Different behaviour of mitochondrial and nuclear markers: introgression and the evolutionary history of <i>Chrysocarabus</i> (Coleoptera: Carabidae)

Phylogenetic analyses of Chrysocarabus taxa using different markers result in different phylogenetic trees. In particular, the mitochondrial gene tree contradicts the results of morphological and inbreeding studies. Two very different haplotypes of Carabus splendens Olivier, 1790 do not form a clade within this phylogenetic tree. We have earlier proposed that contradictory results are due to introgression. To verify our hypothesis, we analysed the internal transcribed spacer 2. No substitutions were observed in these nuclear sequences between the individuals of Carabus splendens, which contain the different mitochondrial haplotypes in question. The differences in the gene trees based on mitochondrial and nuclear sequences can be explained with at least two introgression events.