++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++++++++++++++++++++ Hi Geoff, None of the three articles cited can definitively rule out the possibility that the genetic remnants of some interbreeding of modern humans with Neanderthals and/or Denisovans. After reading these and a couple of other articles on this topic, it appears that the primary distinction between the Out of Africa hypothesis and the Multi-Regional hypothesis is where this interbreeding took place. The former seems to hold that it took place in Africa and the latter seems to assert that the interbreeding took place outside of Africa. Both hypotheses seem to acknowledge that there was some intermixing of the genes of these different lines. Please notice that #2 below states that there was only "limited interbreeding: one with Neanderthals and one with Denisovans" in the Out of Africa hypotheis. 1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2629215/ 2. http://en.wikipedia.org/wiki/Multiregional_origin_of_modern_humans >http://en.wikipedia.org/wiki/Neanderthal_extinction_hypotheses#Interbre >edin g >http://en.wikipedia.org/wiki/Denisova_hominin#Interbreeding_with_modern >_hum ans >http://www.ts-si.org/biology/30943-modern-humans-interbred-with-archaic >-hom inids-before-leaving-africa ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++ _+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++ We may never have the answer. All we have is clues from fossils. Maybe one day we will find some good remains where some DNA can be extracted. All humans from every corner of the world can successfully mate and have children. Whatever genes we acquired did not make us different enough to prevent breeding. =