Free The Seven Daughters of Eve by Bryan Sykes Page B

Robinson had collected an example of every single coat variety that had ever been produced, and was interbreeding them to unravel the genetics. There were pure-white hamsters, lilac hamsters, hamsters with short dark fur and hamsters with long fine coats like an angora goat. So eminent was Mr Robinson in the world of Syrian hamsters that each time a new coat mutant was discovered, a pair would be sent to Ealing. We were looking at the world reference collection. To cap it all, he opened an old ‘Quality Street’ sweet tin and there inside, neatly stacked, were the dried skins of the original animals that had been sent to him. Martin Richards, who had made the trip along with Chris and myself, was so taken that he bought two hamsters from a pet shop in Ealing on the way home. He kept them in his flat for two years until they passed away. Of more immediate significance, we took away from Mr Robinson’s collection a few hairs taken from each strain.
    Mr Robinson had also given us the contact details of Syrian hamster breeders’ and owners’ clubs throughout the world, and Chris was about to write to them asking for hair samples when it occurred to us that this might not go down very well. We had already discovered that you needed quite a number of hairs to get out the DNA. Hamster hairs were very fine and tended to break off above the root. Although the animals didn’t mind a few hairs being plucked, they were likely to feel a little uncomfortable, and so were their owners, if we asked for substantial tufts. That’s when we realized we needed another source of DNA. We hit on what seemed at first a completely wild idea. We knew the DNA amplification reaction was exquisitely sensitive, which is why it had worked with the ancient DNA from the archaeological bones. Would there be enough hamster cells shed from the walls of the large intestine to survive in their droppings? Surely, not even the most devoted owner would begrudge parting with a few droppings for the cause of science. But would it work? There was only one way to find out – so next day Martin appeared with a fresh crop from his house guests. They were dried and shrivelled, rather like mouse droppings, and totally inoffensive. Even so, Chris used tweezers to pick them up and put them into a test tube. He boiled the droppings for a few minutes, spun down the sediment in a centrifuge and took a drop of the clear liquid into the DNA amplification reaction. It worked a treat.
    For the rest of the summer small packets arrived from hamster enthusiasts all over the world. With their characteristic rattle, we knew immediately what they were. We eventually got DNA from thirty-five hamsters, and it wasn’t long before Chris had sequenced the mitochondrial control region in all of them. They were all absolutely identical. So the story was true after all. All the pet hamsters in the world really do come from a single female. But more importantly for us, the control region had remained completely stable. From that very first hamster captured in the Syrian desert to its millions of great-great-great…great-grandchildren from every corner of the world, the control region DNA had been copied absolutely faithfully with not even a single mistake.
    It was an amazing thought. Going flat out, hamsters can manage four or five generations a year. At that rate there would have been time for at least two hundred and fifty hamster generations since 1930. Even though all thirty-five of our hamsters would not have traced independent maternal lines all the way back to 1930, the fact that there were absolutely no DNA sequence differences between any of them had to mean that the anxiety I had that mutations in the control region might be happening too quickly was unfounded. Quite the reverse, in fact: this was a very reliable region of DNA after all, not given to fickle fits of mutation that would make it impossible to trace over the hundreds of generations we