An active area of our research focuses on the genetic mechanisms by which organisms evolve exceptional body sizes. We use house mice from Gough Island – the largest wild house mice on record – as our model system. The work integrates genetic mapping of quantitative trait loci for body weight throughout the growth trajectory, transcriptomics of metabolic organs, phenotypic characterization of congenic strains, and population genomics. Our comprehensive phenotyping also includes measures of interest to diabetes and obesity, which we use to help elucidate novel genetic mechanisms of metabolic disease development and progression.