Our first set of analyses revealed a significant association between the rs7632287 SNP and self reported partner-bonding behavior within the TOSS sample, as assessed by the Partner Bonding Scale (PBS) (49). For the younger women in the TCHAD sample, the same SNP was significantly associated with the affection subscale of the Relationship Quality Survey (RQS) (62) (Table 2). The P-values from both studies were combined using Fisher’s method (63), taking effect direction into account by regarding the TCHAD sample as a replication sample and performing a one-tailed test for the association between rs7632287 and the RQS scale. This resulted in a combined P-value of 0.004, significant (P<0.05) after Bonferroni correction for the twelve tests performed. We found no significant associations between any other OXTR SNPs and PBS or RQS scores in women and in line with our hypothesis based on animal data no consistent association was found in men. Consequently, all subsequent analyses focused upon women.
