The role of oxytocinergic genes in the intergenerational transmission of parent-child relationship qualities

Joint Roles of Oxytocin- and Dopamine-Related Genes and Childhood Parenting Experience in Maternal Supportive Social Network

How genes and parenting determine maternal social support availability, an important preventive factor of postpartum depression, has been little studied. Our study aimed to examine the interaction effects of maternal sociality-related gene and parenting on maternal social support. We analyzed data of 115 triads of Japanese grandmothers, mothers, and their infants. An interaction between parenting and cumulative genetic risk, calculated on the sociality-related genes (OXTR rs53576, rs2254298, rs1042778; COMT rs4680), was found. Mothers with high genetic risk received less social support if received poorer parenting (B = - 0.02, 95%CI = - 0.04 to - 0.01), while no association among low-risk mothers. Poorer social support was associated with severer depression in high-risk mothers (B = - 0.88, 95%CI = - 1.45 to -0.30). Our results suggest that mothers carrying risk alleles of sociality-related genes are particularly sensitive to childhood parenting, underscoring the importance of childhood parenting and genetic risk to understand maternal help-seeking behavior.

The Pan social brain: An evolutionary history of neurochemical receptor genes and their potential impact on sociocognitive differences

Humans have unique cognitive capacities that, compared with apes, are not only simply expressed as a higher level of general intelligence, but also as a quantitative difference in sociocognitive skills. Humans' closest living relatives, bonobos (Pan paniscus), and chimpanzees (Pan troglodytes), show key between-species differences in social cognition despite their close phylogenetic relatedness, with bonobos arguably showing greater similarities to humans. To better understand the evolution of these traits, we investigate the neurochemical mechanisms underlying sociocognitive skills by focusing on variation in genes encoding proteins with well-documented roles in mammalian social cognition: the receptors for vasopressin (AVPR1A), oxytocin (OXTR), serotonin (HTR1A), and dopamine (DRD2). Although these genes have been well studied in humans, little is known about variation in these genes that may underlie differences in social behavior and cognition in apes. We comparatively analyzed sequence data for 33 bonobos and 57 chimpanzees, together with orthologous sequence data for other apes. In all four genes, we describe genetic variants that alter the amino acid sequence of the respective receptors, raising the possibility that ligand binding or signal transduction may be impacted. Overall, bonobos show 57% more fixed substitutions than chimpanzees compared with the ancestral Pan lineage. Chimpanzees, show 31% more polymorphic coding variation, in line with their larger historical effective population size estimates and current wider distribution. An extensive literature review comparing allelic changes in Pan with known human behavioral variants revealed evidence of homologous evolution in bonobos and humans (OXTR rs4686301(T) and rs237897(A)), while humans and chimpanzees shared OXTR rs2228485(A), DRD2 rs6277(A), and DRD2 rs11214613(A) to the exclusion of bonobos. Our results offer the first in-depth comparison of neurochemical receptor gene variation in Pan and put forward new variants for future behavior-genotype association studies in apes, which can increase our understanding of the evolution of social cognition in modern humans.

How stress can influence brain adaptations to motherhood

Research shows that a woman's brain and body undergo drastic changes to support her transition to parenthood during the perinatal period. The presence of this plasticity suggests that mothers' brains may be changed by their experiences. Exposure to severe stress may disrupt adaptive changes in the maternal brain and further impact the neural circuits of stress regulation and maternal motivation. Emerging literature of human mothers provides evidence that stressful experience, whether from the past or present environment, is associated with altered responses to infant cues in brain circuits that support maternal motivation, emotion regulation, and empathy. Interventions that reduce stress levels in mothers may reverse the negative impact of stress exposure on the maternal brain. Finally, outstanding questions regarding the timing, chronicity, types, and severity of stress exposure, as well as study design to identify the causal impact of stress, and the role of race/ethnicity are discussed.