Read The Violinist's Thumb: And Other Lost Tales of Love, War, and Genius, as Written by Our Genetic Code for Free Online Page B

arena. In autumn 1909, he filled in for a colleague on sabbatical and taught the only introductory course of his Columbia career. And during that semester he made, one observer noted, “his greatest discovery,” two brilliant assistants. Alfred Sturtevant heard about Morgan’s class through a brother who taught Latin and Greek at Columbia, and although just a sophomore, Sturtevant impressed Morgan by writing an independent research paper on horses and the inheritance of coat color. (Morgan hailed from Kentucky, and his father and uncle had been famous horse thieves behind Union lines during the Civil War, leading a band known as Morgan’s Raiders. Morgan scorned his Confederate past, but he knew his horses.) From that moment on, Sturtevant was Morgan’s golden boy and eventually earned a coveted desk in the fly room. Sturtevant cultivated a cultured air, reading widely in literature and doing trickier British crossword puzzles—although, amid the fly room’s squalor, someone also once discovered a mummified mouse in his desk. Sturtevant did have one deficiency as a scientist, red-green color blindness. He’d tended horses on the family fruit farm in Alabama largely because he proved useless during harvest, struggling to spot red strawberries on green bushes.
    The other undergrad, Calvin Bridges, made up for Sturtevant’s poor eyesight, and his stuffiness. At first Morgan merely took pity on Bridges, an orphan, by giving him a job washing filth from milk bottles. But Bridges eavesdropped on Morgan’s discussions of his work, and when Bridges began spotting interesting flies with his bare eyes (even through the dirty glass bottles), Morgan hired him as a researcher. It was basically the only job Bridges ever had. A sensuous and handsome man with bouffant hair, Bridges practiced free love
avant la lettre.
He eventually abandoned his wife and children, got a vasectomy, and started brewing moonshine in his new bachelor lair in Manhattan. He proceeded to hit on—or flat-out proposition—anything in a skirt, including colleagues’ wives. His naive charm seduced many, but even after the fly room became legendary, no other university would blacken its reputation by employing Bridges as anything but a measly assistant.

    Playboy Calvin Bridges (
left
) and a rare photo of Thomas Hunt Morgan (
right
). Morgan so detested having his picture taken that an assistant who once wanted one had to hide a camera in a bureau in the fly lab and snap the photo remotely by tugging a string. (Courtesy of the National Library of Medicine)
    Meeting Bridges and Sturtevant must have cheered Morgan, because his experiments had all but flopped until then. Unable to find any natural mutants, he’d exposed flies to excess heat and cold and injected acids, salts, bases, and other potential mutagens into their genitals (not easy to find). Still nothing. On the verge of giving up, in January 1910 he finally spotted a fly with a strange trident shape tattooed on its thorax. Not exactly a de Vriesian über-fly, but something. In March two more mutants appeared, one with ragged moles near its wings that made it appear to have “hairy armpits,” another with an olive (instead of the normal amber) body color. In May 1910 the most dramatic mutant yet appeared, a fly with white (instead of red) eyes.
    Anxious for a breakthrough—perhaps this was a mutation period—Morgan tediously isolated white-eyes. He uncapped the milk bottle, balanced another one upside down on top of it like mating ketchup bottles, and shined a light through the top to coax white-eyes upward. Of course, hundreds of other flies joined white-eyes in the top bottle, so Morgan had to quickly cap both, get a new milk bottle, and repeat the process over and over, slowly dwindling the number with each step, praying to God white-eyes didn’t escape meantime. When he finally, finally segregated the bug, he mated it with red-eyed females. Then he bred the descendants with each other in