The Seven Daughters of Eve

by Bryan Sykes

  Within a month I was back in Chris’s office with the good news. There was plenty of DNA in the deer bone. Chris agreed that this was sufficiently good proof to allow me to sample the human material. On the table in his office he carefully laid out the actual remains of Cheddar Man, each one enclosed in a cardboard box and supported by cotton wool. The skull had its own made-to-measure wooden case, with foam rubber supporting the delicate reconstruction from a dozen or more fragments cemented together. I didn’t dare to touch it. Eventually we settled on the talus, the solid-looking bone of the big toe. Chris packed it into a small cardboard box and I took it back to the lab.

  Next day, I carefully drilled into the bone. What appeared from the outside to be solid bone was not. In no time I had punctured the thin shell of the cortex and was into the honeycombed interior. Black specks fell into the small pile of brownish bone powder from the drillings. These black bits certainly didn’t look like bone; most likely they were bits of soil that had found their way into the middle of the toe-bone through a crack. I picked them out one by one with watchmaker’s forceps and put them to one side. I had exactly 17.8 milligrams of Cheddar Man bone powder. It would just have to do; I didn’t want to make another hole. By the following day I knew it was not going to work. There was no sign of any DNA. The control experiments had worked perfectly. Bright orange fluorescent spots, indicating the presence of amplified DNA, were in all the positive controls. The blanks, always run at the same time with water and not bone extract to control for contamination, were all blank. And so was the extract of Cheddar Man’s toe. This was bitterly disappointing.

  I went back up to London to talk things over with Chris. We knew from the success with the animal bone that the environment of Gough’s Cave was good enough to preserve DNA for at least ten thousand years. Maybe the fact that the bones had been outside the cave for the best part of a century had something to do with it. Maybe the resin that was used to stabilize the bones had interfered with the DNA extraction. Or maybe there just wasn’t any DNA there at all. Just so that we could have a focus for our thoughts as much as anything, Chris brought the skull back into his office and laid it out on his desk once more. I don’t find it particularly easy to relate a skull to a living person but, as I looked at the pieces displayed on the desk, I began to imagine the flesh and the skin of the head building up on the reconstructed skull. As I write this it sounds distinctly macabre, but at the time it wasn’t in the least. In my imagination, these were no longer just lifeless fragments of bone but a real person. I had no clear impression of what he looked like – no idea whether he had black or fair hair, brown eyes or blue – but I did have a very strong feeling that this was a person. Strange, remote, from a far-off time, but a person none the less. What stories he could tell about his life, his family. I picked up the lower jaw and looked at his teeth, the teeth he used to crush hazelnuts and tear into the flesh of freshly caught deer. The enamel was worn down, but the teeth were not rotten. In fact, they looked pretty healthy compared to my own set, which are full of fillings. When I idly mentioned this to Chris he turned and said, ‘Well, if you think these are good, come and have a look at this.’ He led me out of his office and into the large room with the storage cabinets. We walked to a distant part of the room and Chris brought out another small wooden box. He opened it and inside, nestling on its bed of foam rubber, was the lower jaw of a younger male. The teeth were absolutely perfect. White, regular and with no sign of decay. They could have come straight out of a toothpaste ad. I imagined they must be only a few hundred years old at the most. But they were not. These were the teeth of a young man who lived more than twelve thousand years ago – over three thousand years before Cheddar Man – and whom Chris had excavated himself from Gough’s Cave in 1986.

  Back in the brightly lit office, the teeth looked even better. Could it be that, inside the teeth, the dentine and the pulp cavity would be much better protected even than the bone? Could the few molecules of DNA, which were all we needed to test our theory, be hiding inside the teeth encased in an unbroken shield of enamel? Even though we had failed with Cheddar Man’s toe, we agreed it would be worth a shot. But no-one had any experience of extracting DNA from teeth, especially teeth still embedded in the jaw, and there was no question of being allowed to remove them to make it easier. I promised to go away and devise a method of drilling into teeth in a way that did not mark the enamel and allowed them to remain in the jaw. If I could do that, then Chris would allow me to take a sample from the Gough’s Cave specimen.

  I was back within a fortnight, having practised on some teeth given to me by my dentist, Mr Miller. I had perfected a way of drilling into a molar tooth and getting the dentine out with the tooth still embedded in the jaw, and I brought with me some samples of my handiwork for Chris to inspect. After trying and rejecting a straightforward dental drill (the compressed air blew the powder all over the place) I had found a small modelling drill which had been recommended by a colleague at work and which I bought from an ironmonger on the Tottenham Court Road in London. It was just perfect for making the small entry hole just below the enamel. Once I had got inside the tooth, another, longer drill bit could be attached and wiggled to and fro, reducing the soft dentine to a fine powder. I rigged up a suction device and, using this, it was very easy to remove the powder from inside the tooth into a small test tube. The hole then only needed to be filled with a colour-matching cement and the tooth looked as good as new – as it were. And the dentine, at least in my trial teeth, was full of DNA.

  To avoid the ever-present possibility of contamination with modern DNA I needed to drill the teeth from the Cheddar fossils in my own laboratory, where we had recently installed a filtered-air clean room. We had bought it as a ready-made unit constructed for the silicon chip industry. The incoming air was filtered and maintained at a positive pressure, which meant that there was no chance of dust or flakes of skin getting into the room when you went in through the air lock. It was an expensive and elaborate precaution, but well worth it. So I had to take the jaw back with me to Oxford – which was a nightmare. I had come into London on the bus, and it was on the bus that I returned with this priceless and irreplaceable specimen in its box on the seat beside me. Every few seconds I would turn to make sure it was still there, trying to imagine what I could say if I lost it. Thank God, I didn’t; and by late afternoon it was safely locked away in the specimen cabinet back in Oxford.

  The next day I started the extraction. It couldn’t have gone better. The drill sank into the second molar easily, but not too easily – that would have been a sign of bad preservation – and there was a slight smell of burning in the air. This was the collagen being vaporized by the speed of the drill, a smell I used to hate during my own visits to the dentist but one I had now come to love as a sign that there was plenty of protein left in the specimen – and where there is protein there is usually DNA. When I switched on the suction pump, the pale cream powder came flying out of the tooth into the tube. There was lots of it – just under 200 milligrams. I took 50 milligrams, so as to leave plenty for a repeat, and started up the extraction process.

  By the following evening I knew I had mitochondrial DNA from the tooth. Over the next two weeks I read through the sequence, checked it again and confirmed it by a second extraction. I was looking at the DNA sequence of the oldest human fossil, by far, that had ever been successfully extracted anywhere in the world. But that wasn’t the most important thing. The crucial piece of information we were looking for was embedded in the details of the DNA sequence itself. Was this the same sequence as a thoroughly modern European, or was it an obscure relic that was now extinct?

  The answer was crystal clear. The ancient DNA from Gough’s Cave was also completely modern. The sequence lay at the centre of the largest of the seven mitochondrial clusters. It is by far the commonest sequence in modern Europe; and here we had found it in the tooth of a young man who had lived fully seven thousand years before the arrival of farming in
Britain. Here was the proof that this sequence, this cluster, and, by extension, the others of a similar estimated age were well and truly established in Europe long before the farmers. The Upper Palaeolithic gene pool had not been fatally diluted by the Middle Eastern farmers. There was more of the hunter in us than anyone had thought.

  Though I had got no further than drilling into his big toe, this was not the last encounter I had with Cheddar Man. We were re-introduced, so to speak, as part of a television documentary. Philip Priestley, an independent producer, was setting up a series of archaeology-based programmes for a west country TV station, and one of them was built around the excavation of a Saxon palace in Cheddar. By now our work on the genetic continuity between the Palaeolithic and the present day was reasonably well known, and it occurred to Philip that it would make good television if he could relate, through DNA, some of the present-day residents of the town with Cheddar Man himself. This seemed both fun and worthwhile; but I explained that we had already had a go at getting DNA from the Cheddar Man remains without success. If he could get permission from Chris Stringer, I was willing to try again, this time with the teeth, not the toe-bone, but only on condition that if nothing came of it we would not be filmed. I always work on that basis. I have seen too many programmes that begin with a big build-up anticipating a great scientific discovery at the finale, only to peter out in an inconclusive or unsuccessful experiment. So, with all the ground rules agreed, and after another nerve-racking journey on the bus, this time with an even more famous fossil in a box beside me, I drilled into Cheddar Man’s first molar.

  Out came the powder – not quite as clean as the earlier Gough’s Cave material, but in sufficient quantity for an extraction. We found enough DNA for a reasonable sequence and were not surprised when it fitted comfortably into one of the seven clusters. Philip, understandably nervous as the deadline for filming got closer, was delighted and immediately organized the second strand of the piece, the sampling of the Cheddar residents. The site of the Saxon palace, featured in another programme in the series, is in the grounds of the local secondary school, and it made good sense to approach the school to see if they would agree to their pupils taking part in the programme. By now we had refined our DNA sampling procedure. We no longer used blood samples; instead we found that a small brush rubbed gently against the inside of the cheek picks up enough cells from the surface to give us plenty of DNA. After a short visit to the school, we had twenty samples from the sixth form volunteers and some of the teachers. Knowing how often we had found Cheddar Man’s sequence in modern Britain, I reckoned there was a fifty–fifty chance of getting a close match in the twenty samples we had taken. Within four days we had the results. We knew the names, and (crucially, as it turned out) the ages of the volunteers. Philip was on the phone.

  ‘We’ve got a match,’ I told him.

  ‘Who is it?’ was his first question.

  This wasn’t part of the deal. While we had agreed to see if we could find a match among the twenty residents, I had not agreed to identify any individuals, for a very good reason. Although the children, and their parents, had signed forms consenting to have their DNA sampled and to take part in the television programme, I felt there was a risk that they might not have realized what they were letting themselves in for if the story broke in a big way. Though there is no way of knowing beforehand how big a story is going to become, the experience of Marie Moseley and the Iceman was an indication of its potential.

  At this point Philip became distinctly agitated. He thought the story would be worthless without an individual identification. He immediately faxed me a copy of the consent form, but as far as I could see it was just a standard release – not, in my opinion, sufficient as a basis on which to claim consent to a possible worldwide media intrusion into the life of a teenager. I checked our list of sequences against the names and ages of the volunteers. There was not one match but three: two exact matches with Cheddar Man, and one with a single mutation; and while the two exact matches were children, the close match was a teacher, in fact the head of history who was organizing the filming in the school, Adrian Targett. I made the decision that I would identify Adrian Targett but not the two children. As it turned out, it was one of the best decisions I ever made. Unknown to me, Philip and his publicity team had organized a public ‘reveal’ where Adrian Targett would be identified as Cheddar Man’s relative in front of the cameras and in the presence of a television news crew. They, too, were beginning to sense the potential magnitude of the story. The next day, when I went to the newsagent, I could not believe my eyes. The story of Adrian Targett and Cheddar Man was in all the papers: from the London Times to the tabloid Daily Star, there was Adrian on the front page, posing beside his famous fossil relative. I bought the lot.

  In the following days and weeks the story of Cheddar Man spread around the world. I met Adrian Targett on a TV chat show. He told me how one tabloid newspaper, famous for its pictures of topless women, had offered him a five-figure sum (so at least £10,000) to pose in a fur loincloth beside his ancient relative. Being a sensible man, conscious of his standing as a teacher, he declined. But it did make me wonder what the newspaper would have offered a teenage girl to wear the same outfit – or less. Even now, years later, people still remember the Cheddar Man story, if not always accurately. I was talking to an American audience in 2000 on something completely different when a woman asked me: ‘Are you the one who did the DNA from the Cheese Man?’ At the time, not surprisingly, I had a full postbag for weeks after the story broke. Many letters were complimentary, including a very well-informed one from the inmates of San Quentin gaol in California, who were keen to discuss the findings at the next meeting of their anthropology study group. But the one that stood out came from the secretary to Lord Bath. It turned out that Cheddar Caves are part of Lord Bath’s estate. Evidently he had read the story (though whether in the Times or the Daily Star I never discovered) and wanted to know if he too was related to Cheddar Man.

  Alexander Thynn, Lord Bath, is the owner of Longleat, one of the most beautiful houses in England. It is famous for the safari park in the grounds, where visitors can watch the famous Longleat lions and other dangerous animals from the alleged safety of a car. Lord Bath himself, affectionately referred to as the Loins of Longleat, is well known for his idiosyncratic personal life. In addition to a legitimate wife and children, he has a stable of what he calls his ‘wifelets’, many of whom live on the estate. This was definitely one to follow up, and the next weekend I was on the way to Wiltshire. I was led upstairs to the penthouse suite on the top floor of this magnificent Elizabethan house. Lord Bath himself, now in his sixties but with a youthful twinkle in his eye, was dressed in one of his collection of brightly coloured kaftans that bulged from a wardrobe close to an absolutely enormous wooden desk. The life clearly suited him. He poured out two large glasses of rosé from a tap on the wall as I went through the genetics with him. A few glasses later we got round to the test itself, and he brushed the inside of his cheek. During the course of the morning several other people passed through the penthouse, and each was encouraged to give a sample, which they cheerfully did. He was evidently very popular with his staff. By lunchtime we had half a dozen DNA brushes and it was time for me to leave.

  When we got the results back it came as no surprise that Lord Bath was not closely related to Cheddar Man. There was no particular reason why he should be. But his butler, Cuthbert, one of the other people who had given a sample during my visit to Longleat, was an exact match. At a stroke he could claim an ancestry which stretched back nine thousand years, making the five-hundred-year pedigree of the Thynns look distinctly nouveau. I asked Lord Bath how Cuthbert had received this piece of news. Had it made him reassess his attitude to the aristocracy? ‘Well,’ he replied with a smile, ‘he has been feeling very confident lately.’

  We had now done about as much as we could to establish our claim that the maternal ancestors of the majority of modern Europeans
were already living in Europe well before the arrival of farming. We could not say anything about other genes, only about mitochondrial DNA; but on this basis we had a clear picture of European prehistory, built up from both modern and fossil DNA, not of a massive replacement of the hunter–gatherers by the farmers but of a strong continuity back to the days of the Palaeolithic. There was only one of Cavalli-Sforza’s criticisms that we could not answer. Whatever way you look at it, mitochondrial DNA is only one gene and, as such, subject to statistical fluctuations that might make it unrepresentative of the human genetic legacy as a whole. I did not think this very likely; but what was needed to substantiate our version of European prehistory was confirmation from another gene altogether.