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a miniature vacuum cleaner which I had rigged up for collecting the powdered dentine into a sterile
test tube. With this in place, I began to drill out the dentine, carefully moving the bit up and down
inside the tooth, pulling back as soon as I felt it touch the hard enamel on the other side. All the
time the vacuum line was transferring the creamy white powder into the test tube and collecting it
in a small pile at the bottom. Within a few minutes, I had completely excavated the inside of the
tooth. In the test tube lay precisely 208 milligrams of dentine powder from the Old Stone Age.
Within two weeks, and in ways that we will cover later, I had recovered enough DNA from the
Cheddar tooth to read the genetic fingerprint of its original owner – a young man whose pattern of
life was so utterly different from our own that it is hard to imagine any possible connection
between him and ourselves. And yet the fragment of his DNA that I had recovered from his tooth is
exactly the same in every detail as that of thousands of people living in the Isles today. His
descendants are with us still – and you may well be one of them.
It is now almost ten years since the day I drilled into the Cheddar tooth, but the moment is still
vivid in my memory. It was not the first time I had attempted to recover DNA from ancient
skeletons, but it was the most scary. This was a priceless and irreplaceable specimen. But what
was I, a trained geneticist, doing drilling into the tooth in the first place? I had spent the early part
of my career researching the causes of inherited diseases, mainly those affecting the skeleton –
hence the location of my laboratory in Oxford’s Institute of Molecular Medicine. This research had
led to the discovery of the genes involved in giving strength to bones – the genes which coded for
bone collagen – and to the mutations in the collagen genes which caused these often devastating
diseases.
It was only a chance introduction to an archaeologist, Robert Hedges, who runs the carbondating
lab in Oxford, that got me involved in the human past at all. Robert wanted to see if he could
get more from the bone samples coming to his laboratory for carbon-dating than merely finding out
how old they were. Carbon-dating relies on counting the tiny number of radioactive carbon atoms
that lie in the collagen of ancient organic remains. As these atoms decay with time, the fewer there
are, the older the sample. Robert got in touch, having heard about my research on the genetics of
bone collagen, and we started to plan what we might be able to do with these old bones. To cut a
long story short, within two years we had worked out a way of recovering DNA from human and
animal bones that were hundreds or even thousands of years old.
Being the first laboratory in the world to do this, we were well placed to receive exciting
samples from all over the world. Over the years we have had bits of Neanderthals; Oetzi, the
famous Iceman from the Alps; various claimants to being Anastasia, the last of the Romanovs; a
selection of dead poets and statesmen; not to mention the odd piece of Yeti skin. To put the DNA
results from this eclectic collection into some form of context, I began a programme of collecting
DNA samples from living people. For instance, although it was wonderful to be able to get DNA
from the 5,000-year-old Iceman, and that became a story in itself, it only became really interesting
when his DNA could be compared, and indeed matched, with someone living today. The
whereabouts of his modern descendants told us something about the movement of people throughout
Europe during the five millennia since his death.
Sometimes the DNA from modern people can solve long-standing riddles that had proved to be
intractable by any other means. The outstanding example of this was the research on the origin of
the Polynesians. These are the people who live on the far-flung islands of the Pacific. All the