Matrilinear phylogeography and demographical patterns of Rutilus rutilus: implications for taxonomy and conservation.

A phylogeographic analysis of mitochondrial DNA sequence variation was carried out to infer the geographical distribution of the genealogical lineages and the historical demography of roach Rutilus rutilus (L.). A total of 265 individuals from 52 sites covering most of the Eurasian distribution range were sequenced for a 475 bp fragment of the mitochondrial cytochrome b gene. The monophyletic roach contained two deep clades that dated back to the Pliocene. The Ponto-Caspian clade comprised populations from Greece to Siberia with a likely palaeorefugium at the west coast of the Caspian Sea. This clade largely corresponds to individuals with morphological features described as Rutilus heckelii. The west European clade included individuals from central and western Europe with the Danube and Dniester basins as possible palaeorefugia. This clade largely corresponds to individuals with morphological features described as R. rutilus. A suture-zone of the two main lineages was observed along the coastal region of the Black Sea. The neutrality tests and the mismatch distributions indicated a demographic expansion during the Middle-Pleistocene for both clades.