Determining Migratory Patterns of Early Humans — With Earwax!

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Earwax is mostly gross, but it serves a few purposes: protecting our ear canals from bacteria and dryness, assisting in cleaning and lubrication, and — surprisingly — helping anthropologists determine the migratory patterns of early humans.

While most native English speakers have wet, amber-to-brown colored earwax, there's a second type — dry, gray, and flaky. Which type of earwax you have is determined genetically, with the dry type being recessive and perhaps the result of a genetic mutation somewhere along the way. For some reason, the mutation is common among East Asians. An estimated 97 to 100 percent of people of European and African descent have the wet-type earwax, while 90 percent or more of those descended from East Asians have the dry type.

The gene that controls the relative wetness of earwax is tied to sweat, generally, and the prevailing belief amongst researchers is that the recessive gene, insofar that it reduces sweat output, had advantages in the colder climates of northern China (where, along with Korea, dry earwax is most common), where the mutation seems to have begun.

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