Genetic analysis of Phoxinus strandjae (Drensky, 1926) population in Turkish inland water

Genetic identification, historical demographics and population genetic structure of Phoxinus (Cyprinidae: Teleostei) populations was characterized using the sequence variation in the mitochondrial 16S rRNA (167 bp), cytochrome c oxidase subunit I (652 bp), cytochrome b (1140 bp) gene sequences of 67 individuals from six populations in Thrace, South Marmara and Black Sea River basin, Turkey. Low haplotype number, haplotype and nucleotide diversity values, the haplotype network and phylogenetic tree topologies (NJ, MP and ML) pointing to the existence of the disappearing haplotypes are compatible and suggest to a recent or ongoing bottleneck event in the Phoxinus populations of North-western Turkey. However, the multimodal mismatch distribution, the negative and non significant Tajima's D values and Fu's Fs values and long branch lengths on a phylogenetic trees are consistent with each other, indicating that subpopulations are in the long-term Hardy-Weinberg equilibrium. Pairwise genetic distances between populations, the median joining network and the phylogenetic trees exhibited a population genetic structure consisting of four haplogroups (KLK-HDK/ABT/RZV/SGK-PYL). Similarly, FST and AMOVA statistics have shown that significant genetic variation is observed among these four groups. We observed a high FST values and low gene flow (FST > 0.44, Nm<1) suggesting low genetic exchange and significant differentiation between the four geographical population groups. The AMOVA performed among the four population groups showed highly significant genetic differentiation (FST > 0.44, p-value >0.05). Considering the widely used Cytb calibration rate for fish (1.05%), levels of divergence for population of Thrace and Anatolia suggest that they are isolated from each other during Pliocene (about 2 Mya), after the opening of İstanbul and Dardanalles straits.