HIV: from chimps to humans

HIV-1 strains in humans arose from three independent ape-to-human transmissions in the early 20th century, but the viral adaptation in humans remained unknown until now. Paul Sharp and colleagues from the University of Nottingham Queens Medical Centre in England compared full-length genome sequences of chimpanzee HIV strains with inferred ancestral sequences for three different phylogenetic HIV-1 groups in humans: M, N and O. They found that cross-species transmission in all three groups may have occurred through mutations of a single amino acid in the gag-30 (p17) residue of HIV. ¹

The findings are important for two reasons: "in this particular case, it shows that the virus adapts well in humans," says Eddie Holmes, a member of the Faculty of 1000, and researcher at Pennsylvania State University. "In [the] general picture of emergence, it shows you how many mutations you might need to go from one species to another.

"This paper shows for the first time that each of the strains has evolved the exact same mutation independently." This gives "very strong evidence," Holmes adds, that the mutation in this protein is critical for chimpanzees to infect humans.

Though changes in this protein were shown to be required for adaptation of HIV from chimpanzees to humans, the specific function of the protein is unclear, the authors wrote. A next step would be to address the exact consequences of what the mutation is, Holmes says.

These papers were selected from multiple disciplines from the Faculty of 1000, a web-based literature awareness tool (www.f1000biology.com).