Crossing the Germline

Marcy Kelly’s “Double Spiral” depicts a world firmly rooted in today’s debates over genetic editing.

Scientists looking at DNA maps
Franco Zacharzewski

An expert on the ethical, legal, and policy implications of biomedical technologies responds to Marcy Kelly’s “Double Spiral.”

In Marcy Kelly’s story “Double Spiral,” genetic technology, in the hands of companies and hackers, goes wrong. It starts out, worryingly, with a private company holding gigantic amounts of genetic and health data on 60 percent of the U.S. population, with the ability to infer it for the rest of the country. Then, biohackers weaponize gene-editing technologies, causing the death of a senator, while a new genetic mutation known as “K5” accidentally enters the gene pool. The mutation causes Zika-like cognitive and physical disabilities in children. Although it’s a science fiction dystopia, flying ahead to a future in which video billboards are personalized to passersby, Kelly’s world is firmly rooted in today’s.

Primarily as a result of our seemingly benign interest in family trees, several U.S. companies have already amassed proprietary databases of DNA from 26 million customers. There are an estimated 15 million samples in Ancestry’s database, while 23andMe says it has tested 10 million customers. Having learned that a minority of traits, such as Huntington’s disease or cystic fibrosis, can be explained by single genetic differences, scientists are now bringing big data approaches to genome sequencing to calculate “polygenic risk scores” quantifying the likelihood that people will develop schizophrenia, graduate from high school, or score highly on IQ tests. In 2012, CRISPR-Cas9, a new technique for efficiently altering DNA, was discovered. A few years later, a group of college students competing in a synthetic biology competition nearly created something called a gene drive, which forces a specific gene, or genes, to spread quickly through a population and can wreak havoc if accidentally or intentionally released. Meanwhile the FBI, the Pentagon, and the U.N. bioweapons office have quietly held meetings to talk through the ways in which CRISPR could be weaponized. And where in Kelly’s world, disabled children are abandoned on the subway, several infants born over the past few years under international surrogacy arrangements have remained in their birth countries, uncollected by their intended parents.

The K5 genetic mutation at the center of Kelly’s story resonates with some of today’s thorniest issues, echoing the birth last year of twin girls whose DNA had been intentionally altered in ways that would be passed on to future generations. In Kelly’s story, the protagonist, Rada, discovers 15 years after the fact that the disability-causing mutation had been accidentally introduced into the gene pool through regional water supplies and then monetized to sell preconception and prenatal testing kits.

The real world’s first gene-edited babies, kept secret until after they were born, were intended to be an internationally acclaimed public health triumph worthy of the Nobel Prize. Instead, the experiment was roundly condemned as an example of unethical research driven by scientific hubris. Where in Kelly’s story K5 is clearly a deleterious genetic change, it will be decades before we know whether these real-world infants have been helped or harmed. What is clear, however, is that a previous commitment to thoroughly airing moral and ethical concerns before proceeding with germline modification has given way to the expediencies of technological development.

News of the gene-edited babies broke on Nov. 25, 2018, just two days before the second international genome editing summit was due to begin in Hong Kong. The scientist, He Jiankui of Southern University of Science and Technology in Shenzhen, had completed a Ph.D. and a postdoc in the U.S. before returning to China. His study involved eight male-female couples in which the man was HIV-positive. While standard assisted reproductive procedures can help men reproduce without passing the virus on to the mother or the child, He offered to go one step further: Babies of the couples in the study would be born free from the virus and with built-in immunity to it. HIV and AIDS are stigmatized and poorly managed conditions in China, He reasoned—suffering these families know firsthand.

Edited embryos were transferred to the intended mothers for gestation, leading to the birth of twin girls in October 2018 and a second pregnancy about which no further news has been heard. While one of the babies was mosaic for the genetic change—meaning the DNA in only some of her cells had been successfully changed—He described the pregnancy as normal and both infants as healthy.

Rather than praising the experiment, as He had hoped, prominent scientists from around the world called it “premature” and an “epic scientific misadventure.” The organizing committee for the second summit, at which He spoke to explain and defend his work, labeled the experiment “irresponsible” and said it “failed to conform with international norms.”

Until this moment, there had appeared to be broad international agreement, based on decades of conversation, that modifying the genomes of human sperm, eggs, or embryos was a line not to be crossed. Reasons not to cross this line included: the technical difficulty of calculating the risk-benefit ratio for an experiment that will affect future generations, the concern that germline modification would lead to human enhancement or increased inequality, and the idea that the human genome is inviolable, whether because it is a sacred gift from God or because it belongs to all of humanity, including future generations. Many nations, including the U.K., Canada, Australia, Brazil, and a number of countries in Europe, passed laws prohibiting germline modification in humans, codifying this apparent international consensus into national law.

At the conclusion of the first international summit on genetic editing, in December 2015, the organizing committee stuck to this perspective, noting that any future attempt to do germline modification would need to overcome a number of hurdles, including “the moral and ethical considerations in purposefully altering human evolution,” about which the committee said there ought to first be “broad societal consensus.”

Just three years later, rather than tackling these difficult ethical and democratic questions, the organizing committee for the second international summit emphasized safety (an admittedly tricky question for an intervention intended to have intergenerational effects, but certainly not the sole concern here). Germline editing remains too risky to test in humans right now due to “scientific understanding and technical requirements,” the committee concluded. To address these problems, it called for the development of “a rigorous, responsible translational pathway toward such trials.” No mention was made of unresolved ethical, moral, or societal considerations.

This is not to say that we are headed toward a future in which a K5-like mutation could intentionally or even accidentally be pushed into the human gene pool. Humans are relatively slow to reproduce and most of us have just one or two children; the genetic changes made in the Chinese experiments, whether beneficial or harmful, would need to be widely available before they could have an impact at the population level. The point is that we are adopting a worldview that sees humans, including future generations, as mutable in much the same ways that Kelly depicts. This worldview has little time for “the moral and ethical considerations in purposefully altering human evolution,” let alone concerns about “playing God,” going “against Nature,” or contravening “human dignity.” Instead it is focused on quantifiable characteristics and measurable outcomes. Rada marvels at LyfeCode’s ability “to know everything about someone without knowing anything about them,” a phrase that reduces persons to their genomes, incomes, and “a billion biological characteristics.” Then she falls victim to it, and ultimately disappears.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.