Frankenstein's Cat: Cuddling Up to Biotech's Brave New Beasts (6 page)

For an extreme example, consider doctors’ long-standing hope of using animals as organ donors for human patients. Worldwide, there’s an acute shortage of human donors—in the United States alone, ten people awaiting new organs die every day—and animal organs could help fill the gap. Throughout the twentieth century, surgeons experimented with this kind of “xenotransplantation,” putting monkey parts into humans suffering from various diseases and defects.
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The most famous case came in 1984, when an infant with an underdeveloped heart received a replacement heart from a baboon. It was a daring experiment, but Baby Fae, as the patient became known, survived only twenty days with the new organ. Other recipients of monkey organs haven’t fared much better. In the 1990s, for example, two patients received livers from baboons; one lived for seventy days after the operation, the other for just twenty-six. And none of the six patients who were given baboon kidneys survived longer than two months. The problem with these kinds of cross-species transplants is rejection; our immune systems expertly, and correctly, identify implanted animal parts as foreign tissues and attack the new organs.

Genetic engineering, however, may give us a way to create animal organs suitable for transplant into our own bodies. Using cognitively sophisticated monkeys and apes as organ donors has become taboo, so researchers are now focusing on pigs, which are widely farmed and have organs that are about the same size as our own. In fact, replacing defective human heart valves with pig valves has become a routine medical procedure. (This interspecies transfer of
tissue
, rather than a whole organ, is known as xenografting.) The surfaces of pig cells are adorned with signature sugars, which immediately tip our human immune systems off to the fact that something strange has entered the body. Surgeons can keep pig valves from provoking an immune response by treating them with a special preservative before they’re implanted in the human body. It works fine for this small piece of tissue, but it’s not feasible for entire organs, which must be fresh and viable when they’re transplanted. Enter genetic engineering: scientists have now created pigs in which the gene that codes for these distinct sugars is “knocked out,” hoping that organs from these pigs will pass more easily as native human tissue.

Using these knockout pigs as organ donors could save thousands of human lives, but it also means that we’d be turning sentient creatures into more suitable sacrificial lambs, engineering animals purely so we can later dismantle them. That’s instrumental in the extreme. Yes, we already break pigs into pieces to make our morning bacon, but genetic modification could expand the market for pig parts.

By and large, we accept the use of animals as objects and tools. Sixty-two percent of Americans surveyed in a Gallup poll, for example, deemed it “morally acceptable” to use animals for medical research, and despite the growth of the animal rights movement, there aren’t many vegetarians.
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And what does a T-bone steak represent if not a reduction of an animal to parts, to its instrumental value? There are issues with farming, of course, especially the industrial-scale factory farming that is the norm today. But whatever our objections to the system itself
,
the truth is that most of us accept the idea that we can use an animal’s body to nourish our own.

For most of us, then, the real ethical question surrounding pharm animals comes down to the genetic engineering itself. Is there something about editing DNA and remixing biological material that is just inherently wrong? Monstrous mash-ups have long menaced the imagination, and critics of biotechnology worry that breaching species barriers violates the rules of God or nature or both. These concerns are magnified when researchers combine animal DNA with our own, by, say, putting a human gene into a goat.

As it happens, some scientists are doing a whole lot more than inserting a single human gene into another species—they’re creating human-animal “chimeras,” whose bodies contain both human and animal cells. The difference between a transgenic animal, which has a single gene from a foreign species present in every cell, and a chimeric animal, which has cells that come from two different species, can be visualized this way: Imagine a transgenic animal as one in which every cell is blue with a single red dot, while a chimeric one looks more like a patchwork quilt, with some cells that are entirely blue and others that are entirely red. (To continue the analogy, a hybrid—created when the sperm of one species fertilizes the egg of another—would be a creature in which all cells are purple.)
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For example, in a series of recent experiments, researchers at the University of Nevada, Reno, injected human stem cells—shape-shifting cells capable of becoming a variety of tissues—into sheep fetuses. As the lambs developed in utero, they incorporated these cells into their bodies, resulting in sheep that had hearts, livers, and pancreases that were part sheep and part human.

These interspecies combinations can raise uncomfortable existential questions, threatening our sense of uniqueness. If we can make our cells spring to life in a sheep or make a piece of our biological code work in a beady-eyed little rodent, what is it, exactly, that separates man from beast? Several states, including Louisiana and Arizona, have passed laws forbidding the creation of “human-animal hybrids,” and U.S. Senator Sam Brownback has pushed for similar legislation on a national level. Brownback’s proposed Human-Animal Hybrid Prohibition Act noted that “human dignity and the integrity of the human species are compromised by human-animal hybrids.” (It’s interesting to note that we rarely hear the flip side of this argument—that human-animal hybrids threaten the dignity of
animals
.)

From an ethical standpoint, human-animal mixtures are especially tricky when they involve the melding of minds. Animal cognition has much in common with our own, but certain kinds of autobiographical memory, language, number sense, and aspects of social cognition are unique to humans. At least, they are for the time being; scientists have already started manipulating genes involved in some of these capabilities. In 2009, German researchers engineered mice that carried a human version of FOXP2, a gene thought to be partially responsible for our unique way with words. (Mutations in the gene can cause speech and language disorders.) Giving mice the human FOXP2 variant changed the sound of the rodents’ squeaks and the shape and size of their neurons.

What if, instead of making sheep with human cells in their livers, the scientists at the University of Nevada had made sheep, rats, or monkeys with a mass of human cells in their brains? Would these animals suddenly have a sense of justice? An ability to count? Would they be self-aware enough to realize that they were spending their lives as experimental subjects? If so, should we spring them from their cages? How many human brain cells and human behaviors would a sheep, rat, or ape need to display in order to qualify for enhanced legal status, legislative representation, and other rights? Neither fully animal nor fully human, these creatures would occupy an ethical no-man’s-land.

These sticky philosophical questions, among other concerns, led the Britain’s Academy of Medical Sciences to conclude in its 2011 report that research that might make an animal’s brain more “humanlike” should be subject to special scrutiny. Similarly, in the United States, the National Academy of Sciences has issued guidelines stipulating that any experiment that might cause human cells to end up in animal brains must have a strong scientific rationale to be approved.

Clearly, not all human-animal mixtures create the same quandaries. Putting a gene for human lysozyme in a goat does not make that animal a person any more than putting a pig valve into a human heart makes that surgical patient a pig.
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Though both of these creatures are a mix of human and nonhuman animal, neither occupies some new, undefinable moral category. No one would seriously argue that a goat with a single human gene should get the right to vote or that a human with a pig part inside should be kept in a sty.
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Even as we worry about breaching species barriers, biologists argue over just what it is that makes a “species” in the first place. Though “species” exist as rigid categories in our minds—and are a convenient way for us to label the natural world—they’re considerably more fluid in nature. After all, Darwin’s theory of evolution is based on the idea that there are smooth transitions, rather than sharp dividing lines, between humans and chimpanzees, between rats and rabbits. The genetic characteristics of a species are not set in stone; whatever it is that makes a human a human and a chimp a chimp is constantly evolving.

What’s more, genes from different species sometimes mingle in the natural world. Animals occasionally pursue torrid interspecies affairs, giving us ligers and tigons and zorses. (Oh my!) Different species of bacteria can spontaneously swap DNA in the wild or transfer novel genes into insects, worms, and other animals. The parasite that causes Chagas’ disease, a chronic illness associated with heart and digestive problems, can slip its DNA into our own genomes, and pea aphids have borrowed genes from a fungus that turns the bugs’ bodies red. We can change animals faster and in more profound ways than nature does on its own, but the point is that there’s nothing inherently sacred about a species’s genome—it’s an amorphous, ever-changing thing.

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There is logic and then there’s emotion. We don’t have to believe that the genome is sacred or that humans are divine to feel a sense of revulsion when we imagine a mouse with a human brain. This reaction is what ethicists call the “yuck factor,” and it’s what makes us recoil when we consider the prospect of drinking wastewater (even after it’s been decontaminated) or adopting a dog that glows neon red.

The bioethicist Leon Kass believes that we should pay careful attention to those visceral, gut responses to biotechnology. His essay “The Wisdom of Repugnance” was initially intended as a missive against human cloning, but his arguments have since been applied to all sorts of biotechnologies, including genetic engineering. “In critical cases,” Kass wrote, “repugnance is the emotional expression of deep wisdom, beyond reason’s power fully to articulate it … Repugnance, here as elsewhere, revolts against the excesses of human willfulness, warning us not to transgress what is unspeakably profound.” Kass also argues that “repugnance may be the only voice left that speaks up to defend the central core of our humanity.”

A knot in the throat or a pit in the stomach may suggest that we’re approaching dangerous territory and need to consider our actions carefully, but we needn’t let disgust run the show. After all, as an emotion, disgust is not always grounded in the world of reason. For example, the Academy of Medical Sciences discovered that while we’re uneasy about giving animals human faces, limbs, hair, and skin, we’re far less perturbed by making animals look human on the inside. This discrepancy, the report concluded, “appears to be irrational … [O]ne can compare this distaste at the humanised appearance of an animal with the common reaction of unease at the sight of human disfigurement. This is a primitive reaction which has no inherent ‘wisdom.’”

Repugnance may be a good spark for public dialogue, but it shouldn’t be a substitute for it. Acting in an ethical manner sometimes requires rising above raw emotion. What if we had let the visceral disgust some people once felt at seeing an interracial couple be the final word on interracial marriage? A gut instinct shouldn’t be a death sentence, an emotional reaction a replacement for moral and ethical reasoning.

So if we discount the “yuck factor,” how are we to evaluate the genetic alteration of animals? Bernard Rollin, a philosopher at Colorado State University, proposes that we use a simple ethic: “conservation of welfare.” Simply put, he says, the principle holds: “If you’re going to modify a line of animals, the resultant animals should be no worse off from a welfare point of view—and preferably better.”

Some genetically engineered animals would certainly fail this test. The most infamous case is the “Beltsville pig,” which carried the gene for human growth hormone. The goal was to create a pig that gained weight faster, required less food, and had less body fat than normal swine. The resulting transgenic pigs were indeed leaner and needed fewer calories to bulk up, but from a welfare point of view, the modification was catastrophic. The list of these little piggies’ afflictions reads like a medical encyclopedia: joint disease, kidney disease, heart disease, diabetes, weakened immune systems, diarrhea, arthritis, ulcers, pneumonia, sexual dysfunction, and more. The swine also had bulging eyes and thickened skin, and they were lethargic and uncoordinated.

But not all genetic tinkering causes such animal welfare disasters. The precise effects of our engineering depend on the particular gene we insert and the snippet of regulatory DNA to which we attach it. In pharming, for instance, scientists have been able to restrict the production of foreign proteins to an animal’s mammary gland by attaching it to a promoter active only in that part of the body. Our ability to limit a gene’s activity to this one organ may explain why, by and large, pharm animals do not suffer from any unusual health problems. For example, the FDA examined seven generations of the ATryn goats, and found no evidence of strange ailments or illnesses. These goats have utterly normal lives—they just spend their days unknowingly secreting human medicine in their milk.

According to the conservation-of-welfare framework, the ATryn goats are ethically acceptable and the Beltsville pig is not. And the Beltsville pig is wrong not because it was genetically engineered but because it
suffered
. This ethical framework considers genetic engineering to be value-neutral—biotechnology is merely a tool, and whether it’s a force for good or evil depends entirely on how we deploy it. As Rollin put it in his book
The Frankenstein Syndrome
, “It is simply false that all genetic engineering must harm animals. Unless one assumes that all species of animals exist currently at their maximal possible state of happiness or well-being of welfare, such a claim is not legitimate.”