The extent and quality of parental care that children receive greatly influences their development, impacting their physical and psychological growth, their educational and social achievement, and their disease risk as both children and adults. It is thus remarkable that around 25% of children are physically abused worldwide. Parenting is a complex behavior, and we still know little about the causes and mechanisms by which people differ in their parental behaviors. To learn more about the mechanistic basis of parental care, I took an evolutionary-comparative approach. I set out to identify the genetic, molecular, and neuronal bases of the evolution of parental care in a pair of closely-related sister species of deer mice (genus Peromyscus) that have naturally evolved dramatically-different parental behaviors. Using quantitative-genetics techniques, I localized 13 genetic regions that contribute to interspecific differences in parental behavior. Remarkably, most of these regions differentially affect maternal and paternal behavior, implying that parental behavior evolves through different genetic routes in the two sexes. In one of these regions, I narrowed in on a specific gene, the neuropeptide vasopressin, and showed that it mediates interspecific differences in parental nest-building behavior. This gene is expressed at 3-fold higher levels in the hypothalamus of the less parental Peromyscus species. Finally, I confirmed the causal role of this neuropeptide by demonstrating that an increase in vasopressin levels in the brains of the more parental Peromyscus species inhibits their parental care. Together, an evolutionary-genetics approach led to the discovery that variation in parental behavior has a different genetic basis in males and females and to finding that the highly-conserved neuropeptide vasopressin modulates parental behavior.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology