Meeting Abstract
The house mouse, Mus musculus domesticus, colonized the Americas in conjunction with early European settlers 200-400 years ago. Since their arrival, house mice have rapidly expanded their range and now occur in a variety of novel and extreme habitats from Alaska to Tierra del Fuego making them an excellent system for identifying loci that underlie rapid environmental adaptation. We have collected tissue, phenotypic data, and live mice from latitudinal transects across North and South America that vary dramatically in temperature, precipitation, and seasonality. We find phenotypic clines in several adaptive traits including body size and coat color. In order to examine genetically based phenotypic differences in behavioral and physiological differences involved in environmental adaptation, we collected live mice from populations at the extremes of these transects and bred them in a common laboratory environment for five generations. Among other interesting differences, we find that cold adapted mice from New York & Canada build bigger nests and are more active than Tucson, Florida, & Brazil mice. To identify the genetic basis of environmental adaptation in house mice we use both population genomic and quantitative trait locus (QTL) mapping approaches. We find that exciting candidate genes involved in processes such as osmoregulation, energy metabolism, and circadian rhythms are under selection. Therefore we conclude that despite their recent introduction to the Americas, house mice have undergone rapid genetic diversification and adaptation to novel climates.
