Molecules and morphology: evidence for introgression of mitochondrial DNA in Dalmatian cyprinids.

In one population of Scardinius dergle, mitochondrial DNA was observed originating from Squalius tenellus. Scardinius dergle shared all diagnostic morphological characters and similarities at a highly variable nuclear region with the genus Scardinius. While crosses and backcrosses most likely resulted in the loss of morphologically diagnostic Squalius-features, maternal inheritance of mtDNA fixed their diagnostic substitutions. Anthropogenic influences resulting from dam building in 1962 are suspected to be the initial force for the hybridization events. However, because hybridization took place despite both lineages being only very distantly related (p=11.2%), we conclude that introgressive hybridization events can be seen as generally possible among leuciscine cyprinids.