UCLA

Genetic factors are likely involved in many aspects of human social behavior, yet influences of molecular genetic markers on aspects of human intimate relationships have only recently been documented. The present dissertation begins with a review of these recent advances which have collectively given rise to the transdisciplinary sub-field of relationship genetics (Chapter Two). Particular attention is given to candidate gene studies of intimate relationship characteristics and to the elusive but tantalizing notion of "genetic compatibility" between intimate relationship partners. The review is followed by two original studies. The first of these (Chapter Three) investigates the effects of matching at major histocompatibility complex (MHC) gene markers between existing long-term relationship partners on self-reported levels of in-pair attraction. The results provide qualified support for the hypothesis that higher levels of matching between relationship partners at MHC markers leads to reduced levels of attraction between those partners. However, this effect appears to be strong and reliable only for individuals of Asian ancestry, whereas the evidence for such an effect in individuals of non-Asian ancestry is far more equivocal. The second study (Chapter Four) applies a genetic technique known as haplotype analysis to investigate associations between variation in the oxytocin receptor gene (OXTR) and self-report measures of individual differences and relationship parameters collected from partners in long-term intimate relationships. Few effects were found for measures of relationship quality, but a number of interesting and consistent associations were uncovered between OXTR haplotypes and measures of extra-pair interest and desire. Taken as a whole, the present work documents the emergence of an exciting new subfield and presents two novel contributions to this nascent literature. Relationship genetics offers the prospect of marrying cutting edge molecular genetic techniques to the investigation of questions that have been at the center of human life and thought since time immemorial.