Determination of the genetic diversity of rainbow trout (oncorhynchus mykiss) populations breeding in different provinces in Turkey by sequence analysis from the MTDNA region

This study examines the genetic diversity and structure of commercially active rainbow trout (Oncorhynchus mykiss) populations in various provinces of Turkey, based on the mitochondrial DNA (mtDNA) cytochrome b (cyt-b) gene region. In the study, a 754 base pair (bp) segment of the cytochrome b gene was amplified from samples taken from 98 individuals across 14 provinces, and a 726 bp sequence was analyzed after alignment. The average frequencies of the four nucleotides (cytosine, thymine, adenine, and guanine) were found to be 26.2%, 24.9%, 26.2%, and 22.8%, respectively; it was determined that the A + T content (51%) was higher than the G + C content (49%). A total of 645 polymorphic loci were identified across the 14 populations, and 50 different haplotypes were defined. Haplotype diversity (Hd) ranged from 0.91 to 0.48, while nucleotide diversity (π) varied from 0.26 to 0.00. The highest genetic diversity was observed in the Tokat and Van populations, while the lowest was seen in the Elazığ and Kahramanmaraş populations. AMOVA analyses showed that 71.1% of the genetic diversity was among populations, while 28.9% was within populations. Pairwise FST values ranged from 0.38 to 0.99, with an average FST value of 0.71, indicating high genetic differentiation between populations. Phylogenetic analyses revealed that the populations were divided into two main groups, which further formed distinct subgroups. Notably, the Kahramanmaraş and Elazığ populations were found to be significantly differentiated from the other populations. In conclusion, these findings provide important information on the genetic diversity and structure of rainbow trout populations in Turkey. The study highlights the importance of preserving genetic diversity for the conservation and sustainable management of these populations. It also provides valuable information for future genetic research and conservation strategies, emphasizing the need for long-term monitoring programs.