It’s the End of the Gene As We Know It

We’ve all seen the stark headlines: “Being Rich and Successful Is in Your DNA” (Guardian, July 12); “A New Genetic Test Could Help Determine Children’s Success” (Newsweek, July 10); “Our Fortunetelling Genes” make us (Wall Street Journal, Nov. 16); and so on.

The problem is, many of these headlines are not discussing real genes at all, but a crude statistical model of them, involving dozens of unlikely assumptions. Now, slowly but surely, that whole conceptual model of the gene is being challenged.

We have reached peak gene, and passed it.

It is, of course, an impressive story. Today, most people know about Gregor Mendel’s breeding experiments with pea plants in the 1850s. He concentrated on simple traits with well-defined, easy to count variations: purple or white flowers; long or short stems; smooth or wrinkled seeds; and so on. After cross-fertilization the patterns of variation in offspring suggested correlations with variation in single “heredity units.”

Mendel’s inherited factors—hitherto imputed, but unidentified—are what came to be called the genes. In the early 1900s...