Gut microbiome community structure correlates with different behavioral phenotypes in the Belyaev Farm-Fox Experiment.

Domestication represents one of the largest biological shifts of life on Earth, and for many animal species, behavioral selection is thought to facilitate early stages of the process. The gut microbiome of animals can respond to environmental changes and have diverse and powerful effects on host behavior. As such, we hypothesize that selection for tame behavior during early domestication, may have indirectly selected on certain gut microbiota that contribute to the behavioral plasticity necessary to adapt to the new social environment. Here, we explore the gut microbiome of foxes from the tame and aggressive strains of the "Russian-Farm-Fox-Experiment". Microbiota profiles reveal a significant depletion of bacteria in the tame fox population that have been associated with aggressive and fear-related behaviors in other mammals. Our metagenomic survey allows for the reconstruction of microbial pathways enriched in the gut of tame foxes, such as glutamate degradation, which converge with host genetic and physiological signals, revealing a potential role of functional host-microbiota interactions that could influence behaviors associated with domestication. Overall, by characterizing how compositional and functional potential of the gut microbiota and host behaviors co-vary during early animal domestication, we provide further insight into our mechanistic understanding of this adaptive, eco-evolutionary process.