Homo sapiens
is not a finished product. In fact, there is evidence that modern
humans are evolving faster than ever before, as mutations and natural
selection continue to change us. How so? For one thing, we drink milk.
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.
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