News outlets discuss the findings of a study published in the Proceedings of the National Academy of Sciences showing two of the four groups of HIV-1 originated in Western lowland gorillas.

Agence France-Presse: Origins of HIV virus strains traced to gorillas (3/3).
New York Times: Two Strains of HIV Cut Vastly Different Paths (Zimmer, 3/2).
Reuters: Study finds gorilla origins in half of human AIDS virus lineages (Dunham, 3/2).