Genetic analysis of barbus populations in Eastern Anatolia

The phylogeography and phylogenetic relationships of Barbus species throughout the eastern Anatolia was established by genetic variation at the partial mitochondrial cytochrome b gene (936 bp). The study of 90 specimens from 15 localities representing seven Anatolian drainage systems served to identify a total 23 haplotypes and five main lineages of mitochondrial haplotypes. The high haplotype (h = 0.760 - 0.879) and low nucleotide (π = 0.214 - 0.395) variability values determined for each species except for B. escherichii and several haplotypes representing almost equal numbers of individuals in each species are linked together by 1 or 2 mutational steps show that there was not enough time to accumulate large nucleotide differences in haplotypes after population expansion. The constructed phylogeny shows three well supported main clades: Black sea, Caspian and Persian gulf basin within eastern Anatolian Barbels. According to evolutionary rate of 1% per million years for cyprinids, these clades diverged from each other Late Pliocene (3.34 to 2.9 mya) consistent with the timing of Pliocene-Pleistocene sea level changes and orogenic activities in East Anatolia. This period coincides with rise of the region, which is the intersection of the present Coruh, Aras and Upper Euphrates basins, following the formation of the Pontids. On the other hand, our results revealed that three Barbus lineages in Anatolia rivers flowing to the BlackSea diverged from each other about 5.77 to 1.37 Mya. We conclude that the Barbus lineages of the modern Black Sea originated from several Pontic glacial refugium, each of the refugee population may have a distinct evolutionary history and have survived until today without changing much despite global climatic fluctuations and environmental changes characterizing the late Pleistocene.