The creation of this taxon is the result of the current idea that the least similar species of a trichotomy should be separated from the other two. Through DNA comparison, scientists believe the Pan/Homo divergence was completed between 5.4 to 6.3 million years ago, after an unusual process of speciation that ranged over four million years. It is interesting to note that no fossil species on the Pan side of the split have been determined; all of the extinct genera listed in the table to the right are ancestral to Homo, or are offshoots of such. However, both Orrorin and Sahelanthropus existed around the time of the split, and so may be ancestral to both humans and chimpanzees.
In the proposal of Mann and Weiss (1996), the tribe Hominini includes Pan as well as Homo, but as separate subtribes. Homo (and, by inference, all bipedal apes) is in the subtribe Hominina, while Pan is in the subtribe Panina.