Clues to Resistance
In 2000, 23-year-old Gimble from Gombe National Park -- made famous by Jane Goodall -- became the first wild chimpanzee to test positive for simian immunodeficiency virus (SIV), the primate precursor to HIV. Now, he and hundreds of other wild chimpanzees across sub-Saharan Africa are helping researchers understand what makes some chimps more resistant to infection. Normally, SIV invades cells by binding to a receptor called CD4. But a new study identifies mutations that block certain virus strains from entering. Chimps born with these genetic variants are less susceptible to some chimpanzee viruses, and – more importantly -- to strains of SIV that infect the monkeys they eat. Copyright Ian Gilby.