Role of contact areas in chromosomal speciation of the European long-tailed house mouse (Mus musculus domesticus)

Abstract

Chromosomally rearranged populations of house mouse (Mus musculus domesticus) with different diploid numbers (2n=26, 24 and 22), come into contact both inter se and with the 40-chromosome unchanged populations surrounding them, giving rise to tension zones in the sense used by Key. The evolutionary role of contact areas was emphasized as essential steps during the accumulation phase of chromosomal (Robertsonian) rearrangements as well as a key element in the chromosomal post-mating isolation. The structure and the dynamics of the hybridization zones, between 40-chromosomes and Robertsonially rearranged mouse populations, were studied and the possibility of gene flow was tested analyzing the allozymic variation; a speciation model was proposed for Mus musculus domesticus on the basis of its chromosomal intraspecific variability.