Why Jews drink, but don't get drunk (OK, grain of salt) Steve Sailer pointed me to this article about Jewish resistance to alcoholism. Here's an excerpt:

The mutation, called ADH2*2, is involved in the way the body breaks down alcohol in the bloodstream. Scientists are unsure exactly how it protects against alcoholism, but it is thought to increase levels of the toxic chemical acetaldehyde - a by-product of alcohol metabolism. At high levels, acetaldehyde causes headaches, nausea and flushing. Almost all white Europeans lack the ADH2*2 variation and so produce less of the by-product. Thus drinking tends to be more pleasurable, increasing the risks of alcoholism.

Of course, one can figure out why those of us interested in race differences might have an interest in genes like this...but wait, many behaviors are too complex to find any causal link to gene a, b, c, d.... Well, at least now.