UC Berkeley

The human commensal, Mus musculus domesticus, is native to the Eurasian continent, having spread from north of the Indo-Pakistani subcontinent and the Middle East to western Europe by the end of the Iron Age. Wild populations of M. m. domesticus are now distributed across Africa, the Americas, and Oceania, a range consistent with the global migration of western Europeans that began in the late 15th century. Despite its standing as the premier mammalian model organism for biomedical, ecological, and evolutionary research, important details surrounding the population history of wild house mice remain a mystery. To investigate patterns of genetic structure and infer the demographic history of the western house mouse, I analyze collections of genomic and exomic sequences generated from mice sampled in western Europe and the Americas. First, I present evidence that connects the colonization history of house mice in eastern North America to the colonization history of the Americas by European settlers which began in the late 15th century. Then, I analyzed a genomic dataset from an expanded sampling of Western Europe, including 59 new whole genome sequences from historically relevant regions of Western Europe, and present evidence of population structure, population splits, and gene flow between distinct populations of Western European house mice. Lastly, I combine datasets comprised of Western European genomes and North and South American exomes to detail the recent colonization history of house mice in both American continents. Altogether, these results elucidate details around the recent introduction of Western European house mice to North and South America, highlighting the effects of human migration and global colonization on the concurrent spread of an invasive human commensal.