Below, we review the existing

literature linking specific genes with individual’s rank or the characteristics of the social hierarchy. We would also like to express a word of caution. The failure to replicate findings from previous candidate gene association studies is common and a major concern. Ideally, future studies should adhere to the recommendations as expressed by Buxbaum and others including the use of appropriately large sample sizes, standardized and careful data cleaning and corrections for multiple testing 19 and 20]. Unbiased genome-wide screens as exemplified by van der Loos and colleagues represent Selleckchem Crizotinib a step in the right direction [21]. The monoaminergic systems have received considerable attention in

the context of social hierarchies probably due to their known roles in other related traits, such as aggression, emotionality, motivation and reward. A few studies have examined the potential role of the serotonin transporter (SLC6A4) in social dominance. Male SLC6A4 knockout (KO) mice, while able to form a social hierarchy, are submissive in dyadic encounters with wildtype mice [22]. However, the interpretation of these results should take into account that these mice also display increased anxiety and reduced locomotion 23 and 24]. In rhesus monkeys and humans, the SERT presents genetic variation, BKM120 in vitro including functional short and a long allele versions, which are associated to differences in emotion regulation and increased anxiety in short allele-carriers [26]. Whereas in female cynomolgus macaques, no individual SLC6A4 variants or haplotypes were significantly associated with social rank [27], female rhesus monkeys carrying the SLC6A4 short allele were found to be most often involved in agonistic behavior regardless of social rank [28]. These findings suggest that SLC6A4 might influence social hierarchies by acting through other aspects of social behavior instead of directly affecting social rank. This is in line with human data indicating Interleukin-2 receptor that differences in the frequency

of the SLC6A4 allele variants in specific populations is associated with differences in social hierarchy beliefs (i.e. cultural values of individualism and collectivism) 28 and 29]. Nations that are more hierarchically organized (as indicated by greater power distance) were found to be composed of more individuals carrying at least one short allele of the SLC6A4 gene [28]. Recently, a gene-environment interaction model has been proposed to more accurately explain cross-national differences in social hierarchy values and beliefs. Data from 28 societies supported an interaction between population frequency of the SLC6A4 gene and presence of threats on the prediction of population level of acceptance of social hierarchies and central authority [30].