Genetics of Original Sin Read online

  Genetics of Original Sin

  Published in association with Éditions Odile Jacob for the

  purpose of bringing new and innovative books to English-

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  improve our understanding of society, the discussions

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  current debate of ideas.

  Genetics of

  Original Sin

  The Impact of Natural Selection

  on the Future of Humanity

  CHRISTIAN DE DUVE

  WITH NEIL PATTERSON

  FOREWORD BY

  EDWARD O. WILSON

  Yale

  UNIVERSITY PRESS

  New Haven & London

  Éditions Odile Jacob

  Paris

  Published with assistance from the foundation established in memory of

  Philip Hamilton McMillan of the Class of 1894, Yale College.

  Translated from Génétique du péché originel, by Christian de Duve,

  published by Éditions Odile Jacob in 2009.

  Copyright Odile Jacob, 2009;

  ISBN 978-2-7381-2218-6.

  English-language translation copyright © 2010 by Yale University.

  All rights reserved.

  This book may not be reproduced, in whole or in part, including illustrations, in any

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  Set in Minion type by Integrated Publishing Solutions.

  Printed in the United States of America.

  Library of Congress Cataloging-in-Publication Data

  De Duve, Christian.

  [Génétique du péché originel. English]

  Genetics of original sin : the impact of natural selection on the future of humanity /

  Christian de Duve with Neil Patterson; foreword by Edward O. Wilson.

  p. cm.

  Includes index.

  ISBN 978-0-300-16507-4 (clothbound : alk. paper) 1. Life—Origin. 2. Life (Biology) 3. Evolution (Biology) 4. Natural selection. 5. Genetics.6. Twenty-first century—Forecasts. I. Patterson, Neil. II. Title.

  QH325.D41313 2010

  576.8—dc22

  2010029161

  A catalogue record for this book is available from the British Library.

  This paper meets the requirements of ANSI/NISO Z39.48–1992 (Permanence of Paper).

  10 9 8 7 6 5 4 3 2 1

  ALSO BY CHRISTIAN DE DUVE

  A Guided Tour of the Living Cell, Scientific American Books (New York: W. H. Freeman, 1984)

  Blueprint for a Cell: The Nature and Origin of Life (Burlington, NC: Neil Patterson, Publishers, 1991)

  Vital Dust: Life as a Cosmic Imperative (New York: Basic Books, 1995)

  Life Evolving: Molecules, Mind, and Meaning (New York: Oxford University Press, 2002)

  Singularities: Landmarks on the Pathways of Life (New York: Cambridge University Press, 2005)

  To Janine

  “And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat.”

  —GENESIS 3:6

  Contents

  Foreword by Edward O. Wilson

  Preface

  Acknowledgments

  Introduction

  Part I. The History of Life on Earth

  Chapter 1. The Unity of Life

  Advancing knowledge has swept away “centrisms”

  Earth has a history

  Life also has a history

  All living beings share a number of basic properties

  The history of life is written into molecular sequences

  Biological evolution is an established fact 11

  Opposition to evolution on religious grounds is widespread

  Chapter 2. The Origin of Life

  Life appeared on Earth shortly after the young planet had become physically able to harbor it

  The origin of life is not known, but the only scientifically acceptable hypothesis is that it arose naturally

  The building blocks of life arise spontaneously throughout the universe

  Earth formed a “cauldron” in which cosmic building blocks could interact

  The first steps in the origin of life were chemical in nature

  The appearance of RNA was a key step in the origin of life

  Chapter 3. The Evolution of Life

  Microbes have left few fossil vestiges but many other traces of their long duration on Earth

  Bacteria separated into two main groups

  Atmospheric oxygen was a major contribution of life to Earth

  The birth of eukaryotic cells inaugurated a new living world

  Endosymbiosis was a key phenomenon in the development of eukaryotes

  Protists are the ultimate champions of unicellularity

  Multicellularity allowed division of labor

  Born in water, plants were the first multicellular organisms to invade land

  The evolution of animals developed around the alimentary function

  Marine invertebrates inaugurated animal life

  Body segmentation opened the way to vertebrates

  Several distinct animal lineages moved from water to land

  Dinosaurs gave rise to birds and mammals

  Part II. The Mechanisms of Life

  Chapter 4. Metabolism

  Living cells are chemical factories

  Living cells extract the energy they need from their surroundings

  Thousands of specific catalysts are involved in metabolic reactions

  Metabolic pathways form networks of enormous complexity

  We are what our catalysts are

  The history of metabolism goes back to the earliest days of life

  Chapter 5. Reproduction

  Reproduction started with molecular replication

  With the appearance of cells, cell division was added to molecular replication in biological reproduction

  Multicellular beings reproduce by way of single mother cells

  The mother cell of multicellular beings arises from two parental cells by sexual reproduction

  Chromosome doubling caused by sexual reproduction is corrected by meiosis during gamete maturation

  Sexual reproduction is the laboratory of evolution

  Male and female gametes differ

  Plant reproduction involves spores

  Seeds and fruits harbor, until germination, the plant embryos issued from fertilized eggs

  Fungi also reproduce by way of spores

  In animals, parent mobility favors union between spermatozoa and oocytes

  The fertilized egg of vertebrates has always developed in an aqueous medium

  Chapter 6. Development

  The first accounts of embryological development were purely descriptive

  Experimental embryology began to decipher developmental mechanisms

  Development is ruled by transcriptional gene control

  Genes are organized by transcription into a hierarchy dominated by master genes

  Homeotic genes are master genes of central importance

  Evolution and development are intimately linked

  Chapter 7. Natural
Selection

  At the start lies heredity

  Artificial selection exploits the imperfections of heredity for defined purposes

  Malthus introduced the notion of the “struggle for life”

  Natural selection lets the “struggle for life” choose passively among the diversity created by the imperfections of heredity

  Natural selection acts under our very eyes

  The mutations subjected to natural selection are accidental events devoid of finality

  The role of chance in evolution is limited by stringent constraints

  Cases of optimizing selection are more frequent than long believed

  Evolution is largely molded by environmental conditions

  Certain evolutionary events could be potentially present in genomes and made manifest by favorable environmental conditions

  Chapter 8. Other Evolutionary Mechanisms

  Lamarck advocated the heredity of acquired characters

  DNA cannot be a vector of Lamarckian heredity

  Cases of Lamarckian heredity that do not involve DNA exist

  Genetic drift accompanies evolution without selection

  Self-organization could theoretically drive evolutionary events

  Were some key evolutionary steps guided by “intelligent design”?

  Part III. The Human Adventure

  Chapter 9. The Emergence of Humans

  Africa is the cradle of humankind

  They were not yet human, but they already made stone tools

  Prehumans started out of Africa for the first time some two million years ago

  A second wave of migrations started once again out of Africa

  The acquisition of language was a crucial step in hominization

  Cro-Magnon inaugurated modern humans

  What happened to the Neanderthals?

  Modern humans remain the only survivors from the adventure out of which they were born

  Chapter 10. Making the Human Brain

  The brain is constructed with neurons

  The cerebral cortex is the mysterious site of conscience

  It took six hundred million years for the animal brain to reach, in chimpanzees, a volume of 21.4 cubic inches

  In the human line, it took two to three million years for the brain volume to expand from 21.4 to 82.4 cubic inches

  The expansion of the human brain went through a number of successive plateaus

  Exponential neuron multiplication braked by anatomical constraints probably explains the sigmoid shape of the jumps of brain volume from one plateau to another

  Expansion of the human brain was limited by the size of the female pelvis and by the degree of immaturity at birth compatible with survival

  Chapter 11. Shaping Our Genes

  Hominization involved an astonishingly small number of individuals

  Hominization probably started with bipedalism, which was selectively advantageous in the local terrain

  Brain expansion dominated the second major stage of hominization

  The vagaries of environmental change probably guided the migrations that characterized the third stage of hominization

  Hominization: Chance or necessity? Summit or stage?

  Chapter 12. The Cost of Success

  Taking advantage of the powers of their brains, humans have proliferated beyond all measure and exploited a major part of the planet’s resources for their own benefit

  The history of humanity is a perpetual succession of wars and conflicts

  The inordinate evolutionary success of the human species has been acquired at the expense of a severe deterioration of living conditions on Earth

  If it continues in the same direction, humankind is headed for frightful ordeals, if not its own extinction

  Chapter 13. Original Sin

  Natural selection has indiscriminately privileged all the personal qualities that contribute to the immediate success of individuals

  Natural selection has privileged traits favoring cohesion within groups and hostility among different groups

  Natural selection has not privileged the foresight and wisdom needed for sacrificing immediate benefits for the sake of the future

  Original sin is none other than the fault written into human genes by natural selection

  The only possibility of redemption from the genetic original sin lies in the unique human ability to act against natural selection

  Part IV. The Challenges of the Future

  Chapter 14. Option 1: Do Nothing

  If nothing is done, humanity is headed for disaster

  The extinction of humankind, if it occurs, will be due, not to its failure, but to its success

  Could a “superhuman” species succeed the human species?

  Life has up to five billion years left before Earth becomes incapable of harboring it

  What could happen in a brain even more developed than the human brain?

  With the advent of humankind, evolution has reached a point where it is no longer a slave to natural selection

  Chapter 15. Option 2: Improve Our Genes

  Eugenics has become a dirty word

  Cloning opens the way to directed evolution

  What can cloning be used for?

  Human cloning provokes heated ethical debates

  Whatever happens, humanity will not be saved by cloning

  Chapter 16. Option 3: Rewire the Brain

  The wiring of the brain is an epigenetic phenomenon

  Education starts in the cradle

  Political and, especially, religious leaders are particularly well placed to propagate the recommendations the world needs

  Chapter 17. Option 4: Call on Religions

  Churches could play an exceptional role in saving humankind

  Religions are founded on beliefs, not on rational thought

  Many religions present themselves as defenders of the truth

  Religious doctrines have a major impact on ethical directives

  Hopes for a future life could hamper efforts in favor of present life

  Are religions to be fought, or can they be enlisted?

  Churches are engaged in many valuable activities

  What should we do?

  Ethics without doctrine is possible

  The dialogue between science and religion is desirable but difficult

  Religions, through their influence, and the sciences, through their knowledge, must urgently collaborate for the salvation of humanity

  Chapter 18. Option 5: Protect the Environment

  Protecting the environment is a very recent human concern

  Ecology has penetrated daily human life

  Ecology has become the source of major controversies

  Nuclear energy: pro or con?

  A basic discovery opened the way to revolutionary applications

  GMO: an acronym that ignites passions

  Are GMOs an assault against the sacredness of nature?

  Environmentalism has a crucial role to play

  Chapter 19. Option 6: Give Women a Chance

  Combativeness is primarily a male character

  In most civilizations, women are treated as inferior to men

  The social rise of women in the modern world is an encouraging change

  Chapter 20. Option 7: Control Population

  The crisis foreseen by Malthus has struck

  Culling is not a tolerable solution to the population problem

  One way or another, the birthrate must be reduced

  Limiting births needs to be encouraged

  Epilogue

  Index

  Foreword

  Christian de Duve has delivered a clear statement of why ours is the Century of Biology. If there is anything that science has taught us, it is that humanity is a biological species in a biological world. We originated here, grew up here, and are thoroughly adapted to this world in every fiber of our bodies and every neuronal circuit that thrums through our brain. In the fundamentals of structure a
nd development, we are not different from other organisms. And in the fine details of anatomy, we are close to our phylogenetic cousins, the great apes.

  With the smooth mastery acquired by a lifetime of distinguished scientific research, Professor de Duve guides the reader through 3.5 billion years of history that led from the earliest microbes to the present-day global biodiversity, including one of its most recent productions, the hominines—us. That said, let us not stress humanity’s humble origins to the extent of devaluating the immense achievement they represent. Humans are not only the smartest creatures ever evolved, exceeding by a wide margin the nearest competitors (great apes, elephants, cetaceans), we are also the only species to create culture based upon, with each piece potentially immortal, an infinitely creative language. We alone are capable of endless histories, fantasies, and instructions.

  We are nothing less than the mind of the biosphere. The achievement has been one of the major transitions of evolution, which together led from macromolecule to cell to eukaryotic cell to multicellular organism to society to the human-grade level of culture. However, whereas the earlier transitions occurred hundreds of millions or even billions of years ago, the last great transition, to the human level, occurred at best a few hundreds of thousands of years ago. It finally came to full flower in the Neolithic dawn a scant ten thousand years ago. Therein lies the dilemma identified by Professor de Duve. The earlier transitions occurred with agonizing slowness, while the human transition burst into the world as a biological supernova. Earth has not had time to adjust to this magnitude and abruptness—nor have we. The human condition is that depicted in the Star Wars movie trilogy: we have Paleolithic emotions upon which have been erected medieval institutions and godlike technology.

  Having explained this dilemma in clear detail, de Duve then invites the reader to join in finding the solution or, better, ensemble of solutions. The fundamental premise in his exercise is that a knowledge of humanity’s origins and nature, by scientists and the public alike, is necessary to find the correct solution. This is the transcendent goal, truly vital in nature, that requires the best that science, religion, and political leadership can put together.

  EDWARD O. WILSON

  Preface

  Life is the most extraordinary and perfected natural manifestation known to us. It has not ceased, ever since human beings have existed, to inspire awe and wonder. And now, for the first time in the history of humankind, knowledge and understanding have been added to those sentiments. This is a new situation. A mere four hundred years ago, it was not realised that blood flows round in a closed circuit or that living beings are made of cells; no microbe had been seen. Two hundred years ago, it was not known that infectious diseases are caused by invisible forms of life; there were no vaccines (except against smallpox, empirically introduced in 1796); no antibiotics; and it was not yet appreciated that all living beings, from microbes to humans, are part of a large family tree, born from a single root more than three and a half billion years ago. As recently as sixty years ago, knowledge of the fine structure of cells, their chemical constituents, and the fundamental mechanisms that underlie their activities was still in its infancy. Virtually nothing was known about DNA. The terms “double helix” and “genetic code” had not been invented. Today, in the space of just my own lifetime, all of these vital facts and processes have been clarified. It is no exaggeration to say that we understand life on Earth. Many details remain to be elucidated, but the essentials are known. What is probably the greatest leap in the history of knowledge has been accomplished. Such an illumination must not be kept to a few initiates.