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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
MENDEL IN THE KITCHEN
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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
MENDEL IN THE KITCHEN
A SCIENTIST’S VIEW OF GENETICALLY MODIFIED FOODS
Nina V. Fedoroff and Nancy Marie Brown
Joseph Henry Press
Washington, D.C.
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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
Joseph Henry Press
500 Fifth Street, NW Washington, DC 20001
The Joseph Henry Press, an imprint of the National Academies Press, was created with the goal of making books on science, technology, and health more widely available to professionals and the public. Joseph Henry was one of the founders of the National Academy of Sciences and a leader in early American science.
Any opinions, findings, conclusions, or recommendations expressed in this volume are those of the author and do not necessarily reflect the views of the National Academy of Sciences or its affiliated institutions.
Library of Congress Cataloging-in-Publication Data
Fedoroff, Nina.
Mendel in the kitchen : a scientist’s view of genetically modified foods / Nina V. Fedoroff and Nancy Marie Brown.
p. cm.
Includes bibliographical references (p. ) and index.
ISBN 0-309-09205-1 (cloth)
1. Genetically modified foods. 2. Plant genetic engineering. I. Brown, Nancy Marie. II. Title.
TP248.65.F66F436 2004
641.3—dc22
2004014040
Cover design by Van Nguyen. Carrot image © 1999 by Corbis Corporation.
Illustrations by Jeffery Mathison
Copyright 2004 by Nina V. Fedoroff and Nancy Marie Brown. All rights reserved.
Printed in the United States of America.
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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
CONTENTS
Illustrations
vii
Preface
ix
1
Against the Ways of Nature
1
2
The Wild and the Sown
23
3
The Power in the Earth
47
4
Genes and Species
67
5
Tinkering with Evolution
85
6
Making a Chimera
107
7
The Product or the Process
129
8
Is It Safe to Eat?
155
9
Poisoned Rats or Poisoned Wells
177
10
The Butterfly and the Corn Borer
201
11
Pollen Has Always Flown
223
12
The Organic Rule
245
13
Sustaining Agriculture
263
14
Sharing the Fruits
279
15
Food for Thought
295
Acknowledgments
317
Notes
319
Bibliography
337
Index
351
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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
ILLUSTRATIONS
How to regenerate a plant
14
How to tell wild wheat from domesticated wheat
27
Corn and its ancestor, teosinte
33
DNA, the double helix
35
The art of grafting
52
The many faces of Brassica oleracea
70
Mendel’s experiment with peas, showing the assortment of round (R), wrinkly (r), yellow (Y), and green (y) traits
75
The interior of a plant cell
87
From DNA to protein
89
The effect of a transposon, or jumping gene, on the colors of a corn kernel
100
How to clone a gene in a plasmid
118
The polymerase chain reaction, or PCR
121
Two ways to give a plant a new gene: the Agrobacterium method and biolistics
126
How DNA is degraded during digestion
156
How IgE causes an allergic reaction
185
How a refuge delays the onset of resistance to Bt
216
The reactions of nitrogen in the soil
258
How a plant virus spreads, and how plants resist their attack
282
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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
PREFACE
… making the yellow soil express its summer thought in bean leaves and blossoms rather than in wormwood and piper and millet grass, making the earth say beans instead of grass—this was my daily work.
—Henry David Thoreau (1854)
Our civilization rests on food: on our ability to make the earth say beans, to store those beans and fruits and seeds, and to share them. Other creatures might feed their young, but as adults each one fends for itself, spending much of the day doing it. By contrast we humans have learned to farm. Over the last few centuries, advances in science have allowed fewer and fewer farmers to feed more and more people, freeing the rest of us to make and sell each other houses, hats, and video games, to be scientists and writers and politicians, painters, teachers, doctors, spiritual leaders, and talk-show hosts. In some parts of the world, only one person in 200 grows plants or raises animals for food. The other 199 of us buy what we eat.
Whether we tote home sacks from a supermarket or dine out in a restaurant, most of us never give a thought to the growing, processing, packaging, and shipping of our food. Nor are we overly concerned about its safety. We rarely get sick from eating what we buy. We are surprisingly unaware of what it takes to create our bread and breakfast cereal, pasta and rice, those perfect fruits and vegetables, unblemished by insect bites or fungal spots. We do not know what makes our agriculture so efficient and our food so cheap. We cannot tell why it is
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Mendel in the Kitchen: A Scientist’s View of Genetically Modified Foods
nutritious or safe to eat. Free to live our lives with little thought for our food, we ignore the source of the gift, the source of our civilization.
Our civilization rests, in fact, on a history of tinkering with nature, on making the earth say beans, as Thoreau so eloquently said, instead of grass.
Thoreau’s beans were not wild. The pod of a wild bean bursts when its seeds are ripe, flinging the beans far from the parent plant to find a new place to sprout. The bean pods we grow for food do not burst so they can no longer seed themselves. Neither can the wild grasses we have changed over the millennia into our staple food sources: rice, wheat, and corn.
To change a wild plant into a food plant requires changes in the plant’s genes. To boost its yield, to make the earth say more beans, means changing the plant’s genes as well. For thousands of years people have been picking and choosing plants, propagating plants with genetic changes—mutations—that made them better food plants. Thoreau, of course, would not have thought of either beans or grass in terms of genes. He published his influential book, Walden, in which he describes his efforts to make the earth say beans, in 1854. Gregor Mendel’s experiments with peas, which would give rise to the new science of genetics, had not yet been done. Mendel didn’t publish his work until 1866, and its significance wasn’t grasped until more than 30 years after that. Not until the twentieth century did farmers begin to understand that their successes and failures had to do with genes. Yet well before Mendel explained how it worked, farmers were changing plants’ genes.
At the end of the Stone Age, when most people still lived in small tribes hunting wild game and gathering wild plants, the world’s human population was stable at eight to ten million. Then, when farming took hold as a way of life, the population began to grow. By the time of Christ, it had risen to between 100 and 300 million. When Columbus landed in the New World and the spread of food plants around the globe increased, the world’s population was about 450 million. By the late 1700s, when the new science of chemistry entered agriculture, it had doubled to 900 million. A century later, when Mendel’s experi-
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ments were rediscovered, the population of the world was more than one and a half billion.
In just the last hundred years—an instant in human history—the population doubled and redoubled. The number of people on Earth reached three billion in 1950, then jumped to six billion in little more than a single human generation. Yet farmers kept pace through advances in plant breeding: plants’ genes were modified in ways that capitalized on the nitrogen chemists had learned to pull out of the air.
From the 1960s to the 1990s the new crop varieties and expanding fertilizer use—the Green Revolution—continued to meet the world’s food needs. In 1950 1.7 billion acres of farmland produced 692 million tons of grain. In 1992, with no real increase in the number of acres under cultivation, the world’s farmers produced 1.9 billion tons of grain—a 170 percent increase. If India alone had rejected the high-yielding varieties of the Green Revolution, another 100 million acres of farmland—an area the size of California—would have had to be plowed to produce the same amount of grain. That unfarmed land now protects the last of the tigers.
Yet as the twentieth century came to a close, plant breeders began running out of breeding room. The Green Revolution had largely run its course. The increases in the yields of corn, wheat, and rice began shrinking year by year. Earth’s human population, on the other hand, was still growing fast. Eight to nine billion people are expected to populate the planet by 2050. Feeding them is a problem both daunting and complex. Crop yields must be increased simply to provide all people with the same amount of food available to us today—unless more land is brought into production, unless more wilderness is plowed.
As has happened before when famines were predicted, plant scientists searched for new ways to increase the earth’s yield. This time their innovations aren’t called plant breeding but “genetic engineering.” The new crops are not known simply as crops—as were the ones created using earlier ways of modifying plant genes—but genetically engineered, genetically modified, genetically manipulated, transgenic, or genetically altered. Most often they are lumped under the acronyms
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GM, for genetically modified, or GMO, for genetically modified organism.
GMOs have met with strong resistance. Before GMOs, people might have protested the use of synthetic fertilizers or pesticides in modern farming, but they were unconcerned about whatever it was that plant breeders had done to create high-yielding hybrid corn or brilliant red grapefruit or seedless watermelons or canola oil. Now, however, many people seem to agree with Britain’s Prince Charles when he calls the new techniques of plant breeding “dangerous” and against God’s plan. Why?
One reason for this resistance lies in the words themselves. Much human effort goes into changing our environment by building highways, houses, air conditioners, shopping malls, dams, or airplanes. Although individual projects might meet with resistance, few people protest this kind of engineering. Yet the notion that plants are being engineered caught people by surprise. It was rather disquieting. Plants are, after all, natural, aren’t they? Might we not be messing with Mother Nature if we began to engineer plants?
Another reason is that most of us simply don’t know what to make of the molecular techniques that allow scientists to change plant genes or add new ones. We don’t really know, but we suspect it might be dangerous to transfer a gene from one species, such as a bacterium or a fish, to another, such as corn or tomato. Could it be morally wrong to violate the species barrier? What is a species barrier anyway?
What genetic engineering actually is and how it differs from earlier techniques of plant breeding is not understood by many outside the laboratory and breeding plot. Nor do most people understand the effects on the science of plant breeding of new interpretations of patent law and federal regulations concerning food safety and environmental protection. People have heard that scientists themselves oppose genetically modified foods—and a few do, although they are rarely those who know this new science well. Most people lack the time—and often the knowledge—to critically examine the scientific research cited in support of the opposing views of the technology. By writing this book we seek to answer the questions that most people—whether for or against the idea of genetically modified foods—often forget to ask.
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We cannot turn the clock back. The human population is too large, and the earth too small, to sustain us in the ways our ancestors lived. Most of the land that is good for farming is already being farmed. Yet 80 million more humans are being added to the population each year. The challenge of the coming decades is to limit the destructive effects of agriculture even as we continue to coax ever more food from the earth. It is a task made less daunting by new knowledge and new methods—if we use them wisely.
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