Population Genetic Structure of Petroleuciscus borysthenicus (Kessler 1859) in Northwestern Türkiye Using Mitochondrial COX1 Gene

Petroleuciscus borysthenicus is a species with a wide distribution from the eastern, western, and northern Black Sea and Azov Sea basins, the Aegean Sea basin, and Northwestern Türkiye. However, there has been relatively little attention on the genetic variability of this species in their native distribution range, and nearly no study has been conducted in Türkiye despite its importance in biodiversity. The aim of this study was to elucidate the genetic variability and population structure of P. borysthenicus from Northwestern Türkiye using an integrated molecular method. A total of 72 specimens were collected from 13 localities in the Northwestern part of Türkiye. A total of six haplotypes were identified in all specimens. A relatively low level of genetic variability was found for P. borysthenicus throughout the study region based on the indices of genetic diversity including haplotype diversity and nucleotide diversity for the cytochrome oxidase subunit I (h = 0.507, π = 0.0027). The pairwise F_ST values between the samples ranged from −0.123 to 1.000. Furthermore, our results revealed no provable recent demographic expansion for P. borysthenicus from Northwestern Türkiye. However, more studies using additional geographic sampling and molecular analysis are needed to enhance our knowledge of the diversity and distribution of this species.