Microcosm

by Carl Zimmer

  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.

  In fact, Kass argues, this disgust is a valuable guide to what we should embrace and reject. There’s something horrifying about an army of human clones or human-animal chimeras. In an age when technology can provide us with so much, Kass has written, “repugnance may be the only voice left that speaks up to defend the central core of our humanity. Shallow are the souls that have forgotten how to shudder.”

  Theologians and philosophers are not the only people making these sorts of arguments. In January 2006, President Bush called for a ban on “animal-human hybrids,” adding that “human life is a gift from our creator, and that gift should never be discarded, devalued or put up for sale.” A bill to ban chimeras, introduced by Senator Sam Brownback of Kansas, states that “respect for human dignity and the integrity of the human species may be threatened by chimeras.”

  To tamper with the essence of human nature—by introducing human brain cells into a mouse, for example, or by altering the genes in a fertilized egg—would be to degrade what it means to be human. In the words of Robert George, a Princeton political scientist and a member of Bush’s Council on Bioethics, “A thing either is or is not a whole human being.”

  To make sense of these arguments, it helps to look back once again at E. coli. Thirty years ago, engineering E. coli was considered an affront to nature, even to God. It defied billions of years of evolution by sporting a gene from a human. Now no one seems to care about it. E. coli sits neglected in its fermenting tanks and laboratory flasks, loaded with imported genes from hundreds of other species, including our own. E. coli starves and suffers as it churns out alien proteins. And yet it no longer offends the wisdom of our repugnance. There are no campaigns to respect the integrity of E. coli as a species, to fight the degradation of human nature that comes from putting human genes into bacteria. It’s hard to imagine someone turning down a prescription for blood thinner because it is the product of the unholy union of human and microbe.

  How can our fear of crossing species boundaries be so strong and yet so mutable? It does not arise from an objective perception of some deep, incontrovertible fact of life. It is a habit of mind. We are all intuitive biologists from childhood. Babies quickly come to expect differences between living things and nonliving ones. Rocks tumble under the force of gravity, for example, but an ant crawls by its own agency. As children grow, they come to recognize different kinds of living things—animals and plants, for example, or cats and dogs. Each kind has its own essence, an invisible force that produces its actions. This intuitive biology comes easily to children, without elaborate training. And it becomes the habitual way in which adults think about life.

  Intuitive biology may have evolved as an adaptation of the human mind, like language and color vision. It may have helped our ancestors organize their understanding of the natural world. The more knowledge our ancestors could gain about animals and plants, the more likely they were to find food and survive. They could predict where to find wildebeests at a certain time of the year, when to look for tubers in the ground, which kinds of fruit were poisonous and which were sweet. Our ancestors became keen connoisseurs of subtle differences between species, such as colors and coat patterns. Those differences could mean the difference between life and death, between eating a poisonous berry and escaping starvation.

  The notion of the integrity of species emerges from our intuitive biology. Even to dream of breaking the species barrier can stir up strong emotions. It’s striking that some of the earliest artwork made by our species includes chimeras. Some 30,000 years ago, for example, a sculptor in Germany carved a piece of ivory into the form of a lion-headed woman. The image, perhaps seen in a dream or a trance, must have had a profound mystical meaning to the sculptor and to all who looked at it. It blurred the essences of species. By violating the rules of intuitive biology, it became magical. Magical hybrids—including the original Chimera, a monster from Greek mythology, part goat, part lion, part snake—turn up again and again throughout history.

  Now modern biology has challenged our intuitive biology. Species are no longer immutable essences but the products of evolution. Darwin argued that humans descended from apes, which descended from older mammals, all the way back to blind, jawless fish. For breaking the rules of intuitive biology, Darwin was punished by being turned into a chimera. Cartoonists drew him with the bearded head of a man and the hairy body of a monkey.

  In 1896, H. G. Wells played on this anxiety with his novel The Island of Dr. Moreau. Dr. Moreau, his sense of morality lost in the lust for scientific knowledge, surgically combines different animals into humanlike monsters.

  “The thing is an abomination,” the narrator declares to Moreau. The evil doctor replies, “To this day I have never troubled about the ethics of the matter…. The study of Nature makes a man at last as remorseless as Nature.”

  Wells punishes Moreau for his transgression with an uprising of the monsters. The Island of Dr. Moreau is a prophetic book, especially given that Wells wrote it before biologists had discovered genes. Once scientists understood DNA, it became the new essence of life. Today our true selves lie in our genes. The origin of our genome at conception becomes the origin of a new life. DNA has also come to define the essence of a species, what distinguishes
it from other living kinds. Thus came a horror at the thought of mingling genes from different species, particularly species that look as different from each other as humans and E. coli. Genetic engineering defies a powerful rule we use to organize the living world. Setting the boundaries of species is not the business of humans. When humans tamper with those boundaries, they create monsters, they unleash horrors.

  Our intuitive biology did not evolve because it was true. It evolved because it was useful. It allowed our ancestors to make good decisions based on the information they could gather, and those decisions raised their odds of surviving and reproducing. But intuitive biology is not a reliable guide to the deep truths of life. What is the essence of E. coli as a species, for example? It’s not being a harmless, sugar-feeding, flagella-producing microbe. Within the species we call E. coli, you can also find aggressive defenders of the gut that shut out disease-causing pathogens. You can find many pathogens equipped with weapons not found in harmless strains. Some strains straddle the divide—they are beneficial, but they also carry many of the genes that make other strains killers. And many of these strains evolved by being infected with viruses that show no respect for our beloved species boundaries. There is no immutable essence that unites E. coli.