Geometric morphometrics on Greek house mouse populations (Mus musculus domesticus) with Robertsonian and all-acrocentric chromosomal arrangements

This work aims to give the first comprehensive morphometric analysis of intraspecific variation for the different populations of the western house mouse (Mus musculus domesticus), in the Robertsonian (Rb) system of the N-NW Peloponnisos. Furthermore, we study all-acrocentric karyotype populations (2n = 40) of the species coming from several localities of Greece. We apply 2D shape analysis, i.e. landmark analysis and Elliptic Fourier Analysis, on the dorsal and ventral side of skull and the occlusal view of the first upper molar (M1), respectively. Although significant genetic divergence between typical and Rb populations and even ongoing speciation processes have been reported for this species, this was not the case for the Greek populations studied. However, our analyses herein reveal morphologically differentiated chromosome groups in N-NW Peloponnisos Rb system and a clear geographical discrimination of the all-acrocentric (2n = 40) populations for all characters studied. We suggest that in all-acrocentric (2n = 40) karyotype mice the geographical distance drives their differentiation while within the Rb system of N-NW Peloponnisos, karyotype is the key factor that acts on their phenotypic variation.