Mitochondrial Eve

Of the thirty-three clans we recognize worldwide, thirteen are from Africa. Many people have left Africa over the last thousand years, a lot of them forcibly taken as slaves to the Americans or to Europe. but their recent genetic roots are quite clearly in Africa. Although Africa has only 13 per cent of the world’s population, it lays claim to 40 per cent of the clan. The reason for this is that Homo sapiens has been in Africa for a lot longer than any where else. The archaeology supports this statement, the study of human fossils supports it and now the genetics supports it too. There has been a very long time for mutations to accumulate in Africa. This means there has been time for new clans to form and become distinctive and recognizably different from one another. Different clans are more frequent than others in some parts of the continent, but there is no specific association between genetic clans and tribal structures. This is a reflection of the great antiquity of the genetic roots, which predate the formation of tribal and other classifications by more than a hundred thousand years.

Incredibly, even though the African clans are easily the most ancient in the world, we are still able to reconstruct the genetic relationships among them. Thus we probe the ancestors of the ancestors. At last, my dream of building a complete maternal genealogy for the whole of humanity was coming true. One by one the clans converge until there is only one ancestor, the mother of all the Africa and of the rest of the world. her existence was predicted in the original scientific paper on mitochondrial DNA and human evolution in 1987. Immediately she was dubbed ‘Mitochondrial Eve’ – hardly a convincing African name. She lies at the root of all the maternal ancestries of every one of the six billion people in the world. we are all her direct maternal descendant. But, just as Ursula and the others were not the only women alive at the time, nor was Eve. Estimates of the size of the human population one hundred and fifty thousand years ago are bound to be not much more than guess-work, but it may have been in the order of one or two thousand individuals. Of these, only Eve’s maternal lineage survives unbroken right through to the present day. The others withered away. But they, like Eve, would also have had maternal ancestors; so there is another woman even further back who was an ancestral mother of Eve and her contemporaries. She in turn would not have been alone, and another ancestral mother becomes a logical inevitability. This line of thought goes on and on, becoming increasingly pointless as wed reach back millions of years to the very beginnings of our species and the species from which we ourselves evolved. The dashed line on figure 7 indicates this even deeper genealogy through which our species, Homo sapiens, is connected to the other, extinct humans, the Neanderthals and Homo erectus, and eventually ;back to the common ancestor of human and other primates

For our purpose we need only go back in time as far as Mitochondrial Eve. The genetics tells us very clearly that modern humans had their origins in Africa within the last hundred and fifty thousand years. At some point, about a hundred thousand years ago, modern humans began to spread out of Africa to begin the eventual colonization of the rest of the world. incredible as it may seem, we can tell from the genetic reconstructions that this settlement of the rest of the world involved only one of the thirteen African clans. It could not have been a massive movement of people. Had hundreds or thousands of people moved out, then it would follow that several African clans would have been found in the gene pool of the rest of the world. But that is not the case. Only one clana, which I have called Laura, was involved. It is theoretically possible from the mitochondrial DNA evidence that only one modern human female, one woman, left Africa and that from this one woman all of us in the rest of the world can claim direct maternal descent. I think this highly unlikely, since she would have had contemporaries in her foraging band. But the numbers must have been very small. This was no mass exodus. Lara herself was not in the party. She probably lived in Kenya or Ethiopia; certainly in Africa. We know this because many Africans today are members of her clan. So she must have lived her life in African, unaware of her gift to the world, while it was her descendants that began to move out. Even so, it it quite astonishing conclusion that the whole of the rest of the world can trace their maternal ancestry directly back to Lara. She is truly the mitochondrial Eve of the rest of the World. ~ Pages 276 to 278