The Gene: An Intimate History - Siddhartha Mukherjee Page 0,33

instance of information flow—but if you looked deeply, squinting your conceptual lenses, it was easy to imagine information moving pervasively through the entire living world. The unfurling of an embryo; the reach of a plant toward sunlight; the ritual dance of bees—every biological activity required the decoding of coded instructions. Might Mendel, then, have also stumbled on the essential structure of these instructions? Were units of information guiding each of these processes? “Each of us who now looks at his own patch of work sees Mendel’s clues running through it,” Bateson proposed. “We have only touched the edge of that new country which is stretching out before us. . . . The experimental study of heredity . . . is second to no branch of science in the magnitude of the results it offers.”

The “new country” demanded a new language: Mendel’s “units of heredity” had to be christened. The word atom, used in the modern sense, first entered scientific vocabulary in John Dalton’s paper in 1808. In the summer of 1909, almost exactly a century later, the botanist Wilhelm Johannsen coined a distinct word to denote a unit of heredity. At first, he considered using de Vries’s word, pangene, with its homage to Darwin. But Darwin, in all truth, had misconceived the notion, and pangene would always carry the memory of that misconception. Johannsen shortened the word to gene. (Bateson wanted to call it gen, hoping to avoid errors in pronunciation—but it was too late. Johannsen’s coinage, and the continental habit of mangling English, were here to stay.)

As with Dalton and the atom, neither Bateson nor Johannsen had any understanding of what a gene was. They could not fathom its material form, its physical or chemical structure, its location within the body or inside the cell, or even its mechanism of action. The word was created to mark a function; it was an abstraction. A gene was defined by what a gene does: it was a carrier of hereditary information. “Language is not only our servant,” Johannsen wrote, “[but] it may also be our master. It is desirable to create new terminology in all cases where new and revised conceptions are being developed. Therefore, I have proposed the word ‘gene.’ The ‘gene’ is nothing but a very applicable little word. It may be useful as an expression for the ‘unit factors’ . . . demonstrated by modern Mendelian researchers.” “The word ‘gene’ is completely free of any hypothesis,” Johannsen remarked. “It expresses only the evident fact that . . . many characteristics of the organism are specified . . . in unique, separate and thereby independent ways.”

But in science, a word is a hypothesis. In natural language, a word is used to convey an idea. But in scientific language, a word conveys more than an idea—a mechanism, a consequence, a prediction. A scientific noun can launch a thousand questions—and the idea of the “gene” did exactly that. What was the chemical and physical nature of the gene? How was the set of genetic instructions, the genotype, translated into the actual physical manifestations, the phenotype, of an organism? How were genes transmitted? Where did they reside? How were they regulated? If genes were discrete particles specifying one trait, then how could this property be reconciled with the occurrence of human characteristics, say, height or skin color, in continuous curves? How does the gene permit genesis?

“The science of genetics is so new that it is impossible to say . . . what its boundaries may be,” a botanist wrote in 1914. “In research, as in all business of exploration, the stirring time comes when a fresh region is unlocked by the discovery of a new key.”

Cloistered in his sprawling town house on Rutland Gate, Francis Galton was oddly unstirred by the “stirring times.” As biologists rushed to embrace Mendel’s laws and grapple with their consequences, Galton adopted a rather benign indifference to them. Whether hereditary units were divisible or indivisible did not particularly bother him; what concerned him was whether heredity was actionable or inactionable: whether human inheritance could be manipulated for human benefit.

“All around [Galton],” the historian Daniel Kevles wrote, “the technology of the industrial revolution confirmed man’s mastery of nature.” Galton had been unable to discover genes, but he would not miss out on the creation of genetic technologies. Galton had already coined a name for this effort—eugenics, the betterment of the human race via artificial selection of genetic traits and directed breeding of human carriers. Eugenics was merely an