"Am I not a fly like thee? Or art thou not a man like me?" Jonathan Weiner uses part of Blake's "The Fly" as the epigraph to his new book, Time, Love, Memory. He reveals how the old nature-versus-nurture debate has come of age, at least for the fruit fly, placing genetic determinism on a pedestal. The book also carries as a subtext a depiction of laboratory life and takes as its central character the tenacious, eccentric Professor Seymour Benzer, darting off into his relationships with many of the key figures behind the genetic revolution.
Benzer works at night and many years ago he chose to use tiny flies called drosophila as a model to link genes and behaviour. Drosophila have an amazingly fast generation time; in ten days a new animal can be born, mature and propagate. With some 15,000 genes, they occupy an intermediate space between the lowliest self-perpetuating life forms (bacteria) and the highest (mammals). For many scientists they are the ideal model to use in understanding how humans develop.
In fashionable scientific fields opportunists are quick to jump on any passing bandwagon. Watson, Crick and many of the other official champions of molecular biology emerge with little credit from Weiner's account. Benzer, a timid pioneer, dodged conflict by roaming from one obscure backwater to another. At each stop he would stir up new and bigger fish, only to move on once the sharks arrived to fight over his legacy. Eventually he showed that, just like eye colour and other physical characteristics, sleep-wake patterns, sex and learning (the time, love and memory of the title) were the slaves of particular genes.
Benzer then looked to see if behaviour-associated gene products traced to drosophila brains could also be found in humans. They could. Human and fly brains are, to a degree, composed of the same stuff. Studies in humans have shown that individual genes may influence particular behavioural traits. A genetic basis has been proposed for aggression, homosexuality, intelligence, creativity, appetite, alcoholism, depression and many other "human" characteristics. However, even the greatest proponents of genetic determinism in humans accept that nature and nurture work together in shaping how we think and act. Blake himself (in the same poem dissected by Weiner for his epigraph) concluded that flies don't think: he was concerned with the tortuousness of the human brain, whose reasonings confound the simplicity of life. Blake despaired at Newton's dismantling of life and the advent of scientific reductionism.
At his most pessimistic, Weiner refers us to A Clockwork Orange, uneasy that some Machiavellian instinct to control human behaviour might push the application of Benzer's discoveries towards what Churchill saw as "the perverted evils of science". Weiner, however, is adamant that scientists should not be vilified for the outcomes of their innocent curiosity. Einstein was not thinking of Hiroshima when he spotted that e equalled mc2. It needed a Churchill for that.
Michael Barrett is a lecturer at the Institute of Biomedical and Life Sciences, University of Glasgow