Scientists Say They've Found One of the First Modern Instances of Genetic Mutation in Humans
You might think humans have reached their natural evolutionary peak—we've got thumbs, big brains, and the ability to start editing our own DNA, so what's left to evolve? A lot of things, actually.
Scientists have already discovered evidence that some humans have mutated to become immune to heritable diseases, while a new study of the Bajau people of southeast Asia, who spend up to five hours a day holding their breath in order to hunt underwater, suggests that they have mutated to grow larger spleens to help them deal with low oxygen situations.
The Bajau people are sometimes called "sea nomads," and portions of them live mostly on the water, either in houseboats or stilted huts. The Bajau hunt all kinds of sea life, including octopus, fish, and lobster, and do so mostly without modern equipment (like scuba gear or fishing trawlers). Instead, hunters dive with basic masks and a spear, sometimes for eight hours a day.
They're the envy of modern freedivers, sportspeople who swim in deep water without breathing apparatuses, but how the Bajau have become so good at holding their breath has remained a mystery.
For many freedivers, the constant battle against low oxygen can scar their lungs, damage their bodies, and even cause blackouts while diving.
Researcher Melissa Ilardo, the lead author of the new study, decided to study the Bajau people by examining their spleens with an ultrasound device and collecting genetic material both from Bajau people who dived and those who did not. What she found challenges everything scientists know about the human body, evolution and genetic mutation.
Ilardo discovered that the Bajau generally have enlarged spleens, even those that don't engage in freediving. Apparently, enlarged spleens help Bajau divers by releasing more oxygenated blood when the body senses it's running out of air. The larger size of the organ may be the result of the gene PDE10A, which is one of over two dozen genetic mutations found in the Bajau people. Interestingly, the mutation seems to be different from the one that allows Tibetans to survive in the low-oxygen slopes of the Himalayas.
So if you're ever in doubt about humanity's evolutionary fate, take comfort in the fact that mutations are still happening—and endowing some people with borderline superpowers.