Teri Tupuaki and Gwyneth Roberts are related, according to Bryan Sykes, a geneticist at Oxford University's Institute of Molecular Medicine. Initially, this may not sound noteworthy, but Tupuaki is a fisherman in the Cook Islands of the South Pacific, while Roberts serves the school lunches in a small town in Wales. Also, Sykes says their common ancestor was a woman who lived about 140,000 years ago somewhere in Africa. Even that is not so startling, in scientific terms; what is startling is that the distant but detectable genetic relationship between Tupuaki and Roberts is the most distant one that Sykes' research into mitochondrial DNA has yet uncovered between any two living human beings. In other words, the rest of us are related too -- and most of us much more closely than Tupuaki and Roberts.
Indeed, if Sykes' findings are correct -- and so far they have withstood a great deal of hostile scrutiny -- among all of us who are of European descent, the relationship is, in planetary terms, pretty much that of kissin' cousins. Sykes believes that about 90 percent of Europeans can trace their maternal ancestry back to one of seven specific women, the most recent of whom lived about 10,000 years ago and the eldest about 45,000 years ago.
Of course these proto-European women had ancestors too, who at some point traveled out of Africa and into the Middle East before splitting up and beginning to colonize the globe. Go backward only a few thousand years before the ancestor shared by Tupuaki-Roberts and you reach the individual woman geneticists have dubbed the "mitochondrial Eve," who belonged to what was probably a very small human society in Africa. The only thing we know for sure about the mitochondrial Eve is that she had at least two daughters who themselves had children. And that she is the direct ancestor -- the 10,000th or so great-grandmother -- of you and me and everybody else on Earth.
Sykes has become a superstar in the red-hot field of genetics since he began publicizing his research into mitochondrial DNA, a peculiar form of the famous double-helix chromosome that is passed intact from mother to child, so that in any given individual it can be used to establish a chain of female ancestry. He did not himself discover the importance of mitochondrial DNA in tracing ancient human evolution, and gives full credit to American biochemist Allan Wilson, who did (with two of his students), but Sykes has surely done more to advance the field than any scientist.
Sykes has identified living relatives of the Iceman, the 5,000-year-old frozen corpse found in the Italian Alps, and of Cheddar Man, who is not a statue made of cheese but a 9,000-year-old skeleton found in England's Cheddar Gorge. He has established to a near 100 percent certainty that the bones found in 1991 in a birch forest outside the Russian village of Ekaterinburg were indeed those of Czar Nicholas II and his family, and that Anna Anderson, the woman who long claimed to be the Grand Duchess Anastasia, indeed was not.
"The Seven Daughters of Eve" is full of such juicy tidbits. Sykes has both an ingrained sense of how to make headlines and an unforced ability to explain the technical side of his work in layperson's terms, both of which probably drive his scientific rivals nuts. From their point of view, however, the explosive aspects of Sykes' work developed from his idea that you could use mitochondrial DNA to analyze not merely relationships between individuals but between groups. This was based on his theory (originally controversial, but now pretty well accepted) that mitochondrial DNA mutates at a constant rate. If you and I have the same mitochondrial DNA, our shared maternal ancestor was relatively recent. If our mitochondrial DNA varies by one mutation, she lived about 10,000 years ago; if by two mutations, then she lived 20,000 years ago and so on. (So there were 14 mutations between Tupuaku and Roberts, the largest number Sykes has seen.)
So by tracking differences in mitochondrial DNA between living people, and comparing them to DNA extracted from archaeological specimens, Sykes arrived at both his seven-clans-of-Europe theory and at the mitochondrial Eve. Along the way, he adds, he solved one of the great mysteries of paleoanthropology, establishing genetically that Polynesians migrated eastward from Southeast Asia rather than westward from South America (and that, since they traveled against the prevailing winds, they must be ranked among the greatest mariners the world has ever known).
It's hard to overemphasize the effect Sykes' work has had on the study of early humanity. A large and influential group of physical anthropologists has long argued that the point of human origin in Africa lay millions of years in the past, and that modern Homo sapiens evolved gradually in many different parts of the world. According to this school, modern Europeans might be descended from Neanderthal man, modern Africans from the early species known as Homo erectus and modern Asians from similar ancestor species found in China and Java.
Certainly not all these anthropologists have changed their views, but Sykes -- who insists he came to this subject as an agnostic -- comes down decisively on the side of their opponents, often called the "replacement" school or the "out of Africa" school. These scientists have argued in favor of "a much more recent expansion of Homo sapiens" from its African origin, an expansion in which the Neanderthals and other precursor species were driven away, outcompeted or simply killed off.
Neanderthal DNA, according to Sykes, is nothing like ours; they were undoubtedly our distant cousins -- perhaps twice as distant as the relationship between Teri Tupuaku and Gwyneth Roberts -- but they were a separate human species, now extinct, and not our ancestors at all. It is by no means certain that Neanderthals and modern Homo sapiens (known conventionally in Europe as Cro-Magnon man) could even interbreed, a question Sykes still hopes to solve.
Sykes admits to being a little surprised and disappointed by this conclusion (he doesn't discuss the Cain-and-Abel guilt we should perhaps feel on behalf of our genocidal ancestors), but the idea that humanity is a closer-knit family than we suspected is exciting enough on its own terms. Sykes' book focuses mainly on European ancestry, both for personal reasons and perhaps for marketing ones as well, but in no way does he argue that there is anything special or unusual about the DNA of European or so-called Caucasian people. Indeed, from the genetic point of view, he says, "objectively defined races simply do not exist."
The study of genetics and human evolution has sometimes been perverted to the service of bogus quests for "racial purity." What the science really tells us, in the words of Arthur Mourant, a pioneer in blood-group research, is that "the races of the present day are but temporary integrations in the constant process of ... mixing that marks the history of every living species." Sykes reports identifying unmistakably Polynesian DNA in an Edinburgh schoolteacher, Korean DNA signatures in Norwegian fishermen and African DNA in a white dairy farmer in rural England. Two fishermen on a remote Scottish island turned out to share Siberian ancestry -- but one by way of Finland, the other via Brazil.
I so thoroughly enjoyed "The Seven Daughters of Eve," with its combination of arrogance and humility and its detours into hamster genealogy (yes, really), the place of artistic creation in human evolution and bitchy scientific infighting, that it's painful to discuss one particular device Sykes resorts to: his "Clan of the Cave Bear" efforts to breathe life into his seven European foremothers. He has named all 33 of the clan mothers he has identified worldwide (there are undoubtedly more in Australia and Oceania), to remind himself that they were real people, he says. That is defensible, even charming. But the imaginative life histories we get of Xenia, Katrine, Jasmine, Helena, Velda, Ursula and Tara -- are these prehistoric women or this year's graduating class at Vassar? -- are highly unfortunate.
Sykes never seems fully comfortable with this material, which is simultaneously pedantic and purple ("Two gigantic tusks formed the door"), and one wonders if he felt pressured into it by Oprah-hungry publicists or tabloid journalists who demanded to know which of these hypothetical ancestors provided Jennifer Lopez's derrière. Speed-read through this stuff and it seems harmless enough: Neanderthals are banished, wolves are tamed, boats are created accidentally and seeds dropped on the ground are discovered to produce grain. Sykes' central lesson is so fascinating and indeed so urgent -- we are family, in the most tangible and literal sense -- that he can be forgiven a little hokum.