[Gladwin]

The human species is maybe 100,000 years old. The greater genetic variation in chimpanzees suggests that their species is much older. Perhaps they have been a stable species for 5 million years. Or, maybe humans are like cheetahs. Cheetahs have so little genetic variation that they suffered a population bottleneck sometime in the past.

[Doctor Stochastic]

This agrees with the Toba event. Looks like that eruption wiped out most of the human race.