Time, Love, Memory: A Great Biologist and His Quest for the Origins of Behavior by Jonathan Weiner, Alfred A. Knopf, $27.50. 300 pages.




The News & Observer


August 29, 1999

Is biology our destiny?

The Harvard biologist Edward O. Wilson created a furor in 1975 when he speculated that genes play an important role in determining the behavior of animals (including humans). His book, "Sociobiology: The New Synthesis," rekindled the nature-versus-nurture war at a time when most sociologists thought nurture had won and when suggestions to the contrary were considered politically incorrect. The notion that genes make the person, his critics howled, is the idea used by ruling groups to justify existing privileges according to class, race or sex. In the overheated atmosphere of 1970's academia, genetic determinism was political dynamite.

Linked unfairly to racism and eugenics, Wilson was picketed by students, assailed by colleagues, and shunned in his own department. Ironically, while he was being cudgeled during the 1970s, a group of brash young molecular biologists were proving him correct, demonstrating the genetic basis of some types of behavior. Thanks to their work, 25 years later, Wilson's controversial theories have become more mainstream.

Pulitzer prize-winning science writer Jonathan Weiner tells these biologists' story in the best popular-science book so far this year. His account is extraordinarily well written and meticulously researched. And the story of how molecular biologists are exploring the way genes affect behavior should fascinate anyone who wants to understand "Time, Love, Memory."

The tale starts at Columbia University in 1907, when zoology professor Thomas Hunt Morgan began blasting fruit flies with X-rays and other mutagens - heat, light, chemicals, anything that might alter genes - to speed up evolution. After two years, a mutant appeared: instead of the brilliant red eyes of a normal fruit fly, the mutant had white eyes. Morgan used the mutant to breed a strain of white-eyed flies. Even today, Weiner writes, some molecular biologists still say, "In the beginning there was 'white.' " By breeding the mutants with normal flies, Morgan deduced that the gene which determined a fly's eye color was on the X chromosome. (Like human beings, female fruit flies have two X chromosomes; males have one X and one Y.) Later, Morgan and one of his graduate students, Alfred Sturtevant, located mutant genes on the fruit fly's chromosomes, thus creating the first gene map. Morgan won the Nobel Prize for his work, and he shared the prize money with Sturtevant.

While Morgan had shown that genes control physical characteristics, other scientists wondered whether they also influenced behavior. Weiner tracks this research by focusing on Seymour Benzer, a brilliant physicist who converted to biology after reading Erwin Schrodinger's 1944 book, "What Is Life?" Schrodinger was a Nobel Prize-winning physicist who attempted to join atomic physics with genetics to create a new science, which would later be called molecular biology. Schrodinger believed that "the secret of life is nothing more than a kind of clockwork." Both James Watson and Francis Crick, who later unraveled the double-helical structure of DNA, were mightily impressed by the book (as was the young E.O. Wilson) and, like Benzer, devoted themselves to molecular biology.

Following Morgan's lead, Benzer, chose fruit flies as his experimental subjects. In 1966, he set up his own Fly Room at Cal Tech in Pasadena, California. Fruit flies bear little resemblance to the common housefly. They don't bite, and they're much smaller, no bigger than an asterisk. Their size, short life cycle, and small number of genes (only 15,000 compared to 70,000 for a human) makes them ideal for biological experiments.

Consequently, Benzer selected fruit flies for his research and established his own Fly Room. Today, after Morgan's and Benzer's trailblazing work, almost all major universities have Fly Rooms. Fruit flies belong to the genus Drosophila, which means "lover of dew." The name is appropriate because the flies always emerge from their pupal cases at dawn, and adults invariably wake up at dawn to drink when the dew is heaviest. Like clockwork, normal fruit flies also take a siesta in the afternoon,and sleep through the night - even in the total darkness of a lab, even if they've never seen the sun, even if their ancestors have never seen the sun.

Benzer induced mutations in his flies by feeding them a mutagen called EMS. His team of graduate and postdoctoral students produced a stream of mutated flies. But while Morgan could change eye color Benzer and his students tried to produce mutants that lacked a sense of time, that were born earlier or later than normal, that didn't know when to wake up or when to sleep. Eventually, they produced flies that looked exactly like their normal brethren but exhibited no regular cycles of sleeping and waking. Next, they located the mutated gene, which was later named the "period" gene. By changing one gene, Benzer had dramatically altered the behavior of a fruit fly, disrupting an ancient pattern shaped by countless centuries of evolution.

Using the same techniques, Benzer's lab and others around the world produced and named other mutants with changed patterns of behavior. "Fruitless," was a male fly that never copulated and preferred the company of males. "Dunce" was a low I.Q. fly that couldn't remember how to avoid a shock that normal flies quickly learned to dodge. (This experiment also proved that fruit flies can learn!) Benzer and his colleagues had changed the flies behavior regarding time, love, and memory. Following their lead, researchers have now engineered genes in mice to produce alcoholic mice, monogamous mice, polygamous mice, and mice that are subject to seizures. As far as molecular biologists are concerned, the nature vs. nurture war is over - and nature has won. Many of them also believe that the work started by Benzer will one day help us understand the genetic underpinnings of human behavior. "My feeling," one biologist said with characteristic hubris, "is that molecular biologists are going to move into psychology and take over the field."

The behavioral psychologists that followed Sigmund Freud's pioneering work in psychology distanced themselves from nature: John Watson (no relation to James Watson) made the much-quoted claim that if he were given a dozen healthy babies, he would "guarantee to take one at random and train him" for any job, no matter what "his talents, penchants, tendencies, abilities, vocations, and the race of his ancestors." Obviously, Watson never encountered one of Benzer's mutant flies. By genetically changing those flies, Benzer proved the opposite: Genes control the flies' ability to tell time, make love and remember the past - and no amount of training can override those genetic instructions.

Weiner is careful not to extend genetic determinism to human behavior, which is affected by a larger and more complex array of genes. I suspect (as do many others) that both the molecular biologists and the behavioral psychologists are partially right. Both nature and nurture are important in determining the behavior of a human being.

E.O. Wilson, who survived the stones hurled at him in the 1970s, is cautious: "people," he wrote in his autobiography, "have free will and the choice to turn in many directions." Nevertheless, he believes that molecular biologists are providing the foundation for his much-maligned sociobiology synthesis. "Better Benzer than Freud!" he says. "Quote me. Better Benzer than Freud."

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