Check out this New Scientist article about uku genetics. The researchers found that there are two different species of human ukus, and think that one must have come from Homo erectus and the other from Homo sapiens.
Waitaminute, did they just say having sex? With another species? Ewww...
The results suggest that our ancestors must have interacted with H. erectus either through fighting, sharing clothes or having sex, since both types of lice are now found on modern man and lice can only jump from one species to another if there is direct contact.
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