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Researchers Consider Role of Genetics, Environment
at Root of Complex Behaviors
Researchers speaking at a AAAS meeting on behavioral genetics yesterday warned against allowing fear to block scientific progress in a field once associated with efforts to weed out undesirable traits from the human gene pool.
"Science should not be inhibited, even if we are afraid of what we will find," said Steven E. Hyman, former director of the National Institute of Mental Health and provost at Harvard University. "We can't turn away from science, but we do have to manage the consequences."
Hyman spoke on the morning of 2 May, opening the two-day meeting entitled, "Can We Talk? A Public Conversation About Behavioral Genetics and Society." Hyman and three other behavioral scientists addressed how far science has come in determining the role of genetics in illnesses such as schizophrenia and bipolar disorders, and in other complex human behaviors. The program continued Friday afternoon and all-day Saturday, with discussions regarding behavioral genetics, ethics and policy conducted by leading scientists, ethicists, journalists, legal scholars and patient advocates.
"It is very important to get a sophisticated understanding of the role of genetics in the control of behaviors," said Alan I. Leshner, CEO of AAAS. "It is also very important that AAAS is having this meeting because people must understand not only the complexity of behavioral genetics, but all its implications. With this meeting, we initiate the dialogue."
Progress in behavioral genetics, and the improved treatments it promises, must be urgently sought, Hyman said, in light of the economic, social and emotional toll of disorders such as depression, schizophrenia, and autism.
"Mental disorders are responsible for too high a share of the disease burden worldwide," Hyman said, adding that depression is the leading cause of disability in the United States.
According to Hyman and the researchers who joined him to talk about advances in behavioral genetics, there are several barriers that researchers face in pinpointing genetic causes of behavioral disorders. He noted the challenge of identifying phenotypes, as well as the large number of environmental and genetic factors at play, and the difficulty of understanding how they interact with each other.
"Genes have a lot to say, but they are not causal," Hyman said. "In the end, it is our brains that control our behavior. In bringing knowledge together, it is critical that we not leave the brain out of the equation."
University of Minnesota psychologist Matt McGue spoke of the time 40 years ago, when "nurture" held sway over "nature," and mental illness was thought to come out of unhealthy relationships beween parents and children. To explain a possible interplay between genetic and environmental factors, McGue described the case of an adopted child with anti-social behavior who had been harshly disciplined by his adopted father.
"We create our enviroments by the choices we make and by the reactions our behaviors evoke in others," McGue said. "The offspring's behaviors are a result of heredity, but that misbehavior evokes harsh parenting, and that harshness feeds back into the misbehavior."
Eric Turkheimer, professor of psychology at the University of Virginia, noted that most human behaviors appear to be somewhat heritable, and all traits seem to be due to a combination of genetic and environmental factors. Science, he said, may never know which factors play the greatest role.
"You can't study traits in parents and their kids because you don't know what's environmental and what's genetic," Turkheimer said, adding that obligations to human subjects would not permit studies that could provide those answers.
The behavioral genetics meeting continued Saturday, with a discussion of "Genes, Environment and Alcoholism," by David Goldman, chief of the laboratory of neurogenetics at the National Institute on Alcohol Abuse and Alcoholism, and continuing with a panel on engaging the public in discussions on behavioral genetics.
2 May 2003
More details on this conference are online at www.aaas.org/spp/bgenes/cwt.