By Bhavana Weidmann | January 25, 2013
Excerpt: “Adolescent rats exposed to stress grow into pathologically aggressive adults, behaviors that may be explained by accompanying epigenetic changes and altered brain activity.”
My comment: A recent report of diet-driven changes in the genome of dogs compared to wolves and a recent report of behavioral differences driven only by chemosensory input during exploration in 3-4 week-old wolves, but by multisensory input in 4 week-old dogs, attest to the importance of the epigenetic effects of nutrient stressors combined with social stressors on the development of the brain and behavior. It is also becoming clearer how nutrient-dependent stress and social stress epigenetically contribute to the microRNA / messenger RNA balance, intracellular signaling, and stochastic gene expression in the amygdala, which apparently is how learning and memory is epigenetically effected by food odors and pheromones in mammals.
As the molecular mechanisms of cause and effect become clear, is there any reason to suspect that adaptive evolution of the brain and behavior in mammals (e.g., dogs and wolves) is less dependent on nutrients and pheromones than the hormone-organized and hormone-activated brain development and behavior of invertebrates? If not, then “Olfaction and odor receptors provide a clear evolutionary trail that can be followed from unicellular organisms to insects to humans.” If so, social programs might at least begin to consider the role of human pheromones (or their absence) as social stressors that alter adolescent and adult behavior in precisely the same way they alter the behavioral differences of all species (as exemplified in subspecies like in the wolves and dogs). If the epigenetic effects are on the molecular mechanisms of adaptively evolved brain development in other species, how can we eliminate human pheromones from consideration in social programs designed to help our stressed-out conspecifics?