The Exciting and Terrifying Future of DNA Editing
Siddhartha Mukherjee's new book delivers a sweeping history of genetics—from the cockamamie ideas that preceded the birth of the field to a striking picture of what the future holds.
In 2014, my husband and I engaged in the most intimate of acts: We blended our genes and created an embryo. This tiny human, now nine months old, is genetically half him and half me. We were hoping our daughter would get my looks and my husband's temperament; instead she seems to have inherited his pale skin and my pig-headedness. We supplied her genetic building blocks, but fate arranged them into a new being.
If we had waited a decade or two to procreate, we might've gained the upper hand on fate by picking and choosing genes to shape her physical features, her temperament, even her identity. This is the peril and promise of genetics. It's what makes the gene "one of the most powerful and dangerous ideas in the history of science," writes Pulitzer prize–winning author and cancer researcher Siddhartha Mukherjee. [Full disclosure: Mukherjee is working with VICE on a new initiative, to be announced in the coming months.]
In his new book, The Gene: An Intimate History, Mukherjee gives us a sweeping history of genetics—from the cockamamie ideas that preceded the birth of the field (e.g. sperm sculpt embryos out of menstrual blood) to our current attempts to decipher and manipulate the human genome, and finally a sometimes-terrifying picture of what the future holds.
Mukherjee begins with a peek at the skeletons in his own genetic closet: two uncles and a cousin crippled by mental illness. Their unraveling left an indelible mark on Mukherjee. "Scarcely a day passes in my adult life when I do not think about inheritance and family," he writes. When he met the woman who would become his wife, he warned her about the "splintered minds" in his family.
Mukherjee sprinkles brief personal interludes throughout the 500-page book, but he devotes the bulk of The Gene to a chronological history of the field. Some characters will be familiar from high school biology—Mendel, Darwin, Watson, Crick—but Mukherjee gives them new vigor and vastly expands the cast. The book often entertains, but this isn't a beach read. The middle sections, packed with the findings and technologies that propelled genetics into the modern era, can feel a bit like schoolwork. But those who don't mind slowing down to digest the concepts Mukherjee lays out will be rewarded with a deeper understanding of how the human recipe encoded in our cells gives rise to a human being.
The Gene also offers a window into the inner workings of science itself. Mukherjee gives us the breakthroughs, of course, but he also delves into the rivalries, the missteps, and the sometimes excruciating monotony of the experiments: In the early 1970s, a team of researchers including a young biologist named Robert Horvitz began trying to map the location of every cell in a worm's body in an attempt to understand the fate of each. "It was exhausting, hallucination-inducing work, 'like watching a bowl of hundreds of grapes' for hours at a time, Horvitz recalled, and then mapping each grape as it changed its position in time and space."
The book's finest bits deal with the impact of genetics on society: the Nazi eugenics program in Germany, for example, and the sterilization program in the US, which began carrying out tubal ligations of "feebleminded" women in the 1920s. One case, Buck v. Bell, made it all the way to the Supreme Court. In the majority opinion, Oliver Wendell Holmes Jr. wrote that it would be better to sterilize those who are "manifestly unfit" than "to execute degenerate offspring for crime, or to let them starve for their imbecility." These programs attempted to shape society's collectiveDNA by eliminating undesirables or their children.
No reasonable person would defend that kind of strategy today, but that doesn't mean we've stopped trying to shape the human genome. Far from it. Mukherjee points out that we already routinely test fetuses for Down syndrome and other serious genetic defects. Couples can choose to end a pregnancy on the basis of these tests. In the future, we'll undoubtedly have the ability to test for many more diseases. But most illnesses—cancer, for example—depend on a slew of genes and some sort of external trigger. These genes might predispose an individual to an outcome, but they aren't a guarantee. Should we eliminate a fetus or embryo because it's likely to develop cancer or schizophrenia? Or, to go onestep further, should we edit genes linked to disease? These kinds of scenarios can inspire "both wonder and a certain moral queasiness," Mukherjee writes. "Illness might progressively vanish, but so might identity."
We often describe genetic mutations as defects, but Mukherjee points out that a mutation is just a deviation from the norm. The defect or disease arises when a mutation creates a mismatch between an organism and its environment. "In the land of the blind, the sighted man is king. But flood that land with a toxic, blinding light—and the kingdom reverts to the blind," Mukherjee writes. So how do we decide as a society which mutations to eliminate and which to promote? And what will be the cost? These are the questions we'll have to address sooner rather than later. "The most remarkable fact about human genomic engineering today is not how far out of reach it is, but how perilously, tantalizingly near," Mukherjee writes.
I often find myself wondering what the future holds for my daughter. Will she be happy? Will she get sick? Will she have a long life? I might find some of the answers in her genes. But even if I could read the code, or rewrite it, I probably wouldn't. DNA might seem like destiny, but most genes don't dictate our path or our destination. They're more like a powerful wind, nudging us this way or that.
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