Chapter 1: The New Biology
16 - Time’s Flies
As the century began—although there was broad acceptance of Darwin’s view that natural selection produced gradual evolution—a nagging problem remained. The theory was incomplete without an explanation for heredity. Into that setting burst the rediscovery of Gregor Mendel.
Working in obscurity some fifty years before, the patient monk had tracked inherited traits in generation upon generation of pea plants. If his methods were simple, their impact would be nonetheless vital. For the first time, basic principles governing heredity were laid bare. And one of those principles seemed to be that change occurred in discrete jumps, not by Darwin’s gradual evolution. This was a problem for Darwinists.
In the new century, Mendel’s champion was William Bateson. A zoologist, Bateson coined the term “genetics”—though no one yet knew what genes were—and worked to extend Mendel’s insight into animals. To that end he culled examples of what were later termed “hopeful monsters.” Those were cases where, for instance, a fly’s wing might grow where a leg should be. His aim was to prove that, just as in peas, hereditary change in animals advanced in sudden small jumps. The appearance of one of those jumps was first documented in New York, in a Columbia University lab—the famous “fly room” of Thomas Hunt Morgan. Patiently tracking heredity through many generations of black-eyed fruit flies, Morgan witnessed the sudden appearance of one with white eyes. With time he would go on to establish that there were in fact genes; that whatever they were, they were located in the chromosomes of the cell’s nucleus; and that they were the carriers of heredity.
While this was important work, not everyone was pleased with Morgan’s flies. They would relegate supporters of Darwin’s “gradual change” to something like obscurity for the next two decades. The view of nature as a machine was once more on the rise.
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