A short history of nearly everything - Bill Bryson [202]
Working out of a small lab (which became known inevitably as the Fly Room) in Schermerhorn Hall at Columbia University in New York, Morgan and his team embarked on a program of meticulous breeding and crossbreeding involving millions of flies (one biographer says billions, though that is probably an exaggeration), each of which had to be captured with tweezers and examined under a jeweler's glass for any tiny variations in inheritance. For six years they tried to produce mutations by any means they could think of—zapping the flies with radiation and X-rays, rearing them in bright light and darkness, baking them gently in ovens, spinning them crazily in centrifuges—but nothing worked. Morgan was on the brink of giving up when there occurred a sudden and repeatable mutation—a fly that had white eyes rather than the usual red ones. With this breakthrough, Morgan and his assistants were able to generate useful deformities, allowing them to track a trait through successive generations. By such means they could work out the correlations between particular characteristics and individual chromosomes, eventually proving to more or less everyone's satisfaction that chromosomes were at the heart of inheritance.
The problem, however, remained the next level of biological intricacy: the enigmatic genes and the DNA that composed them. These were much trickier to isolate and understand. As late as 1933, when Morgan was awarded a Nobel Prize for his work, many researchers still weren't convinced that genes even existed. As Morgan noted at the time, there was no consensus “as to what the genes are—whether they are real or purely fictitious.” It may seem surprising that scientists could struggle to accept the physical reality of something so fundamental to cellular activity, but as Wallace, King, and Sanders point out in Biology: The Science of Life (that rarest thing: a readable college text), we are in much the same position today with mental processes such as thought and memory. We know that we have them, of course, but we don't know what, if any, physical form they take. So it was for the longest time with genes. The idea that you could pluck one from your body and take it away for study was as absurd to many of Morgan's peers as the idea that scientists today might capture a stray thought and examine it under a microscope.
What was certainly true was that something associated with chromosomes was directing cell replication. Finally, in 1944, after fifteen years of effort, a team at the Rockefeller Institute in Manhattan, led by a brilliant but diffident Canadian named Oswald Avery, succeeded with an exceedingly tricky experiment in which an innocuous strain of bacteria was made permanently infectious by crossing it with alien DNA, proving that DNA was far more than a passive molecule and almost certainly was the active agent in heredity. The Austrian-born biochemist Erwin Chargaff later suggested quite seriously that Avery's discovery was worth two Nobel Prizes.
Unfortunately, Avery was opposed by one of his own colleagues at the institute, a strong-willed and disagreeable protein enthusiast named Alfred Mirsky, who did everything in his power to discredit Avery's work—including, it has been said, lobbying the authorities at the Karolinska Institute in Stockholm not to give Avery a Nobel Prize. Avery by this time was sixty-six years old and tired. Unable to deal with the stress and controversy, he resigned his position and never went near a lab again. But other experiments elsewhere overwhelmingly supported his conclusions, and soon the race was on to