the seven daughters of eve_ the science - bryan sykes

[...]... are the executives of the body They are the enzymes which digest your food and run your metabolism; they are the hormones that coordinate what is happening in different parts of your body They are the collagens of the skin and bone, and the haemoglobins of the blood They are the antibodies that fight off infection In other words, they do everything Some are enormous molecules, some are tiny What they... what they did During fertilization, one set of these strange threads seemed to come from the father’s sperm and another set from the mother’s egg This was just what had been predicted by the man universally acknowledged as the father of genetics, Gregor Mendel, a monk in the town of Brno in the Czech republic who laid the foundation for the whole of genetics from his experimental breeding of peas in the. .. discs which are either black or white Every year, one disc, chosen at random, is changed to the other colour When the tribe splits into two groups, each group takes with it a copy of the pole with the discs in their current order The following year they each make one of the random changes to the discs The next year they make another, the next year another and so on, continuing the custom of one random... crystalline fibres of purified DNA and bombarding them with X-rays As the X-rays entered the DNA, most went straight through and out the other side But a few collided with the atoms in the molecular structure and bounced off to one side where they were detected by sheets of X-ray film – the same kind of film that hospital radiographers still use to get an image of a fractured bone The deflected X-rays made... one at a time The lines on the tree in Figure 2 are reconstructions of the relationships among these sixteen people, worked out from the differences in their mitochondrial DNA, the exact nature of which we will examine shortly But look for the moment at the tree itself The deep trunk at the top has four Africans at the tips, while the other deep trunk contains individuals from the rest of the world and... of the tribes with their poles and discs Then and only then would the nodes, the points on the tree from which two lines diverge, represent a real entity These would be the populations that existed before the splits, the proto-populations But is that what really happened in human evolution? For instance, in the European part of the tree, was there ever such a thing as the proto-Anglo-Italian population... again the metaphor of the tribe with its pole holding black and white discs But this time the pole is the mitochondrial DNA and the tribe that split in two is a person who has two children Both children inherit the same mitochondrial DNA, the genetic equivalent of the same pattern of discs on the pole When they have their own children they pass on the mitochondrial DNA to them, and so it goes on down the. .. at the bottom of the tube – a sort of grey sludge We guessed this was the remnants of the collagen and other proteins, bits of cells, maybe some fat – and, we hoped, a few molecules of DNA We decided to get rid of the protein using an enzyme Enzymes are the catalysts of biology, making things happen much more quickly than they otherwise would We chose an enzyme which digests protein, rather like the. .. ‘trunk’ and the rest of the world is another confirmation of the antiquity of Africa which the population trees also pick up The confusion in the ‘rest of the world’ trunk is confirmation of exactly what Arthur Mourant had in mind It is the mixing that marks the history of every living species’ Small wonder, then, that this diagram threw a very large spanner in the works of the population tree aficionados... argument about whether people exist or not They clearly do The other improvement is that the nodes on the tree are also real people and not some hypothetical concept like a ‘proto-population’ They represent the last common ancestors of the two people who branch off from that point The lines that connect the sixteen people on the diagram are drawn to reflect genetic differences between them in one very . York, NY 10110 Library of Congress Cataloging-in-Publication Data Sykes, Bryan. The seven daughters of Eve / Bryan Sykes. —1st American ed. p. cm. ISBN: 97 8-0 -3 9 3-3 231 4-6 1. Human population genetics