The genetic basis of burrowing behaviour in Peromyscus mice


October 16, 2019 - 12:00pm
Northwest Building 243
About the Speaker
Nicole Bedford
Speaker Title: 
Postdoctoral Researcher
Speaker Affiliation: 
Hoekstra Lab

Understanding the genetic basis of behavioral diversity remains a major challenge in evolutionary biology. Here, we capitalize on extreme variation in innate burrowing between two sister-species of deer mice (genus Peromyscus) to investigate the behavioral mechanisms and genetic architecture underlying evolved differences in behavior. The ancestral burrow form, exemplified by P. maniculatus, is short and simple. By contrast, the evolutionarily-derived burrow form of P. polionotus is long and complex. However, we still do not know the precise changes in behavior that give rise to overall differences in species-specific burrow architecture. Here, we use a novel behavioral assay—coupled with automated video analysis and detailed photo quantification—to uncover the behavioral mechanisms underlying variation in burrow architecture. Despite no difference in overall activity, we document that P. polionotus spends more of its active time underground. We also find that P. polionotus achieves a longer burrow by digging for twice as long, and by digging 5 times more efficiently, than P. maniculatus. Furthermore, we show that these component traits map to different parts of the genome. Together, these findings demonstrate that complex behavior can be broken down into its constituent parts to reveal distinct genetic underpinnings for separate components. This provides a useful framework for understanding the role of candidate genes in shaping different behavior components: natural selection may target genes expressed in different circuits, each contributing to distinct components of burrowing behavior, such as timing or efficiency of digging. Careful quantification of the precise behavioral changes that lead to overall differences in burrow architecture is therefore critical, both for the identification and interpretation of candidate genes.