Scientists have discovered the oldest known near-complete HIV genome from tissue samples preserved in 1966. The samples came from the Democratic Republic of the Congo, and the oldest known HIV genome was from blood samples taken from the Congo in 1976. Ancient gene sequences help determine when a virus’s genes mutate, help ingend scientists and determine when it spreads to humans.
According to the genetic sequence of the virus sample, HIV first spread from chimpanzees to humans in Central Africa sometime in the early 1900s. There are several strains of the virus, of which HIV-1 is in the M group of viruses accounting for 95%.