“Lifelong Effects of Good Parenting: How Experience affects Gene Expression” by Michael Meaney
“Good” rat moms (those who more frequently lick and groom their pups) produce offspring who, throughout their lives, explore more, are less fearful & less reactive to stress, perform better cognitively, and preserve their cognitive skills better into old age. It is the mother’s behavior that produces these effects rather than genes: Pups of ‘good’ moms raised by low-licking-and-grooming moms do not show these characteristics, and pups of low-touch moms raised by high-touch moms do show this constellation. Here’s an example of early experience (nurturing touch, or its absence) producing enduring, life-long effects.
Rats tend to raise their offspring the way they were raised, so these effects are transmitted intergenerationally, not through the genes but through behavior: The biological offspring of low-touch moms, cross-fostered to high-touch moms, lick and groom their offspring a lot, and thus the diminished stress reactivity and cognitive enhancement is passed down through the generations.
Maternal behavior produces these behavioral consequences through altering gene expression. Not all genes in an individual are expressed. Many are never expressed. Experience affects which genes are turned on and off, in which cells, and when. For example, lots of touch by rat moms turns on (for life) the glucocorticoid receptor gene in offspring, hence lower circulating glucocorticoid levels, so they feel less stressed.
(a) To understand how experience can affect gene expression (epigenesis).
(b) To understand the profound effect parenting can have on cognitive and emotional functioning throughout life and through succeeding generations.
(c) To understand that most of our genes are not expressed and to understand something about the mechanisms that turn genes off and on.
This talk was given at the conference “Brain Development and Learning 2010 Meeting” in Vancouver. It was an interdisciplinary conference devoted to improving children’s lives by making cutting-edge research in neuroscience, child psychology, & medicine. Further information available on http://www.interprofessional.ubc.ca/bdl.html