Some more on Neanderthals and Denisovans: Mystery human species emerges from Denisovan genome:-http://www.newscientist.com/article/dn24603-mystery-human-species-emerges-from-denisovan-genome.html#.UouaFtK8Cy4?-"Denisovans harbour ancestry from an unknown archaic population, unrelated to Neanderthals."-At the end it says "inbreeding was rife in human evolution" - but I think they mean interbreeding!