Posted by RJG on December 15, 2008 • PSIVgml - an endogenous primate lentivirus.
The grey mouse lemur is found only in Madagascar
A lentivirus fossil identified in the genome of a Malagasy primate.
The human immunodeficiency viruses HIV-1 and HIV-2 arose through cross-species transmission of lentiviruses from primates to humans. It is well established that these transmission events occurred in West and Central Africa, where lentiviruses are known to circulate among wild apes and monkeys. However, it has generally been assumed that natural lentivirus infections of primates are restricted to the African mainland.
In direct contradiction of this notion, we identified an endogenous lentivirus in the genome of a Malagasy primate - the grey mouse lemur (Microcebus murinus - pictured). Grey mouse lemur prosimian immunodeficiency virus (PSIVgml) was identified by in silico screening of whole genome sequence data, and contains some derived features, such as a vif gene, but lacks certain genes found in simian lentiviruses, such as vpr. PSIVgml is also phylogenetically intermediate, grouping between the feline and simian immunodeficiency viruses in trees.
The European rabbit (Oryctolagus cuniculus)
Rabbit endogenous lentivirus K (RELIK) - an ancient endogenous lentivirus.
Unlike many other retrovirus groups, lentiviruses - the genus that includes HIV-1 and HIV-2 - have not previously been identified as endogenous sequences in animal genomes. In the absence of a genomic fossil record, the lentivirus genus has been thought to have a relatively recent origin (in evolutionary terms). For example, whereas some retrovirus groups appear to predate the divergence of mammalian orders more than 60 million years ago, studies of the feline and primate lentivirus subgroups have suggested they could have originated no more than 1–2 million years ago.
We have discovered the first example of an endogenous lentivirus, which we call rabbit endogenous lentivirus K (RELIK), in the genome of the European rabbit. This discovery enabled us to peform the first ever investigation of lentivirus evolutionary history using genomic fossils.