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BY STEVEN HSIEH

ANCHOR CHRISTINA HARTMAN

You're watching multisource science video news analysis from Newsy. 

Copulation with cavemen may have boosted our immune systems.

A new study suggests our ancient ancestors acquired disease-fighting genes from interbreeding with Neanderthals – and their cousins, the Denisovans.

So, how’d we discover the benefits of Stone Age Sex?  Well, researchers at Stanford found specific variants – or alleles – of the HLA immune system gene in both the Neanderthals of Europe – and the Denisovans of Asia.  An article in The Scientist explains the significance…

“…the archaic alleles were more common among Europeans and Asians and less common among Africans, pointing to a likely influx of these alleles after modern humans left Africa and came into contact with Neanderthals and Denisovans.”

Still confused? Check this out.

This map shows the current worldwide spread of the gene, HLA-A. Red indicates areas of high concentration, and blue – low. Tens of thousands of years ago, our blue African ancestors conquered red territory.  But in the midst of all the fighting, some of them sought one-night stands with the Denisovans – and acquired HLA-A.

But our fornication with the Flintstones has its downsides.  A researcher tells The Guardian – the same genes that help us, can also hurt us.

"…it looks to me like modern humans have acquired these alleles, but we weren't kind of prepared for them, we hadn't grown up with them, and in some circumstances, they can start to attack us as well as the viruses and other pathogens."

But not everyone’s convinced. A University of Wisconsin professor says – let’s not count out evolution’s role in shaping our immune systems. He writes about rarity of HLA-A in Africa…

“…if it has any tiny disadvantage against malaria, for instance, its rarity in Africa is easily explained as a function of recent evolution, while its presence almost everywhere outside Africa would be no surprise even if there were never any interbreeding… Saying that HLA-A*11 in modern humans came from Denisovans is simply premature.”

For more on the transfer of “genes” in the conjugal cave – check out the full study in the journal, Science.

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Transcript by Newsy.