Sympatric sister species in rodents are more chromosomally differentiated than allopatric ones: implications for the role of chromosomal rearrangements in speciation

A meta-analysis approach was used to test for chromosomal speciation in rodents. Forty-one pairs of sister species, identified in the two most species-rich rodent families (Cricetidae and Muridae), were used as phylogenetically independent data points, each resulting from a speciation event. About 30% of sister species have an identical karyotype. There was a significant difference in the number of chromosomal differences between sympatric and allopatric sister species, compatible with a direct role of chromosomal rearrangements in speciation.