But that isn't the only trick that's evolved in the face of malaria. There are also more than a hundred slightly different genes that cause a shortage of a protein involved in breaking down red blood cells. That makes it harder for the malaria parasite to sneak into a red blood cell. Another type of mutation that's been spreading lately blocks malaria parasites from hanging out in the placenta.
And it's not just malaria — evolution has helped spread adaptations that protect against leprosy, tuberculosis, and cholera in certain populations as well. Some scientists have suggested that living in cities helps this process along.
3. Blue eyes
Blue eyes are another recent-evolved trait and scientists have determined it came from a mutation in a single ancestor 6,000-10,000 years ago.
The mutation affected the OCA2 gene, which codes the protein necessary for producing melanin, which gives our skin, hair and eyes their color. This essentially "switched off" the ability to have brown eyes by limiting the melanin produced in the iris, and "diluting" the eye color from brown to blue.
Having lighter eyes didn't give anyone a particular survival advantage, but because the gene for blue eyes operates similarly to a recessive trait (though it's a little more complicated), blue-eyed fathers could better guarantee that their children were, in fact, their own.
4. High-altitude breathing
Tibetans live in one of the least hospitable, and therefore one of the last populated areas on the planet: the Himalayan mountains. And their ability to handle the low-oxygen levels up there is not due to mere hardiness — it's coded into their genes.
One study compared indigenous Tibetans, who live at altitudes above 10,000 feet in the Himalayan highlands, with Han Chinese from Beijing, who are closely related genetically but live right around sea level elevation.
The researchers found that the Tibetans' blood was genetically predisposed to produce more of the oxygen-transporting hemoglobin protein. Still up for debate is when this mutation occurred, but some geneticists have estimated it happening as recently as 3,000 years ago (though unsurprisingly, archaeologists push that date much further back).
5. Missing wisdom teeth
It's not just oral surgeons who are removing wisdom teeth (third molars) from human mouths — evolution is playing a part too.
On our evolutionary road to becoming humans, our big brains crowded our skulls and narrowed our jaws, making it difficult for the third row of molars to emerge from the gums.
And after we began cooking our food and developed agriculture thousands of years ago, our diet became softer. This switch to soft grains and starches required less strenuous chewing than our past hunter-gatherer diet. This meant our jaw muscles didn't grow as strong as they used to, keeping the wisdom teeth beneath the gums increasing the risk of painful and deadly infection.