Both maternal care received and genotype influence stress-related phenotype in female rats.

Rat dams differ naturally in the level of maternal care they provide to their offspring within the same litter. We explored possible mechanisms of differential maternal care focused on genetic variation. We examined single nucleotide polymorphisms in the glucocorticoid receptor, FK506-binding protein, and serotonin transporter genes in two separate cohorts, and the relationship between differential maternal care received, genotype, and offspring phenotype. Allelic variation in all three genes was significantly associated with levels of maternal care received by offspring and behavioral and endocrine stress responses in adulthood. Differences in pup behavior were also associated with allelic variation in these genes. Together, these results indicate that the dam/pup interaction is dynamic and implicate the genotype of the offspring in influencing the level of maternal care received. They further suggest that some genotypes may have a dampening effect on the impact of maternal care on stress-related phenotypes in adulthood.