So the story is that mankind's genes have been changing at a breakneck (historically speaking) pace, and that quite a few useful adaptations have sprung forth - and at least one adaptation of dubious usefulness:

For example, Africans have new genes providing resistance to malaria. In Europeans, there is a gene that makes them better able to digest milk as adults. In Asians, there is a gene that makes ear wax more dry.
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The only advantage of drier ear wax I can come up with is that it is ultimately easier to clean off the ear buds of iPods and Bluetooth headsets. Wonder what that means?