Population Genetic Structure and Genetic Diversity of Cobia (Rachycentron canadum) in the Persian Gulf and Makran Sea

The population structure and genetic diversity of Cobia (Rachycentron canadum) fish were studied in the Persian Gulf and Oman Sea using AFLP molecular markers. In the present study, 70 samples were collected from the Persian Gulf (Bushehr, Hendijan, and Dayyer) and 2 regions of the Makran Sea (Bandar Abbas and Chabahar). The results indicated that 557 loci were amplified by 10 pairs of primers and 243 loci showed polymorphism. An average of 43.6% of polymorphic loci was amplified for each primer combination. The genetic average diversity was 0.29. The highest and lowest genetic diversities were observed in the samples obtained from Chabahar (0.37) and Bushehr, respectively. Variance analysis showed that there was a significant difference between the studied populations in terms of genetic diversity. The coefficient of genetic differentiation between the populations (FST) ranged from 0.024 to 0.204 indicating a low level of gene differentiation within the population in the Persian Gulf, while gene differentiation between the populations in the Persian Gulf and Makran Sea was intermediate. The genetic distance and phylogenetic tree showed a clear pattern of the separation of populations of the Persian Gulf and Makran Sea. Gene flow (Nm) between the populations was measured to be 0.93-10.6 based on the genetic differentiation coefficient between the populations, indicating that there was l gene flow between the populations. Therefore, the results of clustering, genetic distance, Fst index, and PCA analysis revealed that the Persian Gulf populations were not separated, but they were separated from Jask and Chabahar populations.