Researchers at the University of Chicago have found genetic evidence to support the sodium-retention hypothesis, a controversial 30-year-old theory that the high rate of hypertension in certain ethnic groups is caused, in part, by an inherited tendency to retain salt. In the December issue of the American Journal of Human Genetics, the researchers show that the frequency of one version of a gene that plays a crucial role in salt retention correlates with distance from the equator. Populations that live in hot, humid climates near the equator tend to have the normal version of that gene, which produces a very effective protein. Populations adapted to cooler climates tend to have a mutant gene that codes for a totally dysfunctional protein.
