Gene That Helped Humans Survive Migration Out Of Africa Increases Arthritis Risk – IFLScience

A single gene mutation that helped early humans survive in Europe and Asia during the Ice Age may alsoincrease the risk of arthritis in modern-day humans.

Researchers from the Stanford University School of Medicine and Harvard University have found a gene mutation thathelped our ancestors survive colder temperatures by coding for shorter limbs, according to new research published in the journal Nature Genetics.

As modern humans migrated out of Africa between 50,000 and 100,000 years ago during the last Ice age, they were faced with colder temperatures.Agenetic variant for shorter limbs may have helped thembetterwithstandfrostbite, the researchers argue. Shorter bones also meant there was less chance of breaking a bone if they slipped on ice.

Theres a downside, however.The gene in question, known as GDF5, which isinvolved in bone growth and joint formation,also increases one'srisk of osteoarthritisa condition that causes joints to become painful and stiff. In humans, mutations in the GDF5 gene have been shown to belinked to a 1.2 to 1.8 times increase in the risk of osteoarthritis.

Of course, the prospect of painful joints is not a pretty one, nor particularly useful if youre hunting mammoths inIce AgeEurope. However, the risk from cold temperatures may have outweighed the risk ofosteoarthritis,which usually occurs after prime reproductive years. The gene was repeatedly favored as early humans migrated out of Africa and moved into colder corners of the world. Its thought that at least half of Europeans and Asians have the gene variant, yet it remains relatively rare in African populations.

Because its been positively selected, this gene variant is present in billions of people, David Kingsley, professor of developmental biology at Stanford, said in astatement. So even though it only increases each persons risk by less than twofold, its likely responsible for millions of cases of arthritis around the globe."

Armed with thisfresh insight, Professor Kingsley believes their study could havepractical implications in the world of medicine.

"This is an incredibly prevalent, and ancient, variant. Many people think of osteoarthritis as a kind of wear-and-tear disease, but theres clearly a genetic component at work here as well," he added. "Now weve shown that positive evolutionary selection has given rise to one of the most common height variants and arthritis risk factors known in human populations.

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Gene That Helped Humans Survive Migration Out Of Africa Increases Arthritis Risk - IFLScience