The genetic basis of behavior: burrow construction in wild mice


February 11, 2015 - 1:00pm
NW 243
About the Speaker
Hillery Metz (Hoekstra Lab)

The genetic underpinnings of ecologically-important behavioral variation remain poorly understood, yet this information could transform our understanding of behavioral evolution. Here, we focus on burrow construction in two sister-species, the deer mouse (Peromyscus maniculatus) and the oldfield mouse (P. polionotus). Like other mice in the genus, the deer mouse constructs a simple burrow with a single, short tunnel leading to a nest chamber. By contrast, in the oldfield mouse, burrow construction is complex such that burrows are long and composed of multiple tunnels, including an “escape tunnel.” We investigated the genetic basis of this complex behavior across four advanced backcross generations (BC2-BC5) to hone in on the genomic regions underlying this dramatic difference in burrow architecture. Using genome-wide ddRAD markers to genotype >600 individuals followed by a QTL analysis, we identified multiple loci associated with differences in burrow structure. Although preliminary, fine-scale mapping for the tunnel length phenotype points to a promising candidate gene implicated in addiction behavior in lab mice, the muscarinic acetylcholine receptor Chrm5. In the brain, this gene is expressed in dopaminergic neurons and is differentially expressed in the whole brain extracts of P. maniculatus and P. polionotus. This work points to a possible neural mechanism underlying the evolution of a natural mammalian behavior.