Researchers at the University of Texas have found that a retrovirus (a virus that enters through the RNA genome, rather than the DNA) related to HIV became stably integrated into the genome of several lemurs around 4.2 million years ago. The new analysis of the virus (prosimian immunodeficiency virus) offers new insights into the evolution of lentiviruses (slow viruses characterised by a long incubation period).
When the viruses replicate, they integrate with the chromosomes of the host cells, and through generations and generations of integrating they may eventually become part of the genetic material of the host species. This process is called endogenization. Until now the process was believed to be rare for lentivurses as it is an evolutionarily elusive group of retrovirsues that affect diverse mammals, including humans in the form of HIV. These findings are very important as they allow future analyses into the understanding of lentiviruses, including HIV.
Source: http://www.sciencedaily.com/releases/2009/03/090319224524.htm
