HIV was born out of a union more than a million years ago between two viruses that infected different species of monkey, a study of the genetic history of HIV-like viruses suggests.
The union took place when chimpanzees preying on the monkeys contracted the viruses, which then combined to form a new type of simian immunodeficiency virus (SIV), the primate version of HIV. It wasn’t until the 1930s, though, that this jumped to humans feeding off chimpanzee bush meat in what is now the Democratic Republic of Congo.
SIV in chimps is the precursor to HIV-1, the most widespread form…
