hoped to attempt another variation of the experiment—this time, he expected, with much higher efficiency and fidelity. He was not exaggerating: the technology to modify the genome of a human embryo may be complex, inefficient, and inaccurate—but it does not lie out of scientific reach.
While scientists in the West continue to watch Junjiu Huang’s experiments on human embryos with justified apprehension, Chinese scientists are far more sanguine about such experiments. “I don’t think China wants to take a moratorium,” one scientist reported in the New York Times in late June 2015. A Chinese bioethicist clarified, “Confucian thinking says someone becomes a person after they are born. That is different from the United States and other countries with a Christian influence, where because of religion they may feel research on embryos is not okay. Our ‘red line’ here is that you can only experiment on embryos that are younger than fourteen days old.”
Another scientist wrote of the Chinese approach, “Do first, think later.” Several public commentators seemed to agree with this strategy; in the comments section of the New York Times, readers advocated lifting the bans on human genomic engineering and urged a ramp-up in experimentation in the West, in part to remain competitive with the efforts in Asia. The Chinese experiments had evidently raised the stakes throughout the world. As one writer put it, “If we don’t do this work, China will.” The drive to change the genome of a human embryo has turned into an intercontinental arms race.
As of this writing, four other groups in China are reportedly working on introducing permanent mutations in human embryos. By the time this book is published, I would not be surprised if the first successful targeted genome modification of a human embryo had been achieved in a laboratory. The first “post-genomic” human might be on his or her way to being born.
We need a manifesto—or at least a hitchhiker’s guide—for a post-genomic world. The historian Tony Judt once told me that Albert Camus’s novel The Plague was about the plague in the same sense that King Lear is about a king named Lear. In The Plague, a biological cataclysm becomes the testing ground for our fallibilities, desires, and ambitions. You cannot read The Plague except as a thinly disguised allegory of human nature. The genome is also a testing ground for our fallibilities and desires, although reading it does not require understanding allegories or metaphors. What we read and write into our genome is our fallibilities, desires, and ambitions. It is human nature.
The task of writing that complete manifesto belongs to another generation, but perhaps we can scribe its opening salvos by recalling the scientific, philosophical, and moral lessons of this history:
1. A gene is the basic unit of hereditary information. It carries the information needed to build, maintain, and repair organisms. Genes collaborate with other genes, with inputs from the environment, with triggers, and with random chance to produce the ultimate form and function of an organism.
2. The genetic code is universal. A gene from a blue whale can be inserted into a microscopic bacterium and it will be deciphered accurately and with nearly perfect fidelity. A corollary: there is nothing particularly special about human genes.
3. Genes influence form, function, and fate, but these influences typically do not occur in a one-to-one manner. Most human attributes are the consequence of more than one gene; many are the result of collaborations between genes, environments, and chance. Most of these interactions are nonsystematic—i.e., they occur through the intersection between a genome and fundamentally unpredictable events. And some genes tend to influence only propensities and tendencies. We can thus reliably predict the ultimate effect of a mutation or variation on an organism for only a minor subset of genes.
4. Variations in genes contribute to variations in features, forms, and behaviors. When we use the colloquial terms gene for blue eyes or gene for height, we are really referring to a variation (or allele) that specifies an eye color or height. These variations constitute an extremely minor portion of the genome. They are magnified in our imagination because of cultural, and possibly biological, tendencies that tend to amplify differences. A six-foot man from Denmark and a four-foot man from Demba share the same anatomy, physiology, and biochemistry. Even the two most extreme human variants—male and female—share 99.688 percent of their genes.
5. When we claim to find “genes for” certain human features or functions, it is by virtue of defining that feature narrowly. It makes sense