segunda-feira, 26 de março de 2012
Seven Daughters of Eve (first picture)
All Daughters of Eve (second picture)
Bryan Sykes's thesis
Click the images to enlarge them.
You can find a great site that explains all these questions.
It is an entirely logical, yet still awe-inspiring fact, that we are all related to each other through our mothers. Over the past ten years, research by Professor Bryan Sykes at Oxford University has identified just 36 women, who lived thousands of years ago, from whom almost everyone on Earth is directly descended through the maternal line. Professor Sykes has named these women and determined upon which continent they lived. The so-called "Seven Daughters of Eve" subgroup represents the seven-clan mothers from whom almost all native Europeans are descended.
There was actually nothing remarkable about any of these clan mothers when they were alive. We know that each one of them must have survived long enough to have children and that each had at least two daughters, starting off lines of descent that reach right down to all of us living today. These were real people, real women who brought up families, but who lived in very different circumstances to those that we enjoy today. These really were our true ancestors.
The 36 clusters (or clans) that have so far been identified vary in frequency across locations, but there is no specific association between genetic clans and tribal structures. This is a reflection of the great antiquity of our genetic roots, which predate our modem notions of race, tribe or other ethnic classification system by more than a hundred thousand years.
Africa lays claim to 13 of the maternal clans. Although these are easily the most ancient clans in the world, a reflection of Africa's status as the cradle of humankind, it is still possible to construct the genetic relationship between them. By doing this it is possible to show there is one maternal ancestor for all of Africa, and therefore for the rest of the world. She is referred to as 'Mitochondrial Eve', and is shown on your certificate.
Obviously, she would not have been the only woman alive at the time, but it is only her maternal lineage that has survived unbroken to the present day. She in turn would have had an ancestral mother, and this line reaches back millions of years to the very beginning of our species, Homo sapiens.
Although modem humans had their origins in Africa, only the descendants of one of these clans, Lara, have so far been found in the peoples of the rest of the world. Lara probably lived originally in what we now know as Ethiopia.
The vast majority of native Europeans are descendants of 12 clans, which includes the Seven Daughters of Eve. Of these dozen clans, descendants of Helena make up over 45% of the European population.
The Seven Daughters of Eve
Ursula (Latin for she-bear)
Ursula lived about 45,000 years ago in what is now northern Greece. She was among the first arrivals of a new, modern human to set foot in Europe. She was slender and graceful, in marked contrast to the thickset Neanderthals with whom she and her clan shared the land for another 20,000 years. Her kind brought with them a new and more sophisticated type of stone tool with which to hunt and butcher the abundant game, animals that soon appeared on the walls of limestone caves as the first expression of human art. They spread right across Europe, west across France and north as far as the British Isles.
As the climate deteriorated 25,000 years ago, the clan began its long migration south; eventually reaching Spain and founding what became a refuge for all humans during the coldest millennia of the last Ice Age. As the climate warmed, the scattered clan led the march back to the North to reclaim the once frozen lands. They reached the British Isles and left an indelible record in the limestone caves of Cheddar Gorge. In 1998, DNA was recovered from the famous skeleton known as Cheddar Man and our analysis showed that it belonged to the clan of Ursula. In a dramatic demonstration of genetic continuity, we found that a teacher at the local school, only a few hundred yards from the cave entrance, was clearly a member of the same clan.
Xenia (Greek for hospitable)
Of all the clans, Xenia's is the most mysterious. We know that she lived about 25,000 years ago on the cold and inhospitable European tundra at the eastern edge of the Black Sea. Although bleak and windy, the tundra was teeming with good things to eat as massive herds of bison and reindeer moved slowly over the plains, feeding on grass and mosses.
As the climate grew worse with the onset of the last Ice Age, Xenia's descendants left the rapidly cooling mountains and spread out to the East and West. They must have been prodigious travelers, because her clan can now be found not only all over Europe but also, intriguingly, in North America. This means that a few members of her clan must have traveled right across Asia and joined the first expeditions across the then dry Bering land bridge into the Americas.
Tara (Gaelic for rocky hill)
Tara lived in Tuscany about 17,000 years ago. At the time, Europe was in the grip of the last Ice Age and the only parts of the continent where life was possible were the lands bordering the Mediterranean. Then, the Tuscan hills were a very different place. No vines grew; no Bougainvillaea decorated the hillside farms. Instead, they were thickly forested with pine and birch. The streams held small trout and crayfish, which helped Tara to raise her family and held the pangs of hunger at bay when the men folk failed to kill a deer or wild boar.
As the Ice Age loosened its grip, Tara's descendants moved round the coast into France and joined the great band of hunters following the big game across the tundra that then covered Northern Europe. Eventually, Tara's descendants walked across the dry land that was to become the English Channel and moved right across to Ireland, from which Celtic kingdom the clan takes it name.
Helena (Greek for light)
Whether just by chance or by the guiding hand of natural selection we do not know, but Helena's clan has grown to become the most widespread and successful of the Seven Daughters of Eve. Her children have reached every shore, settled every forest and crossed every mountain range. Helena's descendants can be found from the Alps in the South to the Scottish Highlands and the Norwegian fjords in the North, and as far east as the Urals and the Russian steppes.
Helena was born about 20,000 years ago on the strip ofland that joins France and Spain, near what is now Perpignan. She belonged to a family of hunters, who harvested the rich oyster beds in the lagoons of the Camargue to supplement their diet of meat. Helena's clan arrived in Europe from the Middle East, pushing their way along the Mediterranean, constrained to the narrow strip of land that was still habitable.
Not long after she was born, the glaciers that covered the Pyrenees, which Helena could see on a clear day only thirty miles from her camp, began to draw back as, little by little, the summers grew warmer. Some of her clan moved south ofthe mountains, up the valley of the Ebro to the West to reach the lands of the Basque, where they remain to this day. The most adventurous of her children took advantage of the climatic improvements and journeyed ever northwards to join the great movement of hunters across the plains of France. We know that they reached England around 12,000 years ago because DNA recovered from a young male skeleton found in Gough's Cave in Somerset shows that he too belonged to the clan of Helena.
Katrine (Greek for pure)
One day in the Autumn of 1991, two hikers who were enjoying a late summer holiday in the Alps, strayed off the main path and crossed the head of a small glacier. To their astonishment they saw, protruding from the ice, the head and upper torso of a man. At first, these were thought to be the remains of a music teacher who had been reported missing two years previously. However, the real importance of this find was realized only when the renowned alpinist Reindhard Messner determined that the small axe found near the body was made not of steel but of copper. The remains were actually those of the Ice Man, a hunter who had lost his way and died of hypothermia some 5,000 years ago.
When DNA from a small fragment of one of the Ice Man's bones was analyzed, we saw clearly that Oetzi, as he became known (after the valley where he was discovered), belonged to the clan of Katrine. Katrine lived 15,000 years earlier on the southern slopes of the Alps that run gently down to the sea near Venice. She lived on ibex and chamois from the mountains, supplemented with whatever small mammals and roots could be found in the woods that covered the narrow plain.
As the glaciers retreated and snowfall became restricted to winter on the Alps, Katrine's children ventured farther north into the valleys to hunt the marmot and the ibex. As it became warmer still, her descendants crossed the great range and moved up the valley of the Rhine to meet the North Sea. Katrine's clan is still found in the Alps, five thousand years after the Ice Man had lived, as well as over much of northern Europe.
Velda (Scandinavian for ruler)
Velda lived in Spain 17,000 years ago. Her ancestors had journeyed to this warm refuge many years before, but she was still too young to have encountered the last of the Neanderthals, who had disappeared from Iberia around ten thousand years earlier.
Velda's descendants shared their lands with the clan of Ursula, and competition for the meager resources that this mountainous land had to spare caused conflict between them. However, once the weather began to warm up, the old quarrels were forgotten and children of both clans could travel to new lands. Velda's descendants pushed north around the strip of land to the west of the Pyrenees into the plains of Gascony, and slowly over the next three centuries across France and into Britain. Eventually, a few members of her clan edged up the still frozen seaboard of Norway to the far north where they joined pioneers from Arctic Russia to become the Lapps, or Saami, of northern Finland and Norway, where they can still be found today.
Jasmine (Persian for flower)
While the other six clan mothers had to endure the hardships of the European Ice Age whilst bringing up their children, Jasmine was enjoying the comparative warmth of the Syrian savannah. Life was good. The spring and autumn migrations of gazelle passed through her territory and provided a supply of meat that could be dried and made to last. There were sand grouse to trap and abundant small game on the open grasslands. In fact, so reliable was the food supply that it became unnecessary to move from one temporary camp to another.
Jasmine was born into one of the first semi-penname camps that would eventually become the villages and towns most of us inhabit today. This domestic stability removed the pressure to spend all their time searching for food allowing them time to experiment. A man from a settlement nearby had found that the dried seeds of wild grass could be collected without much trouble and made a tasty alternative to dried gazelle. Someone else found some larger grains on a distant hill and spilled a few at the campsite. After the rains, he noticed that the seeds had grown into new plants and that they, too, held the large grains of their parents. Thus began the greatest shift in human evolution, the invention of agriculture. As wheat replaced meat, the population began to grow. Brave souls captured wild sheep and cattle and fed them with the new crop. Slowly, over years of selective breeding, these animals lost their savage tendencies and settled into a life of domestication, where they remain to this day. Before long, it was getting crowded and so it became the custom that the second sons moved away to establish their own fannsteads. Slowly at first, the children of Jasmine spread across Anatolia and into Greece. Then the groups split up: one forced its way across the Balkans and up the fertile valleys of the Danube and the Elbe, tilling and planting in the fine soil founded by the wind blown particles ground from the mountains by the retreating glaciers. The other band took to the sea, edging round the Mediterranean as far as Spain and Portugal.
However, they were not arrivals in an empty land. At every turn they encountered the hunter gatherers. At first, these meetings were uneasy confrontations, but as the hunters realised that they faced no competition from the much slower fanners, the process of integration began. Little by little, the proud hunters abandoned their nomadic ways for the comparative comfort and security of life on the farm - a way of life brought to Europe by the children of Jasmine."