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5 signs humans are still evolving

When we think of human evolution, our minds wander back to the thousands of years it took natural selection to produce the modern-day man. But are we still changing as a species, even today? New research suggests that, despite modern technology and industrialization, humans continue to evolve. “It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans,” says Dr. Virpi Lummaa from the University of Sheffield’s department of animal and plant sciences.

But not only are we still evolving, we’re doing so even faster than before. In the last 10,000 years, the pace of our evolution has sped up 100 times, creating more mutations in our genes, and more natural selections from those mutations. Here are some clues that show humans are continuing to evolve.

We Drink Milk

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Photo: CC by Tim Ellis

Historically, the gene that regulated a human’s ability to digest lactose shut down as they were weaned off of their mother’s breast milk. But when we began domesticating cows, sheep and goats, being able to drink milk became a nutritionally advantageous quality, and people with the genetic mutation that allowed them to digest lactose were better able to propagate their genes. A 2006 study suggests this tolerance for lactose was still developing as early as 3,000 years ago in East Africa. That genetic mutation for digesting milk is now carried by more than 95 percent of Northern European descendants.

We Have Blue Eyes

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Photo: CC by mstofan

Originally, we all had brown eyes. But about 10,000 years ago, someone who lived near the Black Sea developed a genetic mutation that turned brown eyes blue. While the reason blue eyes have persisted remains a bit of a mystery, one theory is that they act as a sort of paternity test. “There is strong evolutionary pressure for a man not to invest his paternal resources in another man’s child,” says the lead author of a study on the development of our baby blues.

Because it is virtually impossible for two blue-eyed mates to create a brown-eyed baby, our blue-eyed male ancestors may have sought out blue-eyed mates as a way of ensuring fidelity. This would partially explain why, in a recent study, blue-eyed men rated blue-eyed women as more attractive compared to brown-eyed women, whereas females and brown-eyed men expressed no preference. 

See the rest at mental_floss.

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