Figure 1. Distribution of populations and subspecies sampled.

M. m. domesticus occurs in Western Europe, M. m. musculus in Eastern Europe and Asia. The dashed red line marks the contact region where a classical hybrid zone has formed. Samples come from France (Fra – region Massif Central), Germany (Ger – region Cologne/Bonn), Czech Republic (Cze – region Studenec) and Kazhakstan (Kaz – region Almaty, note that this is not on the map anymore, as indicated by the arrow). The inset depicts the phylogenetic relationship between the populations, as well as an indication of the parameters used for population modeling. Map picture based on a map from http://d-maps.com.