Untying a Genetic Knot

In an intriguing piece of research, scientists have found that an ancient genetic variation that once protected people of African descent against a certain type of malaria may also make these individuals 40% more susceptible to infection by HIV, the virus that causes AIDS.
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"It helps in part to explain why HIV is so prevalent in Africa," says Robin Weiss, a virologist specializing in HIV at University College London and a co-author of the paper.

According to the study, about 90% of people in Africa and some 60% of African-Americans carry the variant gene. In Africa, the scientists estimate, roughly 11% of the HIV burden may be linked to this genetic variation.