Authors: Carl Zimmer
Drugs made through genetic engineering have also turned out to be just as vulnerable to market forces as conventional ones. Drug companies have been trying to increase their sales by expanding our definition of what it means to be sick. Genetically engineered drugs have been promoted this way as well. Genentech originally got approval from the Food and Drug Administration to sell its
E. coli–
produced growth hormone to treat children whose bodies couldn’t make it themselves. But in 1999 the company had to pay $50 million to settle charges that its drug was being marketed to children who were merely shorter than average.
E. coli’
s thirty-year history of genetic engineering is worth considering when we judge the new biotechnology that has come in its wake. We must resist empty fear and empty hype. We must instead be realistic, always remembering how both nature and society actually work.
One of the great dreams of biotechnology has been to end famine, for example. Julian Huxley speculated as far back as 1923 that scientists would create a limitless supply of food (along with purple oceans). The dream lived on in the 1960s with promises of oil-fed yeast. When scientists successfully inserted foreign genes in
E. coli,
advocates for genetic engineering promised more food for a starving world. In the 1970s, the Green Revolution—the result of breeding new varieties of crops and using plenty of fertilizer—had dramatically increased farm productivity. But the world’s population, and thus its hunger, were still growing. Scientists began trying to engineer bacteria to make fertilizer by capturing nitrogen from the air. Most recently, scientists have turned their attention to engineering plants themselves. Transgenic crops are being promoted not as a way to make bigger profits but as a way to fight hunger and malnutrition. Crops that can resist viruses and insects will increase harvests. Crops that can resist herbicides will allow farmers to fight weeds more effectively, increasing the yield even more. Norman Borlaug, who won a Nobel Peace Prize for his work on the Green Revolution, claimed that genetically modified crops would pick up where his own work had left off, feeding the world for another century.
Anyone who questioned this prediction, Borlaug suggested, was dooming the world’s poor to famine. “The affluent nations can afford to adopt elitist positions and pay more for food produced by the so-called natural methods; the 1 billion chronically poor and hungry people of this world cannot,” he wrote in 2000. “New technology will be their salvation, freeing them from obsolete, low-yielding, and more costly production technology.”
One of the promising crops Borlaug—as well as many other advocates—pointed to was Golden Rice, a strain of rice engineered to make vitamin A. Vitamin A deficiency affects roughly 200 million people worldwide. Up to half a million children become blind each year, half of whom will die within a year of losing their sight. In the late 1990s, Swiss scientists began inserting genes from daffodils and bacteria into the rice genome to produce vitamin A. They formed a partnership with the corporation Syngenta to develop the rice and distribute it free to farmers who make less than $10,000 a year. Ingo Potrykus, one of the inventors, appeared on the cover of
Time
in 2000, alongside the headline “THIS RICE COULD SAVE A MILLION KIDS A YEAR,” which was followed in small print by “…but protesters believe such genetically modified foods are bad for us and our planet. Here’s why.”
Potrykus had little patience for those protesters. “In fighting against ‘Golden Rice’ reaching the poor in developing countries,” he declared in 2001, “GMO opposition has to be held responsible for the foreseeable unnecessary death and blindness of millions of poor every year.”
Strong words, particularly given how embryonic the research on Golden Rice was when Potrykus uttered them. He and his colleagues had published their first results only the previous year. They had managed to produce only small amounts of vitamin A in the rice’s tissues, far too little to wipe out vitamin A deficiency. In 2005, four years after Potrykus accused his critics of mass murder, Syngenta scientists discovered that adding an extra gene from corn helped boost the level of the vitamin A precursor more than twentyfold. It was a huge increase, but there’s no solid evidence yet of how much benefit it brings to people who eat it. Some nutritionists have warned that it may not bring much benefit at all, because vitamin A has to be consumed along with dietary fat in order to be properly absorbed by the body. It’s possible to suffer vitamin A deficiency—even to go blind—on a diet that contains vitamin A. Foods such as milk, eggs, and many vegetables offer the right combination of vitamin A and fat, but rice does not. Just because Golden Rice is at the cutting edge of genetic engineering doesn’t mean that it will cut down vitamin A deficiency any more than conventional methods have.
Using words like
salvation
to describe transgenic crops makes as little sense as calling them Frankenfoods. We are thrown back and forth between the extremes of abject terror and hope for miracles of loaves and transgenic fish. Genetically modified crops are hardly miraculous. They are living things, as much subject to the rules of life as
E. coli
or humans. And just as
E. coli
has evolved defenses against some of our best antibiotics, natural selection is undermining the worth of the most popular transgenic crops.
About 80 percent of all the transgenic crops planted in 2006 were engineered for the same purpose: to be resistant to a herbicide known as glyphosate. Glyphosate kills plants by blocking the construction of amino acids that are essential to their survival. It attacks enzymes that only plants use, with the result that it’s harmless to people, insects, and other animals. And unlike other herbicides that wind up in groundwater, glyphosate stays where it’s sprayed, degrading within weeks. A scientist at the Monsanto Company discovered glyphosate in 1970, and the company began selling it as Roundup in 1974. In 1986, scientists engineered glyphosate-resistant plants by inserting genes from bacteria that could produce amino acids even after a plant was sprayed with herbicides. In the 1990s, Monsanto and other companies began to sell glyphosate-resistant corn, cotton, sugar beets, and many other crops. Instead of applying a lot of different herbicides, farmers found they could hit their fields with a modest dose of glyphosate alone, which wiped out weeds without harming their crops. Studies indicated that farmers who grew the transgenic crops used fewer herbicides than those who grew nontransgenic plants—77 percent fewer in Mexico, for example—while getting a significantly higher yield.
For a while it seemed as if glyphosate would avoid the fate of many other herbicides before it: the evolution of weeds resistant to herbicides. Glyphosate seemed to strike at such an essential part of their biology that no defense could possibly evolve. Of course, it also seemed for a while as if
E. coli
couldn’t evolve resistance to Michael Zasloff’s antimicrobial peptides. And after glyphosate-resistant crops had a few years to grow, farmers began to notice horseweed and morning glory and other weeds encroaching once more on their fields. Farmers in Georgia have had to destroy fields of cotton because of infestations of resistant Palmer amaranth. When scientists have studied these resurgent weeds, they’ve discovered genes that now make the plants resistant to glyphosate.
There’s no evidence that these weeds acquired their resistance from the transgenic crops. They most likely got it the old-fashioned way: they evolved it. Using glyphosate on transgenic crops proved to be so cheap and effective that farmers flooded huge swaths of land with a single herbicide. They created an enormous opportunity for weeds that could resist glyphosate and drove the quick evolution of stronger and stronger resistance. And once the weeds evolved their resistance, they appear to have passed on the resistance genes to other weedy species.
When antibiotics fail against
E. coli
and other bacteria, it may take years for a new kind of antibiotic to emerge. The pipeline of transgenic crops is equally sludgy. It wasn’t until 2007, more than twenty years after the invention of glyphosate-resistant crops, that scientists announced they had engineered plants with genes that make them resistant to another herbicide, known as dicamba. Monsanto licensed the technology but said it wouldn’t have dicamba-resistant crops ready for sale for another three to seven years. In the meantime, farmers can resort to old-fashioned methods to slow the evolution of resistance, rotating crops and using a combination of herbicides.
Although there’s a lot of déjà vu in biotechnology today, some scientists have been carefully studying the fate of
E. coli
in the 1970s in order to avoid some of the mistakes their predecessors made. Synthetic biologists have become particularly keen historians, learning how the pioneers in their field grappled with risks, regulations, and the public perception of their work. Rather than make synthetic biology the privileged domain of an elite, Drew Endy and his colleagues are inviting the public to join in the experience. Anyone can download the codes for BioBricks. The
E. coli
camera is now appearing in science museums, and high school students are entering synthetic biology competitions. And rather than put all their efforts into creating a big moneymaker like insulin, synthetic biologists are trying to make cheap drugs for malaria, to demonstrate the good that can come of their work.
Synthetic biologists want to preserve this open-source spirit despite the fact that their tools may someday be used for evil ends. It’s conceivable, for example, that a government might design an organism for biological warfare. Synthetic biologists fear that if the government takes over their research, innovations will dry up. They argue that the best way to defeat an engineered pathogen is to harness the collective creativity of an open community. By keeping synthetic biology free of excessive regulations and patents, its founders hope they can foster an artificial version of the open-source evolution that has served
E. coli
so well for millions of years.
“IT IS CONFUSION”
In the 1970s, genetically engineered
E. coli
frightened people not just with its potential risks. It touched something deeper—a feeling that genetic engineering is something humans were simply not meant to do. Genetic engineering would disrupt the order of nature, the result of billions of years of evolution. Shuttling genes or other biological material from species to species would blur barriers that had been established long before humans existed, threatening to tear down the very tree of life.
“We can now transform that evolutionary tree into a network,” declared Robert Sinsheimer, a biologist at the University of California, Santa Cruz. “We can merge genes of most diverse origin—from plant or insect, from fungus or man as we wish.” Humans, Sinsheimer believed, were not prepared for this responsibility: “We are becoming creators—makers of new forms of life—creations that we cannot undo, that will live on long after us, that will evolve according to their own destiny. What are the responsibilities of creators—for our creations and for all the living world into which we bring our inventions?”
One newspaper called genetic engineering on
E. coli
“the Frankenstein project.” Tampering with DNA, the MIT biologist Jonathan King declared, was “sacrilegious.” Two political activists, Ted Howard and Jeremy Rifkin, condemned genetic engineering in a 1977 book called
Who Should Play God?
Thirty years later, critics of biotechnology continue to play the Prometheus card. In 1999, for example, Rifkin organized a full-page ad representing a number of organizations that were demanding controls on biotechnology. The ad, which appeared in
The New York Times,
displayed two examples of the new horrors humanity faced: a human ear growing from the back of a mouse and the first cloned animal, a sheep named Dolly. Across the top of the ad was the headline “Who Plays God in the Twenty-first Century?”
The genetic structures of living beings are the last of Nature’s creations to be invaded and altered for commerce…. Does anyone think it’s shocking [that the] infant biotechnology industry feels it’s okay to capture the evolutionary process, and to reshape life on earth to suit its balance sheets?…to take over Nature’s work?…Whether you give credit to God, or to Nature, there is a boundary between life forms that gives each its integrity and identity.
“To God, or to Nature”—an intriguing choice. It is certainly true that Christianity and Judaism have an uneasy relationship with biotechnology. After all, in the first pages of Genesis, the Bible makes the essences of species paramount:
And God said, let the earth bring forth grass, the herb yielding seed, and the fruit tree yielding fruit after his kind…. And God created great whales and every living creature that moveth, which the waters brought forth abundantly after their kind, and every winged fowl after his kind…. And God said, let the earth bring forth the living creature after his kind, cattle and creeping thing, and beast of the earth after his kind, and it was so.
In Leviticus, humankind is instructed to keep those distinctions clear: “Thou shalt not let thy cattle gender with a diverse kind: thou shalt not sow thy field with mingled seed.”
The one kind of life most important of all in the Bible is, of course, our own. Made in God’s image, we must never come close to blurring the distinction between us and animals: “Neither shalt thou lie with any beast to defile thyself therewith: neither shall any woman stand before a beast to lie down thereto: it is confusion.”
For many conservatives today, biotechnology’s threat to human nature, rather than to nature, is most alarming. “Using human procreation to fuse animal-human runs counter to the sacredness of human life and man created in the image of God,” writes Nancy L. Jones of the conservative Center for Bioethics and Human Dignity.
Some conservatives don’t cite chapter and verse, but they agree that crossing the species barrier degrades human nature. The most prominent of these critics is Leon Kass. After his encounter with Paul Berg in the early 1970s, Kass continued to write and speak about bioethics, and from 2002 to 2005 he was the chairman of President George W. Bush’s Council on Bioethics. In his arguments against chimeras and cloning, he says that the gut feeling that there’s something disgusting about them is its own evidence that they’re wrong. Kass calls this reliable disgust “the wisdom of repugnance.” We just
know
that certain things are wrong, such as incest and mutilating a corpse. Our inability to give a rational explanation for our feelings does not deny their importance.