The author is grateful to the following publishers for permission to reprint brief extracts: Harvard University Press for four extracts from Nancy Wexler's article in The Code of Codes, edited by D. Kevles and R. Hood (pp. 62-9); Aurum Press for an extract from The Gene Hunters by William Cookson (p. 78); Macmillan Press for extracts from Philosophical Essays by A. J. Ayer (p. 338) and What Remains to Be Discovered by J. Maddox (p. 194); W. H. Freeman for extracts from The Narrow Roads of Gene Land by W. D. Hamilton (p. 131); Oxford University Press for extracts from The Selfish Gene by Richard Dawkins (p. 122) and Fatal Protein by Rosalind Ridley and Harry Baker (p. 285); Weidenfeld and Nicolson for an extract from One Renegade Cell by Robert Weinberg (p. 237). The author has made every effort to obtain permission for all other extracts from published work reprinted in this book. This book was originally published in Great Britain in 1999 by Fourth Estate Limited. GENOME. Copyright © 1999 by Matt Ridley. All rights reserved. Printed in the United States of America. No part of this book may be used or reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information address HarperCollins Publishers, Inc., 10 East 53rd Street, New York, NY 10022. HarperCollins books may be purchased for educational, business, or sales promotional use. For information please write: Special Markets Department, HarperCollins Publishers, Inc., 10 East 53rd Street, New York, NY 10022. FIRST U.S. EDITION Library of Congress Cataloging-in-Publication Data Ridley, Matt Genome: the autobiography of a species in 23 chapters/Matt Ridley. p. cm. Includes bibliographical references and index. ISBN 0-06-019497-9 1. Human genome Popular works. 2. Human genetics Popular works. I. Title. QH431.R475 2000 599.93'5—dc21 99-40933 00 01 02 03 04 RRD 10 9 8 7 6 5 4 3 2 1 CONTENTS Acknowledgements l Preface 3 1 Life 11 2 Species 23 3 History 38 4 Fate 54 5 Environment 65 6 Intelligence 76 7 Instinct 91 X and Y Conflict 107 8 Self-interest 122 9 Disease 136 10 Stress 147 11 Personality 161 12 Self-Assembly 173 13 Pre-History 185 14 Immortality 195 15 Sex 206 16 Memory 219 17 Death 231 18 Cures 243 19 Prevention 258 20 Politics 271 21 Eugenics 286 22 Free Will 301 Bibliography and Notes 314 Index 337 ALSO BY MATT RIDLEY The Red Queen: Sex and the Evolution of Human Nature The Origins of Virtue: Human Instincts and the Evolution of Cooperation ACKNOWLEDGEMENTS In writing this book, I have disturbed, interrupted, interrogated, emailed and corresponded with a great variety of people, yet I have never once met anything but patience and politeness. I cannot thank everybody by name, but I would like to record my great debts of gratitude to the following: Bill Amos, Rosalind Arden, Christopher Badcock, Rosa Beddington, David Bendey, Ray Blanchard, Sam Brittan, John Burn, Francis Crick, Gerhard Cristofori, Paul Davies, Barry Dickson, Richard Durbin, Jim Edwardson, Myrna Gopnik, Anthony Gottlieb, Dean Hamer, Nick Hastie, Brett Holland, Tony Ingram, Mary James, Harmke Kamminga, Terence Kealey, Arnold Levine, Colin Merritt, Geoffrey Miller, Graeme Mitchison, Anders Moller, Oliver Morton, Kim Nasmyth, Sasha Norris, Mark Pagel, Rose Paterson, David Penny, Marion Petrie, Steven Pinker, Robert Plomin, Anthony Poole, Christine Rees, Janet Rossant, Mark Ridley, Robert Sapolsky, Tom Shakespeare, Ancino Silva, Lee Silver, Tom Strachan, John Sulston, Tim Tully, Thomas Vogt, Jim Watson, Eric Wieschaus and Ian Wilmut. Special thanks to all my colleagues at the International Centre for Life, where we have been trying to bring the genome to life. Without the day-to-day interest and support from them in matters biological 2 GENOME and genetic, I doubt I could have written this book. They are Alastair Balls, John Burn, Linda Conlon, Ian Fells, Irene Nyguist, Neil Sulli­ van, Elspeth Wills and many others. Parts of two chapters first appeared in newspaper columns and magazine articles. I am grateful to Charles Moore of the Daily Tele­ graph and David Goodhart of Prospect for publishing them. My agent, Felicity Bryan, has been enthusiasm personified throughout. Three editors had more faith in this book when it was just a proposal than (I now admit) I did: Christopher Potter, Marion Manneker and Maarten Carbo. But to one person I give deeper and more heartfelt gratitude than to all the rest put together: my wife, Anya Hurlbert. PREFACE The human genome — the complete set of human genes - comes packaged in twenty-three separate pairs of chromosomes. Of these, twenty-two pairs are numbered in approximate order of size, from the largest (number 1) to the smallest (number 22), while the remain­ ing pair consists of the sex chromosomes: two large X chromosomes in women, one X and one small Y in men. In size, the X comes between chromosomes 7 and 8, whereas the Y is the smallest. The number 23 is of no significance. Many species, including our closest relatives among the apes, have more chromosomes, and many have fewer. Nor do genes of similar function and type neces­ sarily cluster on the same chromosome. So a few years ago, leaning over a lap-top computer talking to David Haig, an evolutionary biologist, I was slightly startled to hear him say that chromosome 19 was his favourite chromosome. It has all sorts of mischievous genes on it, he explained. I had never thought of chromosomes as having personalities before. They are, after all, merely arbitrary collections of genes. But Haig's chance remark planted an idea in my head and I could not get it out. Why not try to tell the unfolding story of the human genome, now being discovered in detail for the first time, chromosome by chromosome, by picking a gene from 4 GENOME each chromosome to fit the story as it is told? Primo Levi did something similar with the periodic table of the elements in his autobiographical short stories. He related each chapter of his life to an element, one that he had had some contact with during the period he was describing. I began to think about the human genome as a sort of autobiog­ raphy in its own right — a record, written in 'genetish', of all the vicissitudes and inventions that had characterised the history of our species and its ancestors since the very dawn of life. There are genes that have not changed much since the very first single-celled creatures populated the primeval ooze. There are genes that were developed when our ancestors were worm-like. There are genes that must have first appeared when our ancestors were fish. There are genes that exist in their present form only because of recent epi­ demics of disease. And there are genes that can be used to write the history of human migrations in the last few thousand years. From four billion years ago to just a few hundred years ago, the genome has been a sort of autobiography for our species, recording the important events as they occurred. I wrote down a list of the twenty-three chromosomes and next to each I began to list themes of human nature. Gradually and painstakingly I began to find genes that were emblematic of my story. There were frequent frustrations when I could not find a suitable gene, or when I found the ideal gene and it was on the wrong chromosome. There was the puzzle of what to do with the X and Y chromosomes, which I have placed after chromosome 7, as befits the X chromosome's size. You now know why the last chapter of a book that boasts in its subtitle that it has twenty-three chapters is called Chapter 22. It is, at first glance, a most misleading thing that I have done. I may seem to be implying that chromosome 1 came first, which it did not. I may seem to imply that chromosome 11 is exclusively concerned with human personality, which it is not. There are prob­ ably 60,000—80,000 genes in the human genome and I could not tell you about all of them, partly because fewer than 8,000 have PREFACE 5 been found (though the number is growing by several hundred a month) and partly because the great majority of them are tedious biochemical middle managers. But what I can give you is a coherent glimpse of the whole: a whistle-stop tour of some of the more interesting sites in the genome and what they tell us about ourselves. For we, this lucky generation, will be the first to read the book that is the genome. Being able to read the genome will tell us more about our origins, our evolution, our nature and our minds than all the efforts of science to date. It will revolutionise anthropology, psychology, medicine, palaeontology and virtually every other science. This is not to claim that everything is in the genes, or that genes matter more than other factors. Clearly, they do not. But they matter, that is for sure. This is not a book about the Human Genome Project — about mapping and sequencing techniques - but a book about what that project has found. Some time in the year 2000, we shall probably have a rough first draft of the complete human genome. In just a few short years we will have moved from knowing almost nothing about our genes to knowing everything. I genuinely believe that we are living through the greatest intellectual moment in history.