Existence of a major control locus for basic behavioral traits

Animals show behavioral traits that can collectively be called personality and can be measured by standardized tests. We have studied the Prader-Willi Syndrome (PWS) gene region which includes two clusters of tandem repeats coding for small nucleolar RNAs, SNORD115 and SNORD116. SNORD115 is known to regulate splicing of the serotonin receptor Ht2cr and SNORD116 is predicted to interact with the transcript of the chromatin regulator Ankrd11. In this study we showed that both snoRNA clusters display major copy number variation within and between populations and that this affects the expression of more than 130 genes which are themselves known to be involved in a variety of pathways including serotonin regulation, metabolism, cognitive ability, vocalization and craniofacial feature development. Using a set of behavioral scores related to personality in populations of two species of wild mice, guinea pigs and humans, we find a strong correlation between the snoRNA copy number and these scores. These results also suggested the co evolution of personality and other traits such as metabolism, cognitive ability, vocalization and craniofacial feature. As conclusion, this study suggests that the SNORD clusters in the PWS region are major regulators of personality and correlated traits. This finding is very unexpected, since it suggests the existence of a major control locus for basic behavioral traits, with an inbuilt mechanism to ensure variance in behavioral strategies within a population