'Single Gene May Hold Key to Life Itself'

dna structure
dna structure

"Your IQ depends on a single gene"; "Long life is all in the genes"; "A gene that could explain why the red mist descends"; "Sleeping is all in the genes"; "Scientists ID morning person gene"; "The Twitter gene."

Those are real, published headlines. Up until the last one, I'd forgive you for thinking they appeared in the 1910s, rather than the 2010s. Contemporary science has a far more sophisticated understanding of genetics than a century ago -- and complexity is one of its central features. We know nothing is "all in the genes," let alone one gene. Why then do such headlines persist?

If, as Evelyn Fox Keller wrote, the 20th century was "the century of the gene," the 21st is shaping up very differently. In the biomedical journals, genetic determinism is out -- no one in the labs believes any more in "the gene for" anything interesting. Even diseases that behave like single-gene conditions turn out to be more complicated than we had thought. In short, genes contribute probabilities, not certainties. Indeed, genes themselves are somewhat probabilistic. A century ago, geneticists thought of genes as beads on a string, each one somehow producing a trait. Now they think of them as complex domains, fragmented and distributed around the chromosomes, modulated by other genes and responsive to the environment. What's more, the once-inviolable border between genes and environment is crumbling. The burgeoning field of epigenetics has revived the old, discredited notion of the inheritance of acquired characteristics. We now understand that the genome responds to and reversibly stores information gathered from experience. It is truly, as the iconic plant geneticist Barbara McClintock once said, "a sensitive organ of the cell."

Lay understanding isn't keeping pace with the science. By the time it reaches the public eyeball, the subtle, interactive genome has devolved into some kind of runic textbook. Some of this degradation can be explained by the challenges and politics of science popularization. Scientific knowledge flows through a branching set of information pipes: as it moves from lab notebook to press release to newspaper article to blog post, nuances and complexity tend to be lost.

The debacle over the recent announcement of the completion of the ENCODE project illustrates both the delicious complexity of the genome and the hazards of over-simplification. Never mind the details, but ENCODE is a sort of specialized human genome project that looks specifically at genome regions that aren't genes but are functional. No one seriously doubts that the project is valid and important. But on Sept. 5, Ewan Birney, the project's director, issued a press release that was just a bit sensational, defining "functional" in a generous way that made the project sound slightly epochal. Journalists picked up Birney's statements and turned them into the "discovery" that so-called junk DNA is actually functional, producing headlines such as, "Breakthrough study overturns theory of 'junk DNA.' Distortions leaked in to the ENCODE study at every stage in the information pipe. The result was a science-writing trainwreck whose brightest side is a series of reflective postmortems, on such blogs as Sandwalk and Ars Technica.

But distortions and sensationalism really only explain how deterministic stories persist -- not why. There must be something satisfying and lucrative about "gene-for" stories. What is so sexy about a gene for IQ?

I suggest that deterministic explanations help satisfy our urge to control. In 1945, the cybernetics pioneer Norbert Wiener wrote, "The intention and the result of a scientific inquiry is to obtain an understanding and a control of some part of the universe." That vision holds true for genetic medicine as much as any other branch of science. We have a molecular vision of life, said the historian Lily Kay. Molecular biomedicine seeks to identify the mechanisms of disease -- and the mechanisms of health -- and to manipulate them, for both the individual and the greater good.

Until fairly recently, the effort to prevent and eliminate genetic disease -- and to identify and enhance the genetic components of health -- was called "eugenics." A century ago, eugenics was embedded in Progressive-era notions of population and state control. As is well-known, horrendous infractions of human rights -- especially reproduction -- were committed on grounds of a modern scientific approach to the amelioration of man. In the 1950s and 1960s, physicians and scientists stopped using the term, reluctantly. Eugenics, they thought, was a noble project, subverted. But recently, a few scientists have bravely floated the suggestion that we reopen a discussion of eugenics -- without the notions of nationhood and state and population control that so stained earlier efforts. They argue that eugenics is acceptable -- even desirable -- if it can be individualized. Personalized. Liberalized.

If eugenics is disentangled from state, nation, and population, we are left with an impulse that transcends political styles, cultural trends, and governmentality. An impulse to reduce suffering, now and in the future. A humanitarian impulse to control destiny. An impulse to be healthier, smarter, happier. And taller? And perhaps more successful?

Numerous sociologists, philosophers, scientists, and ethicists -- among the most nuanced is Nikolas Rose -- have argued that we are inching toward an entirely new relationship toward life, one in which to be alive is to be manipulable, engineerable. This was precisely the dream of the eugenicists a century ago. Then, "hereditary" meant "unchangeable." Increasingly, it means precisely the opposite. Our power to control is reaching even realms once synonymous with uncontrollable.

The sensational gene-for headlines, then, persist because the promises of genetic medicine persist. Indeed, it seems that the more complex biology becomes, the more we yearn for simple explanations. We will always hanker for the single gene that explains IQ, the one food item that melts away belly fat, the secret trick that reverses aging. Determinist headlines are expressions of hope -- and hope has always been one of the main products of medicine.