The Human Genome Project reached its official completion this year, exactly half a century after James Watson and Francis Crick announced their discovery of the structure of DNA. The coincidence has inspired a number of commemorations and has focused attention on the role of genetics in society.
One example is a conference hosted by the American Association for the Advancement of Science (AAAS) in May, titled, "Can We Talk? A Public Meeting on Behavioral Genetics and Society." The meeting brought together researchers, policy experts and members of the public to discuss the implications of research on genetics and behavior.
Such research could influence public policy on education, crime, mental health and many other issues, said Alan Leshner, PhD, CEO of AAAS. Because of its potential impact, he added, "People must understand not only the complexity of behavioral genetics, but all its implications."
The implications for mental illness are especially clear. The Human Genome Project may help researchers identify risk factors for such illnesses, said Steven Hyman, MD, provost of Harvard University and former head of the National Institute of Mental Health. But, he cautioned, much work remains to be done. "My nightmare is that we will find hundreds of genes, each contributing only 1 percent or 1.5 percent," he said.
Hyman's "nightmare"--the possibility that research will reveal many small risk factors, but no large ones--was debated by psychologists at the conference.
While Hyman thought the scenario unlikely, University of Virginia psychologist Eric Turkheimer, PhD, took a gloomier view. He predicted that the more geneticists learn about the biology of heritability, the messier their science will become--and the more genetics will start to resemble psychology.
"Genetics is going to begin dealing with the exact same complexities that behavioral scientists have been looking at for the past 100 years," said Turkheimer.
Psychologists Matt McGue, PhD, and Irving Gottesman, PhD, both of the University of Minnesota, were more sanguine about the possibility of finding genes that significantly increase the risk of serious mental illnesses. For illnesses such as schizophrenia and bipolar disorder, the evidence for genetic influences is particularly strong, said Gottesman. In the 1960s, his research on schizophrenia set the standard for twin studies of psychopathology.
Given the field's checkered past, its findings have to be interpreted carefully, the speakers agreed. In the early 20th century, behavioral genetics was used to justify eugenic policies in Nazi Germany and elsewhere.
When properly used, however, behavioral genetics can help psychologists chart a middle course between genetic and environmental explanations, says McGue.
"The future for me as a psychologist, and I think for most behavioral geneticists, is how the two come together," said McGue, who directs the University of Minnesota's graduate psychology program in behavioral genetics.