'Single Gene May Hold Key to Life Itself'

"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...