Honoring a Modern Mendel

By Claudia Wallis

Geneticist Barb McClintock, ignored for years, wins a Nobel

There was no morning call from Stockholm; Barbara McClintock does not have a phone. Instead, the 81-year-old geneticist learned the news by radio. "Oh, dear," she is said to have murmured. And having pronounced that judgment, the diminutive (5-ft., 100-lb.) scientist donned her usual attire--baggy dungarees, a man-tailored shirt and sturdy oxfords--and stepped out for her usual morning walk through the woods near Cold Spring Harbor Laboratory on Long Island. As usual, she gathered walnuts along the way. Winning the Nobel Prize for Medicine seemed no reason to alter her schedule.

That understated response to the greatest honor in science was typical of the intensely private, no-nonsense researcher. Genetics is a science founded by a monk--19th century Augustinian Gregor Mendel--and McClintock is in every sense his disciple. For half a century she has labored in almost monastic solitude over her patch of Indian corn, or maize, much as Mendel did in his famous pea patch. In an era when most scientific work is done by large research teams, McClintock did not even have a laboratory assistant. ("Excuse me for being hoarse," she once told a scientist who stopped by her lab at 5 p.m., "but I have not yet used my vocal cords today.") Also, like Mendel, McClintock received little attention for her efforts throughout most of her career. Her principal discovery was both complex and heretical: genes, she claimed, are not fixed on the chromosome like so many pearls on a string; they can move around in an unpredictable fashion. The trouble was that she announced this back in 1951, and as one Nobel committee member noted last week, "only about five geneticists in the world could appreciate it."

The world has finally begun to catch up with "Barb" McClintock. The Nobel Prize Committee hailed her once obscure work as "one of the two great discoveries of our times in genetics," the other being the 1953 discovery, by James Watson and Francis Crick, of the double-helix structure of DNA. In 82 years of Nobel history, just six other women have won honors in scientific categories; and only two of these were named alone, without fellow honorees: France's Marie Curie in 1911, for discovering radium and polonium, and Britain's Dorothy Crowfoot Hodgkin in 1964, for deciphering the structure of penicillin and other compounds. McClintock is the first to win unshared honors in medicine and physiology. Said Watson, who has been director at Cold Spring Harbor and hence McClintock's boss for 15 years: "It is not a controversial award. No one thinks of genetics now without the implications of her work."

McClintock's life has been a study in single-mindedness. The third of four children born to a Hartford doctor and his wife, she enrolled at Cornell University at 17, despite her mother's conviction that college was no place for a woman. Her intended major, plant breeding, was considered unsuitable for ladies, so McClintock settled for botany. She earned a doctorate in plant genetics in 1927 and began a lifelong romance with maize. Since tenured faculty positions were not available to women in the 1930s, McClintock bounced from job to job. She was unemployed in 1942, when the Carnegie Institution of Washington, B.C., came to her rescue and offered her a spot at its genetics lab in Cold Spring Harbor. She has been there ever since, grateful for the forbearance. "If I had been at some other place, I'm sure that I would've been fired for what I was doing," she noted last week, "because nobody was accepting it."

Indeed, though McClintock was elected to the National Academy of Sciences in 1944, only the third woman to win that honor, she soon fell from the graces of her peers. Her notion that genes could "jump" around on a chromosome flew in the face of scientific dogma. "They thought I was crazy, absolutely mad," she recalls. But the evidence was as plain as the ears on McClintock's beloved cornstalks. Years of painstaking planting, pollination and observation had taught her that color changes in the successive generations of maize did not follow predictable hereditary patterns. Her research led her to conclude that genes that govern the color of a kernel and other such characteristics can be turned on or off by genetic elements that act as switches, and that these genetic switches can move from one part of a chromosome to another, as commanded by a third type of element known as an "activator" (see diagram).

Since her ideas were met by general disbelief, McClintock virtually gave up publishing her results: "Nobody was reading me, so what was the use?" But in the 1960s, research conducted by high-tech molecular biologists began to confirm what McClintock had learned with old-fashioned Mendelian methods. The spunky geneticist was neither bitter nor surprised: "When you know you're right, you don't care what others think. You know sooner or later it will come out in the wash."

Today, McClintock's "jumping genes" have a secure place in biology. When bacteria develop resistance to an antibiotic, it is now known, they pass this characteristic on to neighboring bacteria via those "transposable elements," as McClintock has called them. They may also play a role in the transformation of normal cells into malignant ones, and in speeding up the process of evolution.

When recognition came to McClintock, it was an avalanche. In 1981 she won the prestigious $15,000 Albert Lasker Basic Medical Research Award as well as a $50,000 prize from Israel's Wolf Foundation and was named a fellow by the MacArthur Foundation of Chicago --a tribute that provides her with a tax-free income of $60,000 a year for life. Her reaction at the time: "Rather upset. I'm not a person who likes to accumulate things." But she did treat herself to a new Honda Accord and moved out of her austere home of 20 years -- two rooms over a garage -- and into more spacious quarters.

In the sole press conference she granted last week, McClintock said she had made no plans for the use of her Nobel winnings: "I don't even know what the award brings in." (It is $190,000.) But the energetic octogenarian has never lacked for things to do. Working in her corn patch, she says, "has been such a deep pleasure that I never thought of stopping, and I just hated sleeping. I can't imagine having a better life." Reluctantly, McClintock will take time off from that pleasure to collect her prize in Stockholm, and perhaps (Oh, dear!) to buy a suitably fancy dress.

With reporting by Dorothy Ferenbaugh, Mary Johnson This file is automatically generated by a robot program, so viewer discretion is required.