The Violinist's Thumb: And Other Lost Tales of Love, War, and Genius, as Written by Our Genetic Code (46 page)

That shouldn’t surprise us. Genetics has fascinated people practically since Mendel tilled his first pea plant. But a parasite of revulsion and confusion feeds on that fascination, and the future of genetics will turn on whether we can resolve that push-pull, gotta-have-it-won’t-stand-for-it ambivalence. We seem especially mesmerized/horrified by genetic engineering (including cloning) and by attempts to explain rich, complicated human behavior in terms of “mere” genes—two often misunderstood ideas.

Although humans have been genetically engineering animals and plants since the advent of agriculture ten thousand years ago, the first explicit genetic engineering began in the 1960s. Scientists basically started dunking fruit fly eggs in DNA goo, hoping that the porous eggs would absorb something. Amazingly these crude experiments worked; the flies’ wings and eyes changed shape and color, and the changes proved heritable. A decade later, by 1974, a molecular biologist had developed tools to splice DNA from different species together, to form hybrids. Although this Pandora restricted himself to microbes, some biologists saw these chimeras and shivered—who knew what was next? They decided that scientists had gotten ahead of themselves, and called for a moratorium on this recombinant
DNA research. Remarkably, the biology community (including the Pandora) agreed, and voluntarily stopped experimenting to debate safety and rules of conduct, almost a unique event in science history. By 1975 biologists decided they did understand enough to proceed after all, but their prudence reassured the public.

That glow didn’t last. Also in 1975, a slightly dyslexic myrmecologist born in evangelical Alabama and working at Harvard published a six-pound, 697-page book called
Sociobiology.
Edward O. Wilson had labored for decades in the dirt over his beloved ants, figuring out how to reduce the byzantine social interactions of serfs, soldiers, and queens into simple behavioral laws, even precise equations. In
Sociobiology
the ambitious Wilson extended his theories to other classes, families, and phyla, ascending the evolutionary ladder rung by rung to fish, birds, small mammals, mammalian carnivores, and primates. Wilson then plowed straight through chimps and gorillas to his notorious twenty-seventh chapter, “Man.” In it, he suggested that scientists could ground most if not all human behavior—art, ethics, religion, our ugliest aggressions—in DNA. This implied that human beings were not infinitely malleable but had a fixed nature. Wilson’s work also implied that some temperamental and social differences (between, say, men and women) might have genetic roots.

Wilson later admitted he’d been politically idiotic not to anticipate the firestorm, maelstrom, hurricane, and plague of locusts that such suggestions would cause among academics. Sure enough, some Harvard colleagues, including the publicly cuddly Stephen Jay Gould, lambasted
Sociobiology
as an attempt to rationalize racism, sexism, poverty, war, a lack of apple pie, and everything else decent people abhor. They also explicitly linked Wilson with vile eugenics campaigns and Nazi pogroms—then acted surprised when other folks lashed out. In 1978,
Wilson was defending his work at a scientific conference when a few half-wit activists stormed onstage. Wilson, in a wheelchair with a broken ankle, couldn’t dodge or fight back, and they wrested away his microphone. After charging him with “genocide,” they poured ice water over his head, and howled, “You’re all wet.”

By the 1990s, thanks to its dissemination by other scientists (often in softer forms), the idea that human behavior has firm genetic roots hardly seemed shocking. Similarly, we take for granted today another sociobiological tenet, that our hunter-scavenger-gatherer legacy left us with DNA that still biases our thinking. But just as the sociobiology ember was flickering, scientists in Scotland spurted kerosene on the public’s fear of genetics by announcing, in February 1997, the birth of probably the most famous nonhuman animal ever. After transferring adult sheep DNA into four hundred sheep eggs, then zapping them
Frankenstein-
style with electricity, the scientists managed to produce twenty viable embryos—clones of the adult donor. These clones spent six days in test tubes, then 145 in utero, during which time nineteen spontaneously aborted. Dolly lived.

In truth, most of the humans gawking at this little lamb cared nothing about Dolly qua Dolly. The Human Genome Project was rumbling along in the background, promising scientists a blueprint of humanity, and Dolly stoked fears that scientists were ramping up to clone one of our own—and with no moratorium in sight. This frankly scared the bejeezus out of most people, although Arthur Caplan did field one excited phone call about the possibility of cloning Jesus himself. (The callers planned to lift DNA from the Shroud of Turin, natch. Caplan remembered thinking, “You are trying to bring back one of the few people that are supposed to come back anyway.”)

Dolly, the first cloned mammal, undergoes a checkup. (Photo courtesy of the Roslin Institute, University of Edinburgh)

Dolly’s pen mates accepted her, and didn’t seem to care about her ontological status as a clone. Nor did her lovers—she eventually gave birth to six (naturally begotten) lambs, all strapping. But for whatever reason, human beings fear clones almost instinctively. Post-Dolly, some people hatched sensational supposes about clone armies goose-stepping through foreign capitals, or ranches where people would raise clones to harvest organs. Less outlandishly, some feared that clones would be burdened by disease or deep molecular flaws. Cloning adult DNA requires turning on dormant genes and pushing cells to divide, divide, divide. That sounds a lot like cancer, and clones do seem prone to tumors. Many scientists also concluded (although Dolly’s midwives dispute this) that Dolly was born a genetic geriatric, with
unnaturally old and decrepit cells. Arthritis did in fact stiffen Dolly’s legs at a precocious age, and she died at age six (half her breed’s life span) after contracting a virus that, à la Peyton Rous, gave her lung cancer. The adult DNA used to clone Dolly had been—like all adult DNA—pockmarked with epigenetic changes and warped by mutations and poorly patched breaks. Such flaws might have corrupted her genome before she was ever born.
^*

But if we’re toying with playing god here, we might as well play devil’s advocate, too. Suppose that scientists overcome all the medical limitations and produce perfectly healthy clones. Many people would still oppose human cloning on principle. Part of their reasoning, however, relies on understandable but thankfully faulty assumptions about genetic determinism, the idea that DNA rigidly dictates our biology and personality. With every new genome that scientists sequence, it becomes clearer that genes deal in probabilities, not certainties. A genetic
influence
is just that, only that. Just as important, epigenetic research shows that the environment changes how genes work and interact, so cloning someone faithfully might require preserving every epigenetic tag from every missed meal and every cigarette. (Good luck.) Most people forget too that it’s already too late to avoid exposure to human clones; they live among us even now, monstrosities called identical twins. A clone and its parent would be no more alike than twins are with all their epigenetic differences, and there’s reason to believe they’d actually be less alike.

Consider: Greek philosophers debated the idea of a ship whose hull and decks were gradually rotting, plank by plank; eventually, over the decades, every original scrap of wood got replaced. Was it still the same ship at the end? Why or why not? Human beings present a similar stumper. Atoms in our body get recycled many, many times before death, so we don’t have the same bodies our whole lives. Nevertheless we feel like the same person. Why? Because unlike a ship, each human has an
uninterrupted store of thoughts and remembrances. If the human soul exists, that mental memory cache is it. But a clone would have different memories than his parent—would grow up with different music and heroes, be exposed to different foods and chemicals, have a brain wired differently by new technologies. The sum of these differences would be dissimilar tastes and inclinations—leading to a dissimilar temperament and a distinct soul. Cloning would therefore not produce a doppelgänger in anything but literal superficialities. Our DNA does circumscribe us; but where we fall within our range of possibilities—our statures, what diseases we’ll catch, how our brains handle stress or temptation or setbacks—depends on more than DNA.

Make no mistake, I’m not arguing in favor of cloning here. If anything, this argues against—since what would be the point? Bereaved parents might yearn to clone Junior and ease that ache every time they walked by his empty room, or psychologists might want to clone Ted Kaczynski or Jim Jones and learn how to defuse sociopaths. But if cloning won’t fulfill those demands—and it almost certainly cannot—why bother?

Cloning not only riles people up over unlikely horrors, it distracts from other controversies about human nature that genetic research can, and has, dredged up. As much as we’d like to close our eyes to these quarrels, they don’t seem likely to vanish.

Sexual orientation has some genetic basis. Bees, birds, beetles, crabs, fish, skinks, snakes, toads, and mammals of all stripes (bison, lions, raccoons, dolphins, bears, monkeys) happily get frisky with their own sex, and their coupling often seems hardwired. Scientists have discovered that disabling even a single gene in mice—the suggestively named
fucM
gene—can turn female mice into lesbians. Human sexuality is more nuanced, but gay men (who have been studied more extensively than gay
women) have substantially more gay relatives than heterosexual men raised in similar circumstances, and genes seem like one strong differentiator.

This presents a Darwinian conundrum. Being gay decreases the likelihood of having children and passing on any “gay genes,” yet homosexuality has persisted in every last corner of the globe throughout all of history, despite often-violent persecution. One theory argues that perhaps gay genes are really “man-loving” genes—androphilic DNA that makes men love men but also makes women who have it lust after men, too, increasing their odds of having children. (Vice versa for gynophilic DNA.) Or perhaps homosexuality arises as a side effect of other genetic interactions. Multiple studies have found higher rates of left-handedness and ambidextrousness among gay men, and gay men frequently have longer ring fingers, too. No one really believes that holding a salad fork in one hand or the other causes homosexuality, but some far-reaching gene might influence both traits, perhaps by fiddling with the brain.

These discoveries are doubled-edged. Finding genetic links would validate being gay as innate and intrinsic, not a deviant “choice.” That said, people already tremble about the possibility of screening for and singling out homosexuals, even potential homosexuals, from a young age. What’s more, these results can be misrepresented. One strong predictor of homosexuality is the number of older biological brothers someone has; each one increases the odds by 20 to 30 percent. The leading explanation is that a mother’s immune system mounts a progressively stronger response to each “foreign” Y chromosome in her uterus, and this immune response somehow induces homosexuality in the fetal brain. Again, this would ground homosexuality in biology—but you can see how a naive, or malicious, observer could twist this immunity link rhetorically and equate homosexuality with a disease to eradicate. It’s a fraught picture.

Race also causes a lot of discomfort among geneticists. For one thing, the existence of races makes little sense. Humans have lower genetic diversity than almost any animal, but our colors and proportions and facial features vary as wildly as the finalists each year at Westminster. One theory of race argues that near extinctions isolated pockets of early humans with slight variations, and as these groups migrated beyond Africa and bred with Neanderthals and Denisovans and who knows what else, those variations became exaggerated. Regardless, some DNA must differ between ethnic groups: an aboriginal Australian husband and wife will never themselves produce a freckled, red-haired Seamus, even if they move to the Emerald Isle and breed till doomsday. Color is encoded in DNA.