Science: The Secret of Life

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Nebraska Farm Boy. These basic facts of genetics were becoming known about the time Geneticist George Beadle was born in 1903. His father ran a small, progressive farm near Wahoo, Neb. (1900 pop. 900). His mother died when he was four, leaving him, his brother and sister to be mothered, after a fashion, by a succession of hired housekeepers. He remembers farm life in general with pleasure, but he still dislikes cream because he had to skim it off endless milk pans.

Wahoo was not noted for learning half a century ago, but its less-than-perfect school system did not slow or discourage Beadle's active mind. He made his own lunch, generally jelly sandwiches (he still hates jelly sandwiches) and walked the three-mile round trip to school. When he earned a little money by such rural operations as keeping bees and trapping muskrats, he bought garlic bolognas (two for 5¢) at the Bohemian butcher shop.

Beadle might be a farmer today if the Wahoo high school had not had a teacher, Miss Bess McDonald, with the gift of infectious enthusiasm. She taught physics and chemistry, and young George fell in love with both her and her sciences. He spent long evenings at her house, wrapped in his schoolboy crush, and listened to her attempts to convert him to an unusual religious sect whose name he does not remember. He never hit the sawdust trail, but when Miss McDonald's religious appeals failed, she started persuading him to go to college. His father expected him to take over the farm, but Bess McDonald headed him for the University of Nebraska's College of Agriculture at Lincoln. A small inheritance helped, and father Beadle made no objection.

The Fruit Flies. Beadle entered college in 1922. At the time, genetics was still a small, specialized field, but it was growing in both importance and intellectual vogue. Its great man was Professor Thomas Hunt Morgan of Columbia University, founder of the "fly school'' of genetics. He worked with Drosophila melanogaster, the small fly that congregates around fruit stands and garbage pails. As living instruments of genetics they were a happy choice. They are only 1/12 in. long, so their board bill is low. They produce new generations in about two weeks, multiplying rapidly in cream bottles stoppered with wads of gauze. They are easily come by; when a geneticist wants wild "genotype" flies, he puts a banana on the windowsill, and the genotypes come unbidden.

In large populations of fruit flies, a few are apt to be naturally defective, with stunted wings or misshapen limbs. In some cases these defects are inherited in a Mendelian manner, like the color of Mendel's flowers. Some traits are dominant, others recessive. They are caused by mutations (damaged genes) in the flies' chromosomes (they have only four pairs), and Morgan's method was to study every possible way that mutations could be passed from generation to generation.