Our Immune Systems Are Linked To How Our Ancestors Had Sex

Posted: Oct 27 2016, 6:11pm CDT | by , in News | Latest Science News

 

Our Immune Systems Are Linked to How Our Ancestors Had Sex
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Scientists have been looking into what makes our immune systems tick and found that Europeans and Africans have significantly different responses, and the thought is that breeding with Neanderthals tens of thousands of years ago could be partly to blame for it.

This discovery explains what Africans have stronger immune systems than Europeans and why they get certain autoimmune conditions more often.

"I was expecting to see ancestry-associated differences in immune response but not such a clear trend towards an overall stronger response to infection among individuals of African descent," says geneticist Luis Barreiro from the University of Montreal in Canada.

Barreiro and his team looked at samples from 175 Americans, half of which had European ancestry and half had African ancestry. They took those samples and infected them with two different kinds of bacteria: Salmonella and Listeria.

They looked at these samples a day later and found that the macrophages from the African group reduced bacterial growth 3x faster than the European group did thanks to their immune system responses. This gives them an advantage with specific bacteria, but it also comes with certain disadvantages.

"The immune system of African Americans responds differently, but we cannot conclude that it is better," says Barreiro, "since a stronger immune response also has negative effects, including greater susceptibility to autoimmune inflammatory diseases such as Crohn's disease."

In addition, they found that the European samples could be linked to Neanderthal DNA. It is believed that when early humans left Africa and went into Europe, they would have encountered Neanderthals. The two species could have lived alongside each other for thousands of years, and it is possible that they procreated.

If that happened, it could have had an effect on their inflammation responses.

"Our results suggest that the immune systems of African- and European-descended individuals have evolved to better respond to the specific needs imposed by their specific environments," Barreiro told Live Science. "What is advantageous in one context is likely to be detrimental in another."

Both teams say that they will need to have more work to really find a reason and an explanation as to why our immune systems are so different. It could help us develop personalized plans and new medications.

"There is still much to do," says Barreiro. "[G]enetics explains only about 30 percent of the observed differences in immune responses. Our future studies should focus on other factors, emphasizing the influence of the environment and our behavior."

You can find the study published in Cell.

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<a href="/latest_stories/all/all/46" rel="author">Noel Diem</a>
Noel passion is to write about geek culture.

 

 

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