Among biology’s more riveting inquiries is the investigation of gene-environment interactions — the demonstration that a person’s genes constantly react to experience in a way that changes behavior, which in turn shapes environment, which in turn alters gene expression and so on. As David Olds described a few weeks ago, this new subdiscipline is yielding startling insights about how nature and nurture mix to help determine one’s health and character.

Gene-Environment Interactions: When Nurture Wears a White Hat

The importance and challenge of the nature-nurture debate in behavior has recently spawned a new area of research that looks at the interaction between genetic risk factors and experience in the development of psychopathology. A study led by Joan Kaufman and Joel Gelernter, both of Yale, and published in Biological Psychiatry, has demonstrated what many of us have intuitively concluded, which is that both nature and nurture contribute to who we are. In this particular study, genetic and environmental factors interact to determine risk for depression…

As with any behavioral genetic study, one must be careful not to overinterpret these findings, because virtually no study in behavioral genetics is consistently or completely replicated. Nonetheless, some additional points about this paper can help inform us on the nature-nurture debate. First, depression scores and categorical diagnoses of depression were significantly higher in children with a history of maltreatment versus controls even before any genetic analysis was factored in. In a similar vein, the highest average depression score of any genotype category in the unabused control children was lower than the average depression score for any genotype category in the maltreated children; genes alone weren’t likely to make the child depressed, but maltreatment alone could.

These findings suggest that, at least regarding these specific polymorphisms, nurture beats nature. This conclusion will come as a relief to believers in human free will. It also argues strongly for the identification of children at risk for maltreatment and strong actions to reverse the negative effects of this experience.

Source: Scientific American
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