Neanderthal Genes Helped Modern Humans Adapt to Cold

By Gemma Tarlach | January 29, 2014 12:02 pm

neanderthal

You’ve heard that Neanderthal DNA lives on in the genes of many modern humans — now there’s evidence that it helped our early ancestors adapt to life beyond the tropics and subtropics of Africa.

As gene sequencing becomes increasingly sophisticated, scientists have been able to prove that early modern humans traveling out of Africa to Europe and Asia interbred with Neanderthals already established in those regions. As a result, most non-African humans today have at least some Neanderthal genes.

But, using new techniques to zero in on traces of Neanderthal DNA in modern humans, researchers found the genes were not distributed evenly.

No Balls About It

Neanderthal-origin genes are concentrated in areas of the modern human genome that regulate the appearance of skin and hair. This finding, researchers say, suggests the genes were beneficial to modern humans by giving them characteristics that helped them adapt to colder climates (like thicker body hair, for example).

Even more unexpected, scientists discovered certain areas of the modern human genome had no Neanderthal DNA. In particular, genes on the X chromosome and those concerning the testes had no Neanderthal origin. Researchers believe these segments of Neanderthal DNA in a male hybrid must have reduced his fertility and thus were not passed on to later generations.

Neanderthal DNA Today

To determine Neanderthal DNA distribution in the modern human genome, authors of today’s paper, published in Nature, used a method comparing known Neanderthal genetic patterns with samples from more than 1,000 modern humans to find archaic genetic material from our long-lost relatives that has survived in our species’ genome.

A separate paper, published today in Science, compared the Neanderthal genome with the genes of more than 600 modern humans and reached similar conclusions.

Interestingly, while earlier studies have estimated that 1 to 4 percent of a modern, non-African human’s DNA has Neanderthal origins, authors of the Science paper found that about 20 percent of Neanderthal genes live on in modern humans. The researchers believe additional research based on a larger sample size may reveal that our extinct relatives contributed a much greater share to our genome than previously thought.

Image by erix! via Flickr

CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: genetics, human origins
  • mezmama

    “No Balls About It”? Really? Why the crassness? Did you think the article would be more readable/interesting by sinking to schoolyard terminology? Not sure I want to read further articles in Discover if this is the kind of journalism you practice. Get a little class, please.

    • jambii

      Er… maybe take a joke, or take things you read online with a grain of salt. Even if it’s from a website you like. :

      I don’t think lacking class was this author’s intention, but hey, we all make mistakes and we all interpret things differently, right?

      At least this article still has text in it, unlike other “journalists” online.

    • jambii

      Also, maybe you should take a quick look into your Disqus comment history before calling other things classless ;)

  • http://www.artfire.com/ext/shop/studio/Treasure_Quest earsz70

    I also had to look back to find the phrase at issue. It’s a dumb phrase but scarcely disturbing _ and similar crassness won’t stop me from reading science articles. However, I join in the rejection of the phrase.

  • Alexis Silvaggio

    Lighten up people, we don’t always have to use technical terms to be scientists. This article was very interesting and informative. Find something that actually matters to pick on!

  • Dan Jones

    What is more important is that this lack of X chromosome genes allows us to speculate that our African ancestors simple bred the Neanderthals out of existence. Only “purist” Neanderthals that did not mate with the newcomers in their territories would have continued to survive. Over the last 10s of thousands of years they never had a chance.

    • Herne Webber

      Actually, there is evidence from genetic analysis comparing earlier Neanderthals to later ones showing that they did not remain pure. However, that actually *supports* your hypothesis that H. sapiens bred them out of existence. Over time, the Neanderthal genome became saturated with Sapiens genes, with the potential consequence of diminished fertility for some (which Sapiens overcame in themselves by sheer numbers that kept rolling in in waves). Eventually, there would have been a genetic percentage tipping point, after which H. neanderthalensis tribal members would have been more than half H. sapiens, and from there on, ‘they’ were us. I believe we are seeing similar patterns emerge within American populations, where minorities are absorbing European genes, to the end result that eventually those with minority ancestry will blend into the majority population, giving rise to blended people like me.

      P.S., 23andMe says I am 2.9% Neanderthal, which is almost as much as if I had a Neanderthal 3-greats grandparent! I found out I am also about 1/1024th each of West African and Oceanean (i.e., New Zealand, Australia, and the SW Pacific islands). The majority of my Euro ancestors have been here for about 3-400 years, so finding an African ancestor ten generations ago is no great shock. In terms of the ‘species concept,’ for a large number of species such as our own, there really is no such thing as ‘pure,’ because genetic introgression recreates species all the time.

      • Dan Jones

        Excellent analysis and I agree with your scenario for the future. It will be a great day when we think of ourselves as humans from the planet Earth and not of any particular race or nationality.

        PS, I have not had my genome analyzed, but as I am Scot, Welsh, Dutch, and German heritage, I suspect that I have a high Neanderthal content. Best regards.

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