Gene–culture interaction: influence of culture and oxytocin receptor gene (OXTR) polymorphism on loneliness

Mendelian randomization (MR) permits causal inference between exposures and a disease. It can be compared with randomized controlled trials. Whereas in a randomized controlled trial the randomization occurs at entry into the trial, in MR the randomization occurs during gamete formation and conception. Several factors, including time since conception and sampling variation, are relevant to the interpretation of an MR test. Particularly important is consideration of the “missingness” of genotypes that can be originated by chance, genotyping errors, or clinical ascertainment. Testing for Hardy-Weinberg equilibrium (HWE) is a genetic approach that permits evaluation of missingness. In this paper, the authors demonstrate evidence of nonconformity with HWE in real data. They also perform simulations to characterize the sensitivity of HWE tests to missingness. Unresolved missingness could lead to a false rejection of causality in an MR investigation of trait-disease association. These results indicate that large-scale studies, very high quality genotyping data, and detailed knowledge of the life-course genetics of the alleles/genotypes studied will largely mitigate this risk. The authors also present a Web program (http://www.oege.org/software/hwe-mr-calc.shtml) for estimating possible missingness and an approach to evaluating missingness under different genetic models.

This study used an attachment theoretical framework to investigate support-seeking and caregiving processes in intimate relationships. Dating couples (N = 93) were videotaped while one member of the couple (support seeker) disclosed a personal problem to his or her partner (caregiver). Results indicated that when support seekers rated their problem as more stressful, they engaged in more direct support-seeking behavior, which led their partners to respond with more helpful forms of caregiving. Responsive caregiving then led seekers to feel cared for and to experience improved mood. Evidence for individual differences was also obtained: Avoidant attachment predicted ineffective support seeking, and anxious attachment predicted poor caregiving. Finally, couples in better functioning relationships engaged in more supportive interactions, and participants' perceptions of their interaction were biased by relationship quality and attachment style.