Genetic Divergence and Molecular Phylogenetic Analysis of Rainbow Trout, Oncorhynchus mykiss (Walbaum, 1792), From the Indian Upland Coldwater Regions

The popular coldwater fish, the rainbow trout Oncorhynchus mykiss (Walbaum, 1792), was first brought to the Indian subcontinent in the 20th century and was established in the coldwater upland regions. This study examines the molecular phylogenetic linkages and genetic divergence of the O. mykiss that was introduced in India's North-Western Himalayas and Southern Western Ghats. The genetics of Indian O. mykiss are compared with Pacific trout in the genus Oncorhynchus. Twenty-two accessions were gathered from four distinct geographic regions, and the nBLAST homology method was used to analyse the 650 bp mtDNA COX1 segment. The results showed an intra-species divergence of 0.0 %–0.4 %, which confirms the study species to be O. mykiss. However, including nine other Oncorhynchus populations from the Pacific lineage resulted in an inter-species divergence of 0.2 % to 1.7 %. Phylogenetic analysis by the Bayesian and BEAST methods showed a distinct lineage of Pacific trout and salmon groups in separate clades. The phylogenetic trees obtained confirmed that O. clarkii was a sister clade to O. mykiss, O. gilae, and O. g. apache. All of the Pacific salmonid species were clearly distinguished from the clade that contained the Indian O. mykiss stocks. The study's findings fill the current knowledge gap about the genetic composition of Indian O. mykiss stocks in comparison to other stocks throughout the world and provide insight into how to manage the genetic variety of Indian O. mykiss stocks.