Blood of the Isles (15 page)

This is how I got to know the data. Thanks to a mapping program written by a colleague, I could quickly place any selection of DNA sequences on a map of the Isles. As I did this I soon noticed that some DNA sequences were found in all parts of the Isles, while others were very localized. For instance, I had found one particular mDNA sequence in the clan of Tara four times in Skye, once in Lewis in the Western Isles and once in Glasgow – and nowhere else in the world. When I looked up in my records where on Skye the four people lived, I saw they came from different parts of the island. But all traced their maternal ancestry back to the Isle of Rona.

Drive to the north end of Skye past the eroded cliffs and pinnacles of Trotternish, high above the sea, and Rona is the low rocky island on your right, lying 5 miles offshore. It looks as if it is connected to the longer, higher island of Raasay to the south, but it is not. A hidden sea channel separates the two islands. Rona is deserted now, but once held a few crofting families who fished in the dark blue seas. Their houses have been abandoned and only the lighthouse, white against the rocks, is visible from Skye.

What must have happened on Rona to account for the unusual DNA I had found on Skye was a mutation, a slight change in the DNA of one of the ancestors. Silent, unnoticed and with no effect at all on the woman in whom this event had occurred, just one DNA base, one bead on the chain, had changed. The new sequence was unique, never seen before in the history of the world. If this woman had been childless or had only sons, it would have died with her. No one would ever know it had been created. But she must have had children, and at least one of her children must have been a girl for her mDNA to be passed on. Through this girl, or her descendants, this new sequence left the island of Rona and found a home on nearby Skye, where it still remains. From there, perhaps one of the daughters in the next generation went to live on Lewis while another travelled down to Glasgow. I cannot tell exactly when this happened, but the journeys have been recorded by the genes of the descendants. I have not found this particular sequence of DNA letters anywhere else. Nor has anyone as far as I am aware. That doesn’t mean it isn’t there in other parts of Scotland, or Ireland, or Wales, or England. Just that we haven’t found it. That is always the way, and always will be. We will never know everything there is to know about this new gene and what happened to it. We can only piece together something of its journey from the scraps of information that have both survived to the present day and that we have found in the cells of people we have tested.

This is a little story of one particular gene, a new version that has changed very slightly. If we ever do come across it
again in the future, we will know it has travelled from Rona. It is a fragment, like a piece of pottery or a flint tool, and just as reliant on the twin necessities of survival and discovery as any archaeological remains. This is how I would build the genetic history of the Isles, by sifting through the thousands of fragments, trying to make sense of them. I would treat them as if they were the scattered shards of broken pottery and do what I could to understand what they meant. This was the point at which I decided to become a genetic archaeologist. I would work with fragments of DNA, perfectly preserved in the bodies of descendants, to reconstruct the travels of their ancestors with the same discipline that an archaeologist would use when excavating a site. Collect, examine, record, compare, interpret. In my mind’s eye, even though they were in reality stored on my computer, I began to think of them as, literally, a pile of fragments, pottery perhaps or maybe coins. Yes, coins would be an even better metaphor. Through Chris Howgego, a friend and colleague from Oxford, I had been allowed to examine the Ashmolean Museum’s collection of ancient gold coins from Britain. Many are over 2,000 years old but still fresh and lustrous, stamped with the image of an ancient tribal king or the stylized outline of a horse, a chariot wheel or an ear of wheat. I would set out to use the genes to interpret the past, just as Chris Howgego used his coins.

Of course they would tell very different stories. Coins and genes are not the same, but neither are they so very different. Both have to obey the rules of survival and discovery and, in the case of gold coins at least, both had been
preserved virtually intact. Both bore inscriptions, either the name of a king or the sequence of a piece of DNA. A coin from a distant land discovered in Britain is a witness to a journey made, just as much as a fragment of mDNA must have made its way to the Isles at some time in the past in the cells of an ancestor. Coins have one thing that is conspicuously lacking in DNA and that is a date. Though the Iron Age coins in the Ashmolean Museum do not have a calendar date impressed on them, their date of manufacture can be worked out from the tribal chief whose image or inscription is on the coin. For example, several are inscribed with the letters CVNO, denoting that they were minted during the reign of Cunobelinus, King of the Catuvellauni some time between 60 and 41
BC
.

With DNA we are not quite so fortunate. It does not bear a date stamp, but there is information on time depth to be had along the same lines that we have already used when working out how long ago the clan mothers lived. We can get an idea, though only an approximate one, of how long a group of mDNA or Y-chromosome ‘gene-coins’ has been in a location by seeing how they differ from one another. But it can be tricky, as we will find out.

I decided to excavate my first pile of ‘gene-coins’ from the results of the Genetic Atlas Project and I would begin with the mDNA, those fragments of history that have been passed down in the bodies of women. To begin with I did what anybody would do with a pile of gene-coins. I counted them. I had a total of 3,686. I imagined a large outline map of the Isles spread out in front of me ready for me to place each gene-coin in its correct location. But before distributing
them, I sorted the large pile out into smaller groups of different types, depending on their clan. Once I decided on that course, the way forward became a little bit easier to imagine. I could now abandon the manacles of conventional statistical analysis and approach my reconstruction of past events as a genetic archaeologist. That meant, for one thing, that I could give up trying to know everything, and also stop pretending that giving answers to sixteen decimal places means anything at all.

Historians and archaeologists realized this a long time ago and make do with what they have, while being on the lookout for new material. Geneticists do not naturally think like that. They are not natural storytellers. If a geneticist does not get a watertight answer after an experiment or a survey of some kind, he or she will go back to the drawing board rather than risk saying anything that might be shown later to be wrong. If it is a survey and 1,000 samples have failed to produce a statistically significant result, our training tells us to say nothing and increase the number to 10,000, and if that doesn’t work to 100,000. Having reinvented myself as a genetic archaeologist, I was free to do my best to tell the story of the Isles in my own way with what data are available. The account will never be complete, even if I were to double or quadruple the number of DNA samples. Also, even though I knew perfectly well that I would have to do the actual operations on my computer, the vision of the gene-coins as tangible objects which could be picked up and examined and then moved into position on a map was unexpectedly reassuring. I had rescued the project from the number-crunchers.

What did the pile of gene-coins look like? It was easy to decide on how to create the different piles. I would arrange them according to their maternal clan. I can tell the maternal clan of one mDNA sequence from the combination of mutations that it has. If I see the combination 126, 294 I know I am dealing with a member of Tara’s clan. If the sequence contains 256, 270 this is the mDNA of an Ursulan, and so on. These mutations became the inscriptions on the gene-coins and the portraits changed from tribal chieftains to the rough profiles of the seven matriarchs, Ursula, Xenia, Helena, Velda, Tara, Katrine or Jasmine.

In my mind the action moved to a baize-covered table. I soon sorted the large pile into smaller ones, one for each maternal clan. In the largest of these clan piles I had 1,799 gene-coins with the profile of Helena. The next biggest was the 434 in Jasmine’s pile, followed in sequence by 384 Tarans, 284 Katrines, 264 Xenias, 207 Ursulans and lastly 116 Veldans.

But there were still a lot of gene-coins that remained in the unattributed pile. I looked at the portraits and the inscriptions. These were of other matriarchs, not the Seven Daughters of Eve, but ones I still recognized. The most common were the gene-coins belonging to the matriarch Ulrike. There were 101 in all, only a few short of the Veldans. I had not included Ulrike as one of the what would then have been Eight Daughters of Eve because, in the research in Europe, the clan of Ulrike was considerably less frequent than the other seven in the regions we had surveyed, which were mainly the southern and western
parts. As more information came in from Scandinavia and eastern Europe, we saw more and more members of Ulrike’s clan. I’ve wondered since whether Ulrike should be promoted, as it were, into the select group of clan mothers.

But even with the Ulrikans now separated from the rest, there were still quite a few gene-coins in the pile. They were an exotic collection, from matriarchs all over the world. I stacked them together for now. There were ninety-seven in all. These, then, were the fragments with which to build the genetic history as told by women.

On the male side I had 2,414 Y-chromosome gene-coins from the Genetic Atlas Project and began to sort these into different piles according to their clans. Though the genetic details were displayed in a different form, the principle was the same. Each clan, of which there were five major ones in the Isles, traced a direct patrilineal line of descent right back to a common ancestor, the man who had founded the clan. In the Isles, these were the clans of Oisin (pronounced Osheen), Wodan, Sigurd, Eshu and Re.

Even though I knew full well that the gene-coins did not exist in reality, the concept gave me a lot of confidence. I began to relish the prospect of trying my best to interpret them and what they told of the past, rather than despairing as I had been up to then. Now, at last, I was mentally ready to launch into the final stages of the project. It was now as an archaeologist that I settled down to explore the Blood of the Isles.

The Irish landscape has often been compared to a bowl. A broad central limestone plain dotted by lakes and peat bogs and drained by sluggish rivers is surrounded by coastal ranges of hills and mountains. This upland barrier is only breached to any significant extent around the capital, Dublin. The total land area is 32,000 square miles (26,600 in the Republic and 5,400 in Ulster). The highest peaks, Lugnaquillia (926 metres) in the Wicklow Mountains south of the capital and Carrantuohill (1,041 metres) in Kerry, are on a par with the tallest mountains in Wales and England but well below many of the highest peaks in Scotland. In the west, the mountains thrust out long fingers into the Atlantic Ocean, creating a series of deep bays between, many of them now flooded river valleys. In the far south-west these rocky fingers are formed by parallel folds of sedimentary old red sandstone, like parts of northern Scotland, but further north in Galway, Mayo and Donegal, as well as in the Wicklow Mountains to the east, the rock is
granite, the weathered remnants of once-molten magma forced to the surface by ancient movements of the earth’s crust. On the eastern coast, facing Britain, the coastline is more orderly, without the drama or the dangers of the stormbound west.

As in the rest of the Isles, the landscape has been sculpted by ice. During the last glaciations, the ice covered only the northern half, extending as far as a line between Limerick in the west and Dublin in the east, but earlier Ice Ages enveloped the entire land in their frozen grip. The scouring of the central lowland plateau created the bedrock upon which the great peat bogs later grew and which, later still, provided the main supply of fuel for generations of rural households. The ice also ground the limestone base into a powder which formed the most important element of Irish soil. Without the glacial limestone powder to enrich it, the soil, made up of the weathering from older rocks like quartzite, granite and shale, would be infertile and unproductive like so much of the Scottish Highlands. But limestone gives it life, and thanks to this essential enrichment, and to the high rainfall, Ireland has thrived on its green pastures. Without the limestone, Ireland would not be the Emerald Isle, but the Brown.

On the ‘Irish History’ shelves of any high-street bookshop, the titles on display are dominated by the political struggles of the last hundred years. Books abound on the Easter Rising of 1916, alongside biographies of Michael Collins, Eamon de Valera and other heroes in the struggle for independence from Britain. A struggle which continues to this day, as Republicans strive to unite Ireland into the
single nation it once was. As I write, in 2007, the intensity of the cycle of violence and recrimination has all but disappeared. Earlier this year, in a political accord no one thought possible even six months before, the leaders of Sinn Fein and the Democratic Unionist Party, the two most polarised political opposites in Northern Ireland, agreed to share power in a devolved assembly. Peace, for the time being at least, has been restored. The roots of this struggle go back a very long way and, though
Blood of the Isles
is certainly not a political history, it is as well to be aware of events which may have had some influence on the genetic patterns we are setting out to interpret.

The current struggles for Irish political unity and independence are but the latest stages in a chain of events that began over 800 years ago when, in the autumn of 1171, Henry II, the Anglo-Norman king of England, landed in Ireland to make sure that it did not become a rival Norman state to his own. Five years earlier, the ambitious Richard de Clare, Earl of Pembroke, himself an Anglo-Norman, had responded to an invitation by one of the numerous Irish kings, Dermot MacMurrough, whose lands in the Leinster had been seized by the High King, Rory O’Connor. This was a classic situation, seen many times before and since, where an invitation by a dispossessed or threatened king is used as a cover for invasion. De Clare, whose sobriquet ‘Strongbow’ adequately describes his attitude to conquest, seized the chance and established a secure foothold in Wexford and the south-east part of Ireland which faced his base in Pembroke, only 40 miles by sea. His military campaigns were extremely effective,
thanks largely to the superior weapons he brought across. Heavily armoured knights, especially when mounted on horseback, easily overcome the local opposition armed only with light bows and spears.