The Human Age (34 page)
Today, the monkey gland craze is as passé as Rudolph Valentino, but so many of us have pieces of other nonhuman creatures inside us, it’s surprising that we don’t inadvertently oink, clop, or bleat in embarrassing moments. We think nothing of strolling around with cow and horse valves in our hearts. Raising genetically modified pigs that are more compatible with human tissue, we harvest the blood-thinner heparin from their intestines, and insulin from their pancreases. The fibrous tissue in the spaces
between
the cells in a pig’s bladder, once viewed as mere cushions, are so rich with growth factors that they’re used to “fertilize” war-ravaged human muscles and help them regrow.
When Corporal Isaias Hernandez, a nineteen-year-old marine deployed in Iraq, had 70 percent of his thigh muscle torn off by a
roadside bomb, doctors assumed they’d be amputating the leg. The remains of his thigh looked to him like a half-eaten meal at a Kentucky Fried Chicken restaurant: “You know, like when you take a bite of the drumstick down to the bone?” Quickly scarring over, his thigh sparked constant pain, and doctors prescribed amputation followed by a prosthetic as his only hope.
Then he became a chimera. Volunteering to be part of a clinical research trial, in 2004, he allowed surgeons to insert a paper-thin slice of pig’s bladder, known as extracellular matrix, into the ragged thigh muscle. It began to regenerate. Today, without pain, he—like others—uses a regrown thigh to walk, sit, kneel, bike, climb, and enjoy a normal life. He’ll always be part pig, the part his surgeons refer to affectionately as “pixie dust.”
Is there much difference between ingesting and implanting? We swallow snake and spider venom, and gila monster spit to calm an unruly heart, and cone shell venom for pain. For birth control, millions of women ingest mare’s urine. Our foremost antibiotics come from a cavalcade of fungi. Then there are the coatings, capsules, and liquid additives that go into medicines, concocted from the skin, cartilage, connective tissues, and bones of animals. If we’re comfortable with implanting horse valves in our faulty hearts and pig tissue in our thighs, if we get past the basic idea of raising animals to butcher for their organs and amending our bodies with pieces from lower orders, what else might we think of? Borrowing a spare stomach from a cow so that we can digest food more quickly and lose weight?
Maybe embedding parts from other animals doesn’t seem to bother us because, on the atomic level, we’re living beings composed of nonliving parts. Hence the graveside reminder, “from dust to dust.” Maybe we see it as the ultimate domestication of animals and taming of the soil, which we began long ago in our collective memory, little by little widening their uses. Gradually we’ve gone from animals sleeping under our roof to animals sleeping under our ribs without feeling alarmed.
Oh, that again, the cow is in my bone house
.
Maybe in our desperate hours we gladly extend the idea of kinship from, say, my brother’s kidney to a sheep’s kidney.
Man-made chimeric creatures are a staple in laboratories—mice and other animals bred or grafted with human immune systems, kidneys, skin, muscle tissue—as a common way to study human diseases. Scientists have created sheep with organs that are 40 percent human, monkeys with part-human brains, and mice in which a quarter of the brain cells were human (fortunately they still behaved like mice, but who knows what strange mists galloped across their thoughts). Yet people balked when Japanese scientists announced that, given a year, they could grow a perfect human heart or kidney by tucking a human stem cell into a pig’s embryo, then lodging the embryo in a healthy pig’s womb. Pig valves in humans, no problem. But a pig with human organs?
It’s a sign of our times that the problem with “chimeric embryos” isn’t technological but ethical. It’s doable, but it’s not permissible. Nations would have to agree on what a human being
should be
, and that’s not so obvious anymore. For the first time, we’re asking ourselves: how far are we willing to engineer the world and ourselves? We still feel human when partially enhanced by prostheses, somewhat chimeric, or controlling wearable technology by eyelash-flicks or thoughts. The question has become one of degree. How replaceable are we, yet still legally and attractively human? And where is the line of disgust between enhanced human and monstrous?
Canada has passed the Assisted Human Reproduction Act, which bans the creation of chimeras. The bioethicist Françoise Baylis of Dalhousie University in Halifax, Nova Scotia, helped draft Canada’s guidelines on chimeras.
“We don’t treat all humans well, and we certainly don’t treat animals well,” she insists. “So how do we treat these new beings?”
In the United States, the National Academy of Science permits chimeras but warns against allowing chimeras to breed, because breeding two part-human chimeras could potentially lead to the grotesque (though almost certainly fatal) possibility of a human embryo
growing inside another animal. Remember Rome’s fabled origin, when Romulus and Remus were raised by wolves? Suppose a wolf actually gave birth to a human? Or a sheep did? Almost ten years ago, Esmail Zanjani of the University of Nevada, Reno, announced that he had injected human stem cells into sheep embryos halfway through gestation, and the lambs emerged with human cells throughout their tissues. And not just a few cells. Some of the organs were nearly
half
human. Only the organs. No two-legged sheep with opposable thumbs emerged. Staring at them in photographs, I found they looked eerily human, with long faces, jelly roll falling over the forehead, and down-turned eyes. Would dogs detect an odor both human and sheep?
What scientists still don’t know is if transplanted human stem cells would change an animal’s inherent behaviors, attributes, or personality. As bioethicists rightly argue, the last thing we need is the horror of humanized monkeys or other animals. With less than one-thousandth the brain volume of humans, there’s little danger of mice developing our cognitive abilities. But in an animal closer to us on the evolutionary tree, say, a chimpanzee or bonobo, the merger might just work, especially if the DNA were mixed in the earliest stages of development. What would the orangutan Budi make of monkeys with part-human brains, I wonder?
A laboratory chimera poses a moral paradox. The more human its cells, the better it will serve for testing human cures. Too human, and it’s trapped between worlds, a claustrophobic prisoner. Writing in 1876, when the Industrial Revolution had really begun to pick up steam, one British novelist warned of just such a possibility.
In H. G. Wells’s classic novel
The Island of Dr. Moreau
, a shipwrecked man, rescued by a passing boat, relates a gruesomely fascinating tale of escaping from a nameless Indonesian island populated by sentient monsters whom Dr. Moreau has created through transfusions, transplants, grafts, and other bizarre techniques to create human-animal chimeras. They’re hyena-swine, hog-men, leopard-men, ape-men, little sloth people, and other “Beast Folk,” some of whom have
founded their own colony in the jungle, worship Moreau, and have evolved moral bylaws. The novel shocked Victorian England, which was reeling from a slew of new technologies and from Darwin’s idea that humans descended from apes. The vogue for vivisection provoked controversy, as did eugenics, and the ethical limits of scientific experiments. Wells’s novel brought all of those into question, and also explored British colonialism, the essence of identity, the depravity of torture, and maybe most of all the peril one faces by interfering with nature. In later years, Wells described the wildly successful novel as “an exercise in youthful blasphemy.”
Gene splicing and bioengineering would not appear for a hundred years, but Wells foresaw some of the ethical dilemmas they might pose a little later in the Anthropocene. Suppose, by accident or design, a subhuman chimera emerged, something more intelligent than other animals, but less so than humans? What purpose would it be expected to serve? What sort of home would it find in our society? Would it be relegated to a lower caste? Under what circumstances should we consider a man-made chimera human? What inalienable rights would it possess?
S
winging gamely among the fire-hose vines at the Toronto Zoo, Budi isn’t a cyborg or man-made chimera, and no human has reknit his DNA. He’s just a frisky orangutan kid, an emissary from the wild. But we’re starting to regard his physical nature (and our own) in radically new ways that connect and redefine us. Only the knowledge and what we can do with it are new. The rest is ancient as the family tree we share.
A YOUNG WOMAN
with chestnut hair is seated in front of me in the cinema, slouched down, watching Stanley Kubrick’s
2001: A Space Odyssey
. On the art-house screen, a vegetarian ape idly fingers the scattered bones of a fallen antelope. Slowly an idea begins to take shape. Picking up a bone, he raises it over his head and smashes it down on the rest of the skeleton, over and over, striking and shattering in an orgy of violence, while the vision of a tasty tapir flickers through his head and the pounding chords of Richard Strauss’s
Thus Spake Zarathustra
drive home the message: Man the Hunter is born.
A day later, the ape man uses his weapon to kill the leader of a rival band of apes, while the Strauss soundtrack grows orgasmic with a new drama: the blow-by-blow chords of war. From there, Kubrick treats us to human evolution, artificial intelligence, alien life, and technological pageantry. Cascading into the spacefaring future, we find an astronaut vying with a sentient, mentally disturbed computer (which he subdues with a tool far subtler than an antelope bone). Reaching the apogee of his fate, he’s transfigured in a process that’s too advanced for us relative cavemen (in the cave of the movie theater, anyway) to distinguish from magic. As the credits roll like blankets of stars, rising houselights return us to Earth and a human saga and future that seem all the more epic.
When the chestnut-haired woman gets up to leave, one strand of hair remains on the back of her seat. From that tiny sample, someone could peruse the DNA and know if it belonged to a human female or an Irish setter or a fox, and find clues to her identity: ethnic background, eye color, likelihood of developing various diseases, even her probable life span. One would assume that she has little in common with a mouse or a roundworm, and yet they have a similar number of genes. She’s intimately related to almost every creature that walks, crawls, slithers, or flies, even the ones she’d find icky. Especially those. She shares all but a drop of her genetic heritage with spineless organisms. But that drop really counts.
Thanks to the Human Genome Project’s library of our roughly twenty-five thousand protein-coding genes, available via the Internet to anyone with a yen to peruse it, a micro-stalker could analyze the rungs of our redhead’s DNA, creeping up its spiral ladders, and discovering all sorts of juicy nuggets. Some of the micro-portrait he finds will be quite recent, because by hogging and restyling the environment we’ve altered plants, animals, single-celled organisms, and ourselves. Her DNA will show a panoply of revisions, indicative of our age, which we’ve either stage-managed or accidentally caused. Could the pollutants we use, and the wars we wage, really change our DNA and rewire the human species?
She knows they can, because in her college curriculum, Anthropocene Studies, she’s read research linking exposure to jet fuel, dioxin, the pesticides DEET and permethrin, plastics, and hydrocarbon mixtures to cancer, and not just in the person who had contact with it but for several generations. She’s learned how the arsenic-polluted drinking water in the Ganges delta in Bangladesh can lead to skin cancer, as can workplace exposure to cadmium, mercury, lead, and other heavy metals. Although she was tempted to spend her junior year abroad in Beijing, she’s having second thoughts now that a peer-reviewed
PLOS ONE
study ties life in smog-ridden cities to thickening of the arteries and heightened risk of heart disease. What clinches it is this headline in
Mail Online
: “China starts televising the sunrise on giant TV screens because Beijing is so clouded in smog.” Below it, a video shows a scarlet sunrise on an LED billboard in Tiananmen Square, completely encased by thick gray air, as if the sun were on display in a museum. Several black silhouettes are walking past it on their way to work, some wearing masks. As a daily jogger, she’d be inhaling a lot more pollution than most people, and she figures her genes have already been restyled just by growing up among the master trailblazers of the Human Age.
But she is tempted to read the book of her genes, and discover more about her lineage and genetic biases. For a truly personal profile, all our redhead would need is a vial of her blood and between $100 and $1,000. Such companies as Navigenics or 23andMe will gladly provide a glimpse of her future, a tale still being written but legible enough for genetic fortune-telling. She may have a slightly higher than normal risk of macular degeneration, a tendency to go bald, a gene variant that’s a well-known cause of blood cancer, maybe a different variant associated with Alzheimer’s, the family bane. If she read the report herself, she might not handle that information well. It could kindle needless worry about ailments that will never materialize, or it might warn of an impending but treatable illness, or predict a serious, disabling disease like Huntington’s. As a supposed calmative, such tests are usually marketed as a “recreational”
exercise, to discover if you’re part Cherokee or African or Celt, or Neanderthal, or even related to Genghis Khan, as I may well be.
My mother always said I must be part Mongolian, because of my lotus-pale complexion and squid-ink-black hair.
Something you’re not telling me?
I was tempted to ask. But I knew she’d visited Mongolia with my father long after I was born. What I didn’t know is that one out of every two hundred males on Earth is related to Genghis Khan.
An international team of geneticists conducting a ten-year study of men living in what once was the Mongolian empire discovered that a surprisingly large number share the identical Y chromosome, which is passed down only from father to son. One individual’s Y chromosome can be found in sixteen million men “in a vast section of Asia from Manchuria near the sea of Japan to Uzbekistan and Afghanistan in Central Asia.”