by Bryan Sykes
The seven clusters had ages of between 45,000 and 10,000 years. What these estimates actually tell us is the length of time it has taken for all the mutations that we see within a cluster to have arisen from a single founder sequence. And, by purely logical deduction, the inescapable but breathtaking conclusion is that the single founder sequence at the root of each of the seven clusters was carried by just one woman in each case. So the ages we had given to each of the clusters became the times in the past when these seven women, the clan mothers, actually lived. It required only that I gave them names to bring them to life and to arouse in me, and everyone who has heard about them, an intense curiosity about their lives. Ursula, Xenia, Helena, Velda, Tara, Katrine and Jasmine became real people. I chose names that began with the letter by which the clusters had been known since we had adopted Antonio Torroni’s alphabetic classification system. Ursula was the clan mother of cluster U. Cluster H had Helena at its root. Jasmine was the common ancestor for cluster J; and so on. These were no longer theoretical concepts, obscured by statistics and computer algorithms; they were now real women. But what were they like, these women to whom almost everyone in Europe is connected by an unbroken, almost umbilical thread reaching back into the deep past?
There are a few qualifications you needed to be a clan mother. The first is that you needed to have daughters. That is obvious, because the gene we are following, mitochondrial DNA, is passed from mother to daughter. A woman who had only sons could not be a clan mother because her children would never pass on the mitochondrial DNA they received from her. So that is the first rule. The second is that you had to have at least two daughters. It’s easiest to see why by looking at things the other way round, from the present to the past. The clan mother is the most recent maternal ancestor that all the members of a clan have in common. Imagine a clan with ten million living members and imagine that we knew perfectly from the registry of births, marriages and deaths exactly how they are all related. As we went back in time, generation by generation, we would see the maternal lines slowly joining up. The lines in brothers and sisters would converge, after just one generation, in their mother. After two generations, cousins would converge on their maternal grandmother, their mother’s mother. Three generations ago it would be the second cousins whose lines coalesced in their maternal great-grandmothers. And so on. At each generation there would be fewer and fewer people in the clan who had maternal descendants living today. Eventually, hundreds or even thousands of generations ago, there would be only two women in the clan who could claim to have maternal descendants living in the twenty-first century. Further back still, the maternal lines of these two women would converge on a single woman – the true clan mother. And to be in that position she must have had not one but two daughters.
Figure 5
To clarify this rather tricky point take a look at Figure 5. I have drawn out an imaginary maternal genealogy of fifteen living women, represented by the white circles on the right-hand side. Only the ancestor marked by the arrow is the most recent common ancestor of all fifteen. Her mother is also a maternal ancestor of all the women, but she is not the most recent. Her daughter is. Equally, her two daughters, marked with asterisks, are both maternal ancestors of living women, but neither daughter is the maternal ancestor of all fifteen of them. If we called this a clan, then only the woman with the arrow is the clan mother. Exactly the same principle applies whether there are fifteen people in a clan, or fifteen thousand or fifteen million. There is still only one clan mother.
A clan mother did not have to be the only woman around at the time and she certainly wouldn’t have been. But she is the only one who is connected through this unbroken maternal thread right through to the present day. Her contemporaries, many of whom will themselves have had daughters and grand-daughters, are not clan mothers because at some point between then and now their descendants in the female line either had no children or produced only sons. The lines died out. Of course, since we do not have records going back more than a few hundred years, let alone a few thousand, we can never hope to know the precise genealogy all the way back to the clan mother. All we can do is use the DNA sequences and the slow ticking of the molecular clock to reconstruct the main events as mutations slowly appear in these maternal lines. Even though we can never arrive at a perfect reconstruction of the true genealogy, this does not detract from the logical inevitability of there being only one mother for each clan. That conclusion is inescapable.
What remain open to debate are the exact times and places that these seven women lived. I have made my best estimates of the times by summing the mutations that have accumulated in each of the seven clans. The locations I have chosen for the seven women, again my best estimates, are distilled from the present-day geographical distribution of the clans and their different branches.
Generally speaking, the likely geographical origin for a clan is not necessarily the place where it is most common today but the place where it is the most varied. For example, going back to the Pacific, the clan that is very common in Polynesia did not originate there. Even though it is extremely abundant, there is very little diversity within the clan in Polynesia: most Polynesians who are in that clan today have the same DNA sequence. On genetic grounds alone, the origin of the clan is much more likely to be further west in the islands of Indonesia around the Moluccas. Even though the clan is not particularly common on the Moluccas today, there is a lot more variation within it there than in Polynesia. Only a fraction of the population moved out to Polynesia, so the diversity within the clan drops. In native Taiwanese, the diversity within the clan is even higher although, as in the Moluccas, it is not especially common. That makes it likely that Taiwan is an even earlier origin of the Polynesian clan than the Moluccas. When it comes to Europe, although we lose the simplicity that comes through dealing with discrete island populations, the same considerations apply. Clan origins are likely to be near the locations where they are the most variable today. Even so, this somewhat theoretical argument has to be tempered with realism. The mother of a clan which is twenty thousand years old cannot have lived in the north of Scotland, even if that might be where the clan is most varied today, for the very practical reason that Scotland was covered in ice at the time. I freely admit that there is a considerable element of uncertainty about exactly where these women lived. Indeed, while I would be alarmed if an equal uncertainty surrounded the exacting science behind the genetics, I somehow feel an element of mystery surrounding certain aspects of these seven individuals is not inappropriate.
As I became more engrossed in these seven women, I began to imagine what existence was really like for them. I was filled with an intense curiosity about their lives. Having let the genetics direct me to the times and places where the seven clan mothers most likely lived, I drew on well-established archaeological and climatic records to inform myself about them. The record of past temperatures is held in the frozen cores taken from the polar ice caps. Raised and submerged beaches mark out the sea-level changes which have been such a feature of the past fifty thousand years. The vegetation leaves its mark in pollen which survives for thousands of years after it was shed by the flower that made it. The changing styles of tools made from stone and bone that are excavated from sites of human habitation record the ebb and flow of technological progress. The animal and fish bones that litter the same sites tell of our ancestors’ diet. All these pieces of tangible evidence combine with the genetics to recreate the imagined lives of these seven women, Ursula, Xenia, Helena, Velda, Tara, Katrine and Jasmine. They were real people, genetically almost identical to us, their descendants, but living in very different circumstances. What lives they must have led.
Come with me now on a journey into the deep past. Guided by the unbroken genetic threads that link us to our ancestors, we can travel back to a time before the dawn of history, to a world of ice and snow, of bare mountains and endless plains, to meet these remarkable women – the Seven Daughters of Eve.
; 15
URSULA
Ursula was born into a world very different from our own. Forty-five thousand years ago it was a lot colder than it is today, and would get colder still in the millennia to come leading up to the Great Ice Age. Ursula was born in a shallow cave cut into the cliffs at the foot of what is now Mount Parnassus, close to what was to become the ancient Greek classical site of Delphi. The cave mouth looked out across a wide plain a thousand feet below which led away to the sea twenty miles off to the south. Today this same plain is filled with the dark green of ancient olive groves; then it was a landscape of scattered woodland pressed up close against the mountain slopes with open grassland beyond. The coastline was several miles further from the cave than it is today. This was a consequence of the lower sea level that prevailed when more of the oceans’ water was locked into the ice and snow of the polar ice caps and enormous glaciers filled the valleys of the great mountain ranges. Temperatures would carry on falling for another twenty-five thousand years as part of the regular climatic cycle that has been going on for at least four hundred thousand years and will no doubt continue far into the future.
Of course, Ursula was completely oblivious to these long-term changes – much as we are today in our everyday lives. What mattered to her and her band of twenty-five was the here and now. Ursula was her mother’s second child. The first had been taken by a leopard when he was only two, in a raid on a temporary camp one dark night. This was a tragic but not uncommon occurrence in Ursula’s world. Many children, and occasionally adults too, were hunted and killed for food by lions, leopards and hyenas. Though it was a sad and serious blow for Ursula’s mother to lose her only child, it did at least mean she could get pregnant again. While she was nursing her son her periods had stopped, she no longer ovulated and could not conceive. This was a deliberate evolutionary adaptation to space out the children. Only when one child could walk well enough to keep pace with the seasonal migrations of the band would another be conceived. And that could take three or even four years. So, a year after she lost her son, she gave birth to Ursula.
It was March, the days were getting longer and the band had moved up from the coast where they had spent the winter. It was a good time of year; Ursula’s mother always looked forward to the spring. The coast in winter was damp and miserable. There were no caves to shelter in and she had to do the best she could in crude shelters of wood and animal skins. It wasn’t much of a home, and the living was difficult and uncomfortable to say the least. But they had to come down from the mountains: it was too cold up there, and in any case all the game on which they depended had retreated to the lower ground. There was plenty of it, but it was hard to catch. Her particular favourite was bison, which congregated on the plain in reasonable numbers at that time of year. But they were practically impossible to hunt down on foot and in the open. It was difficult and dangerous work. They were wary, hungry themselves and very bad-tempered. Only the year before two young men had been trampled to death in a stampede; since then, everyone had decided that it was just not worth it, and bison hunting in the winter was off limits. The loss of two hunters from the small band was a serious business, because it meant that there were extra mouths to feed in the shape of the bereaved women and their children. But the band only survived by co-operation, and there was no question of abandoning the dependants to their fate.
With bison hunting ruled out, the only food coming into the winter camp was either scavenged from carcasses or the occasional red deer that could be ambushed in the woods higher up the slopes. Scavenging was a depressing business for the hunters, and not without risk. They walked for miles, keeping an eye open for the signs of a kill made by a lion or a leopard. They might be lucky and spot the kites circling overhead if it was a clear day, but more often than not it was just a question of trudging round the usual circuit and listening out for the dreadful chatter of hyenas as they fought over the rapidly disappearing carcass. There had to be at least five people for a successful raid against a pack of hyenas. Making as much noise as possible, they rushed the carcass and scattered the hyenas before the beasts had a chance to realize what was going on. Then two of the group got on with the business of slicing off whatever meat was left while the others confronted the caterwauling hyenas that always hung around and made repeated lunges at either people or carcass. They pelted the beasts with stones and yelled to keep them back until the butchers had salvaged what they could, including the ribs, which were rich in marrow. Then it was a question of a hasty and organized retreat, with more stone-throwing and shouting as they left the scene. The trick was to leave at least some of the carcass behind, and to cover up what they had managed to collect under a skin. That way the hyenas eventually stopped following and returned to what was left. It was miserable, degrading work. The hyenas were awful, with saliva dripping from their disgusting mouths and making that frightful noise. There was nothing noble about this way of making a living, and everyone wanted to get off the soggy plains as quickly as possible and back to the mountains where at least they could hunt properly.
As soon as the first swifts appeared overhead, back from spending the winter in Africa, the band struck camp and started north for the mountains. The idea was to get there before the bison moved up to their summer pastures on Parnassus; that way there was a good chance of ambushing them as they filed through the steep-sided gorge below the cave. But even that wasn’t simple. If men had been trampled in a bison stampede on the open plain, imagine how much more dangerous the herd was in the tight confines of a gorge only 10 metres across at its narrowest point. As usual, there was an argument about the best way to go about it. This happened every time. Some people advocated blocking the gorge and diverting the lead animals into a side couloir where they could be stoned and speared to death. The trouble with this approach was that some bison, who definitely sensed what was going on, had a nasty habit of turning round when cornered and charging straight back. The prospect of facing a ton of charging muscle and horn was too much for some people, and they shot up the rock face. When the escaping animal got back, snorting and sweating, to the main herd, this panicked the whole lot and they charged through the gorge at enormous speed. The advocates of a less audacious method pointed out the dangers of this direct attack and argued that it was simpler to wait until the main herd had gone through the gorge and pick off the stragglers. This wasn’t a particularly heroic approach, but it did usually work. The bison bringing up the rear were usually the old members of the herd, but they still tasted better than scraps scavenged from the hyenas.
While this argument was going on, Ursula’s mother withdrew to the shelter of the spring camp in the cave. Even though it was not uncommon for children to be born when the band was on the move, it was a lot more comfortable in a settled camp. The cave was dry and it was warming up as the sun rose higher in the sky. She was very glad to have made it before the birth. From the smell that hung around the back of the shelter it was obvious that it had been used as a winter lair by a cave bear. These huge and fearsome creatures, bigger than even the largest Alaskan grizzly, were a dangerous threat to the band. They would quite often attack the hunting parties, and to kill a bear was a special event. But this particular bear had left its hibernation quarters long since, and there was no danger that it would return before the autumn.
Ursula’s birth was uncomplicated and attended by her mother’s elder sister, who sliced the umbilical cord with a sharp flint blade and tied it off. Like all human babies before and since, Ursula announced her arrival with a loud cry as the air was sucked into her lungs for the first time. Within seconds the fresh oxygen was absorbed into her bloodstream and surged round to her brain and muscles to take over where the placental supply left off. Almost immediately she was suckling urgently at her mother’s breast, drinking in the natural goodness of the milk. In this milk were also the antibodies she would need to fight off infections while her own immune system built itself up. If, as sometimes happened in the clan, the birth had go
ne badly and the mother had died, this also meant death for the child, for there was not yet any animal milk that could be substituted to sustain it.
Ursula spent only a few days in the cave before it was time for her mother once more to contribute to the main occupation of the clan – finding enough food to live on. The spring camp had been sited carefully, with a commanding view over the wooded slopes below and close to the gorge through which the bison must pass on their way to the summer pastures on the hills. This spot had been noticed only a few seasons before by a hunting party exploring the region from their main base further east. It was already occupied, not by members of another band but by a small group of a completely different kind of human, Neanderthals. The hunting party had given them a wide berth. These were very strong creatures, stocky and built to withstand the cold; but they showed no particular aggression to the newcomers.
When they returned the following year, the camp was abandoned. It was as if the Neanderthals, even though they would have been a match for the hunting party if it came to a straight fight, sensed the power of the new arrivals and feared them, preferring to leave a prize camp and retreat to higher ground rather than risk a confrontation. There were many stories of the Neanderthals in the band’s collective mythology, stories that were repeated around the camp fires in winter. They were rarely encountered nowadays but they must once have been more common. In virtually all of the old, abandoned caves, the band came across the heavy hand axes which were the Neanderthals’ principal tool. By the standards of Ursula’s fellows, these tools were crude and unsophisticated; they worked the same stone as the Neanderthals, but could make much better use of it. For instance, they would strike off thin slivers of flint and sharpen any dull edges by chipping away at them. All the men had to learn how to make their own flint knives and scrapers, but inevitably some were better at it than others – either better at selecting the right piece of flint in the first place, or better at judging exactly where to strike it to create the best flakes. The Neanderthals, from the evidence of stones left behind in the caves, had never got the hang of doing this.
