It sounds like there's precious little certainty to be had [1]:
So far, nobody has recovered ancient DNA from archaic human skeletal remains in Africa. The 2000-year-old Ballito Bay boy is not the oldest, but there are no DNA results from truly archaic specimens, like the Kabwe skull from Zambia. As a result, we don’t have the kind of record within Africa that geneticists have built for Neanderthals and Denisovans in Eurasia...
Morphology does not tell the story of modern human origins...Did short faces and rounded braincases really make a difference to the survival and success of modern humans? Maybe they were chance legacies of the population that gave rise to our gene pool. We don’t know.
Conclusion:
We have to discover more fossils. That’s the way that we will start to solve these new problems and shed light on old mysteries.
So far, nobody has recovered ancient DNA from archaic human skeletal remains in Africa. The 2000-year-old Ballito Bay boy is not the oldest, but there are no DNA results from truly archaic specimens, like the Kabwe skull from Zambia. As a result, we don’t have the kind of record within Africa that geneticists have built for Neanderthals and Denisovans in Eurasia...
Morphology does not tell the story of modern human origins...Did short faces and rounded braincases really make a difference to the survival and success of modern humans? Maybe they were chance legacies of the population that gave rise to our gene pool. We don’t know.
Conclusion:
We have to discover more fossils. That’s the way that we will start to solve these new problems and shed light on old mysteries.
[1] https://medium.com/@johnhawks/the-story-of-modern-human-orig... via https://news.ycombinator.com/item?id=16234903