[Alter Kaker]

Two genera (ex: australopithicus, pan) no matter how closely related would never end up evolving in to the same descendant species.

Sorry to nitpick, but either an Australopithecine (or a species from a closely related genus, eg. Ardipithecus) is almost certainly the common ancestor of both Homo and Pan.

[ndt]

"Sorry to nitpick.."

Nitpicking is good.... It forces clarification.

Without a doubt you getting close to the point of divergence, but I don't think either of these two species could be ancestral to Pan.