Bertie Botts' genetic odyssey

I must admit, not many other clever thoughts came to mind about earwax. Nick Wade has an earwax genetics article telling you everything you probably wanted to know about it:

Earwax comes in two types, wet and dry. The wet form predominates in Africa and Europe, where 97 percent or more of the people have it, and the dry form among East Asians, while populations of Southern and Central Asia are roughly half and half. By comparing the DNA of Japanese with each type, the researchers were able to identify the gene that controls which type a person has, they report in the Monday issue of Nature Genetics.
They then found that the switch of a single DNA unit in the gene determines whether a person has wet or dry earwax. The gene's role seems to be to export substances out of the cells that secrete earwax. The single DNA change deactivates the gene and, without its contribution, a person has dry earwax.

There is some not-very-convincing hypothesizing about why dry earwax might have been selected in northern Asia:

They write that earwax type and armpit odor are correlated, since populations with dry earwax, such as those of East Asia, tend to sweat less and have little or no body odor, whereas the wet earwax populations of Africa and Europe sweat more and so may have greater body odor. Several Asian features, such as small nostrils and the fold of fat above the eyelid, are conjectured to be adaptations to the cold. Less sweating, the Japanese authors suggest, may be another adaptation to the cold climate in which the ancestors of East Asian peoples are thought to have lived.

Surely somebody can think of a better hypothesis than this. Although I must admit, one escapes me now.

In any event, I'm posting this because my genetics class has an assignment: write a 3-4 page paper about one human gene, and make it interesting. This article is a great example! It's one gene. There's something interesting about it. And it's unexpected. Great combination!