just thought that people interested in the research I wrote about (published in the jornal ‘Science’) might be interested in the NG Genographic project too, so I may as well promote it.

    I’ve edited the post to clarify this issue. Thanks for telling me! 🙂

  3. yeah, this info really helped.

  4. Something here does not add up. It would have been quite impossible for Asians to reach the American heartland ca. 30,000 years ago because of the massive glacial caps covering Canada. If humans were here that early, they must have come from Europe — as the Solutreans did later, ca. 18,000 years ago (see Roots of Cataclysm, Algora Publ. NY 2009).

  5. there is a smiley face at the top of the screen in the right side

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