Like other white Europeans I carry about 2.5 per cent Neanderthal genes, more than indigenous Africans. If we all walked out of Africa about 100,000 years ago, what is the explanation for this?
鈥� We didn鈥檛 simply walk out of Africa at any particular time. We originated there, and our ancestors sallied forth everywhere, but many genetically distinct populations took various routes over hundreds of thousands of years and their paths repeatedly diverged and converged.
In palaeontological terms, any event that lasts only for millennia is pretty abrupt. Our prehistory back to the estimated origin of agriculture probably spans less than 15,000 years. We are a recent, transient rabble 鈥� yet to us, family histories of 1000 years seem ancient.
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The Neanderthals were early colonists in Europe, sufficiently distinct from other populations of the genus Homo that geneticists can tell them apart. This factor has given us a good idea of when and to what extent Neanderthals merged with their successors. Perhaps hundreds of thousands of years after the Neanderthals, invaders from Africa introduced new genetic material: those that settled in Europe interbred with Neanderthals, so the proportion of such DNA in their descendants is greater than in other populations.
Jon Richfield, Somerset West, South Africa
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