[The origin and evolution of HIV].

Understanding HIV-1 evolution is crucial for tracing its ape origin as well as considering genetic variation within and among hosts. Here, we review the current evidence documenting cross-species transmission from chimpanzees and gorillas to human. First, each HIV-1 groups M, N, O and P arose through 4 different cross-species transmissions of SIVcpz and SIVgor. Second, in vitro studies demonstrate that SIVcpz and SIVgor have many of the biological properties necessary for establishing a persistent infection in humans.