Children who have been abused or neglected early in life are at risk for developing both emotional and physical health problems. In a new study, scientists have found that maltreatment affects the way genes are activated, which has implications for children’s long-term development. Previous studies focused on how a particular child’s individual characteristics and genetics interacted with that child’s experiences in an effort to understand how health problems emerge. In the new study, researchers were able to measure the degree to which genes were turned “on” or “off” through a biochemical process called methylation. This new technique reveals the ways that nurture changes nature — that is, how our social experiences can change the underlying biology of our genes.
The researchers found an association between the kind of parenting children had and a particular gene (called the glucocorticoid receptor gene) that’s responsible for crucial aspects of social functioning and health. Not all genes are active at all times. DNA methylation is one of several biochemical mechanisms that cells use to control whether genes are turned on or off. The researchers examined DNA methylation in the blood of 56 children ages 11 to 14. Half of the children had been physically abused.
They found that compared to the children who hadn’t been maltreated, the maltreated children had increased methylation on several sites of the glucocorticoid receptor gene, also known as NR3C1, echoing the findings of earlier studies of rodents. In this study, the effect occurred on the section of the gene that’s critical for nerve growth factor, which is an important part of healthy brain development.
There were no differences in the genes that the children were born with, the study found; instead, the differences were seen in the extent to which the genes had been turned on or off. “This link between early life stress and changes in genes may uncover how early childhood experiences get under the skin and confer lifelong risk,” notes Seth D. Pollak, professor of psychology and pediatrics at the University of Wisconsin, Madison, who directed the study. More.
Or, as one expert put it, “If you think love conquers all, you’re not paying attention.”
If this finding holds up, it may provide two valuable tools:
It may shed some light on why children who were mistreated early in life can be difficult to rehabilitate. Many (not all, of course) continue to behave as if they were living in a high threat, low attachment environment—when they have in fact been living for years in a low threat, high attachment environment. That is, some children don’t seem to adjust to their actual circumstances over time, as one might expect. Something is wrong, but what? “Born bad” just doesn’t cut it by way of an explanation any more. We want more specifics.
Second, a clearer idea of what is going on would enable us to develop better strategies for rehabilitation. Which is the main reason for studying the problem anyway.
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