Sunday, January 29, 2006

"...Ah, alas, earwax."

said Albus Dumbledore as he bit into what he had thought was a nice toffee Barty Bots Every Flavor Bean.

Rowling doesn't mention whether it was the wet or dry type. According to this NYT article by Nicolas Wade:

Earwax may not play a prominent part in human history but at least a small role for it has now been found by a team of Japanese researchers.

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.


It seems that earwax type might be an important genetic marker of human population movements over the ages.

The dry form, the researchers say, presumably arose later somewhere in northern Asia, because they detected it almost universally in their tests of northern Han Chinese and Koreans. The dry form becomes less common in southern Asia, probably because the northerners with the dry earwax gene intermarried with southern Asians carrying the default wet earwax gene. The dry form is quite common in Native Americans, confirming other genetic evidence that their ancestors migrated across the Bering straits from Siberia 15,000 years ago.

It also seems that the earwax gene is involved in sweating. I'm sure the Japanese scientists took considerable satisfaction in writing:

...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.

Nervous? Who? Me? What do you mean I look sweaty?