Latest genetic research was able to look into primate genomes, which they say could hold the key about the origins of HIV.  In a study that is scheduled to appear in the online version of Proceedings of the National Academy of Sciences, a team of researchers was able to screen sequence data on almost two dozen primate species and identified a lentivirus called pSIVgml in the gemone of a Madagascar gray mouse lemur (Microcebus murinus).

The research team from Stanford University suggested that HIV may not be a naturally-occurring virus among primates and it may have entered primate genomes between 14 million and 85 million years ago.  They also say that this lentiviral-primate history could yield vital clues about lentiviral infections in modern times.

"The discovery of pSIVgml… unequivocally demonstrates that lentiviruses are capable of invading primate genomes," senior author and infectious disease researcher Robert Schafer wrote in the report.  "It illustrates the utility of endogenous sequences for the study of modern retroviruses, including lentiviruses."

Lentiviruses belong to a group of complex retroviruses that infect several types of animals.  HIV-1 is closely related to lentiviruses that circulate among African apes and monkeys.  Although transmission of HIV-1 to humans has created pandemic outbreaks, their primate cousins do not develop AIDS from the same type of virus.  Schafer’s team remains unsure about the long-term evolutionary history of lentiviruses, including its origins within primates and its interaction with other mammals.

The research team attempted to find endogenous retroviruses by using the tBLASTn computer program to screen the genomes of 23 primates.  They discovered that the genome of the gray mouse lemur contained several peptides matching lentiviruses, then they digged deeper into the genetic code and found sequences of lentivirus as well as viral coding regions.  The researchers called the new endogenous lentivirus as the gray mouse lemur prosimian immunodeficiency virus, or pSIVgml.