Affiliation: Biology Department, Monmouth University, West Long Branch, NJ
Keywords: Natural selection
Body size in house mice (Mus musculus domesticus) covaries with latitude, consistent with Bergmann’s Rule. There is clear evidence that genetic variation contributes to this pattern in the Americas. However, traits related to body size are complex not only because they are polygenic, but alsobecause they are sensitive to the environment and, in particular, diet. In nature, mice are subject to variation in food availability/quality and latitude is expected to affect seasonality of food resources. New wild-derived strains from regions of the Americas have been developed which vary consistently in aspects of body size in a common laboratory environment, presenting an opportunity to investigate plasticity in response to diet. In this study, male and female mice were fed either a typical breeder diet or a high fat diet after weaning. Body weight, aspects of size, and food intake were measured regularly over twelve weeks. Results suggest not only that diet affected body size, but also that strains differed in response to the high fat diet. Future research will include analysis of differential expression among strains on both diets to help connect regulatory variants to differences in body size.