ReviewGenes, hormones, and circuits: An integrative approach to study the evolution of social behavior

Tremendous progress has been made in our understanding of the ultimate and proximate mechanisms underlying social behavior, yet an integrative evolutionary analysis of its underpinnings has been difficult. In this review, we propose that modern genomic approaches can facilitate such studies by integrating four approaches to brain and behavior studies: (1) animals face many challenges and opportunities that are ecologically and socially equivalent across species; (2) they respond with species-specific, yet quantifiable and comparable approach and avoidance behaviors; (3) these behaviors in turn are regulated by gene modules and neurochemical codes; and (4) these behaviors are governed by brain circuits such as the mesolimbic reward system and the social behavior network. For each approach, we discuss genomic and other studies that have shed light on various aspects of social behavior and its underpinnings and suggest promising avenues for future research into the evolution of neuroethological systems.

Graphical abstractAn integrative framework for studying the evolution of social behavior at the individual and population level. We propose that modern genomic approaches can facilitate such studies by integrating four approaches: (1) animals face many challenges and opportunities that are ecologically or socially equivalent across species; (2) they respond with species-specific, yet quantifiable and comparable approach and avoidance behaviors; (3) these behaviors in turn are regulated by gene modules and neurochemical codes; and (4) these behaviors are governed by brain circuits such as the mesolimbic reward system and the social behavior network.Download full-size imageResearch highlights► Animals face challenges and opportunities that are equivalent across species. ► Animals respond with quantifiable species-specific approach and avoidance behaviors. ► Approach/avoidance behaviors are regulated by gene modules and neurochemical codes. ► The mesolimbic reward system and the social behavior network regulate behavior. ► Phenologs and developmental system drift can illuminate the evolution of behavior.