Genetics and genomics of social behaviour in a chicken model

The identification of genes affecting behaviour can be problematic, yet their identification allows a raft of possibilities. Sociality and social behaviour can have multiple definitions, though at its core it is the desire to seek contact with con- or hetero-specifics. The identification of genes affecting sociality can therefore give insights into the maintenance and establishment of sociality. In this study we used the combination of an advanced intercross between wild and domestic chickens with a combined QTL and eQTL genetical genomics approach to identify genes for social reinstatement (SR) behaviour. A total of 24 SR QTL were identified and overlaid with over 600 eQTL obtained from the same birds using hypothalamus tissue. Correlations between overlapping QTL and eQTL indicated 5 strong candidate genes, with the gene TTRAP being strongly significantly correlated with multiple aspects of SR behaviour, as well as possessing a highly significant eQTL. The distribution of eQTL can also indicate the genetic mechanisms underlying domestication itself. Multiple eQTL were found to in discrete clusters, however tests for pleiotropy show that these blocks were primarily linked in origin. This suggests that clustered genetic modules, rather than pure pleiotropy (as hypothesised by the neural crest theory) appears to be driving domestication in the chicken.