A rodent mother can't scold or praise her offspring, but her approach to mothering lays a genetic foundation for her pups' life-long response to threats, neuroscientists have found.
Rats raised by moms who frequently lick and groom them undergo permanent changes in patterns of gene activity, leading to a penchant for exploratory behavior in stressful situations, say Michael J. Meaney and his colleagues at McGill University in Montreal.
In contrast, rats raised with little maternal contact end up with gene activity that fosters fearfulness in the face of stress, the researchers report in the August Nature Neuroscience. From an evolutionary perspective, having both behaviors in a population is beneficial.
"Early experience can have lifelong consequences on behavior, and [this new report] reveals the genetic scaffolding of this phenomenon to an unprecedented extent," remarks neuroscientist Robert Sapolsky of Stanford University.
Meaney's group previous