Lentiviruses, a group of retroviruses including HIV and SIV, the simian version of HIV, have been infecting primates as far back as 16 million years ago according to DNA sequencing.

Researchers studied an antiviral gene called TRIM5 in 22 species of African primates. They found that a cluster of changes unique to the TRIM5 proteins in a subset of monkeys including macaques and baboons that suggests ancestral lentiviruses began infecting primates in Africa between 11 and 16 million years ago.

Original research paper published in PLOS Pathogens on August 20, 2015.

Names and affiliations of selected author

Welkin E. Johnson, Biology Department, Boston College, Massachusetts, U.S.A.