Phylogeography of wild and laboratory house mice included in a study of the Inner ear morphology
D-loop sequences were obtained from wild and laboratory mice included in a study of the inner ear morphology to characterise and compare their haplotype composition. Four groups of mice were compared here: (1) several populations of wild mice trapped in commensal habitats in France; (2) their second-generation laboratory offspring, to assess plastic effects related to breeding conditions; (3) a standard laboratory strain (Swiss); (4) hybrids between wild offspring and Swiss mice. The morphology of the semi-circular canals was quantified using a set of 3D landmarks and semi-landmarks analyzed using geometric morphometric protocols. Even if they belong to different haplogroups all wild mice shared a similar inner ear morphology, contrasting with the important divergence of the Swiss strain. The release of selection in the laboratory strain obviously allowed for an important drift of the otherwise conserved structure. Hybrids displayed a morphology close to the wild parents, suggesting an accumulation of recessive and presumably unfavorable alleles in the laboratory strain. Contrary to the expectation, however, wild mice displayed slightly higher levels of inter-individual variation compared to lab mice, possibly due to the higher levels of genetic variance within and among wild populations compared to the lab strain. Differential allometric response of the different canals was also documented; the wide age range documented in wild mice could also contribute to increased morphological variance.