The Gene: An Intimate History - Siddhartha Mukherjee Page 0,53

higher bursts of energy.

In theory, this sounded simple; in practice, it was tricky. When Muller first tried exposing flies to X-rays, he killed them all. Frustrated, he lowered the dose—and found that he had now sterilized them. Rather than mutants, he had created vast flocks of dead, and then infertile, flies. In the winter of 1926, acting on a whim, he exposed a cohort of flies to an even lower dose of radiation. He mated the x-rayed males with females and watched the maggots emerge in the milk bottles.

Even a cursory look confirmed a striking result: the newly born flies had accumulated mutations—dozens of them, perhaps hundreds. It was late at night, and the only person to receive the breaking news was a lone botanist working on the floor below. Each time Muller found a new mutant, he shouted down from the window, “I got another.” It had taken nearly three decades for Morgan and his students to collect about fifty fly mutants in New York. As the botanist noted, with some chagrin, Muller had discovered nearly half that number in a single night.

Muller was catapulted into international fame by his discovery. The effect of radiation on the mutation rate in flies had two immediate implications. First, genes had to be made of matter. Radiation, after all, is merely energy. Frederick Griffith had made genes move between organisms. Muller had altered genes using energy. A gene, whatever it was, was capable of motion, transmission, and of energy-induced change—properties generally associated with chemical matter.

But more than the material nature of the gene, it was the sheer malleability of the genome—that X-rays could make such Silly Putty of genes—that stunned scientists. Even Darwin, among the strongest original proponents of the fundamental mutability of nature, would have found this rate of mutation surprising. In Darwin’s scheme, the rate of change of an organism was generally fixed, while the rate of natural selection could be amplified to accelerate evolution or dampened to decelerate it. Muller’s experiments demonstrated that heredity could be manipulated quite easily: the mutation rate was itself quite mutable. “There is no permanent status quo in nature,” Muller later wrote. “All is a process of adjustment and readjustment, or else eventual failure.” By altering mutation rates and selecting variants in conjunction, Muller imagined he could possibly push the evolutionary cycle into hyperdrive, even creating entirely new species and subspecies in his laboratory—acting like the lord of his flies.

Muller also realized that his experiment had broad implications for human eugenics. If fly genes could be altered with such modest doses of radiation, then could the alteration of human genes be far behind? If genetic alterations could be “induced artificially,” he wrote, then heredity could no longer be considered the unique privilege of an “unreachable god playing pranks on us.”

Like many scientists and social scientists of his era, Muller had been captivated by eugenics since the 1920s. As an undergraduate, he had formed a Biological Society at Columbia University to explore and support “positive eugenics.” But by the late twenties, as he had witnessed the menacing rise of eugenics in the United States, he had begun to reconsider his enthusiasm. The Eugenics Record Office, with its preoccupation with racial purification, and its drive to eliminate immigrants, “deviants,” and “defectives,” struck him as frankly sinister. Its prophets—Davenport, Priddy, and Bell—were weird, pseudoscientific creeps.

As Muller thought about the future of eugenics and the possibility of altering human genomes, he wondered whether Galton and his collaborators had made a fundamental conceptual error. Like Galton and Pearson, Muller sympathized with the desire to use genetics to alleviate suffering. But unlike Galton, Muller began to realize that positive eugenics was achievable only in a society that had already achieved radical equality. Eugenics could not be the prelude to equality. Instead, equality had to be the precondition for eugenics. Without equality, eugenics would inevitably falter on the false premise that social ills, such as vagrancy, pauperism, deviance, alcoholism, and feeblemindedness were genetic ills—while, in fact, they merely reflected inequality. Women such as Carrie Buck weren’t genetic imbeciles; they were poor, illiterate, unhealthy, and powerless—victims of their social lot, not of the genetic lottery. The Galtonians had been convinced that eugenics would ultimately generate radical equality—transforming the weak into the powerful. Muller turned that reasoning on its head. Without equality, he argued, eugenics would degenerate into yet another mechanism by which the powerful could control the weak.

While Hermann Muller’s scientific work was ascending to its zenith in Texas, his personal life