Drunken Fruit Shaped Ancestors

Researchers have found that a single mutation in the ADH4 gene appeared in the ancestors of humans and African great apes about 10 million years ago and sharply improved their ability to metabolize ethanol. This meant roughly a 40-fold increase in ethanol metabolism, which helped those ancestors eat fallen, fermenting fruit on the forest floor without being as impaired by alcohol. In practical terms, natural selection would have favored ancestors who could process ethanol better, because intoxication would have made it harder to defend territory, find food, and survive.

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