Short Communication - Genetic Structure Analysis of Freshwater fish Cirrhinus mrigala by Mitochondrial COI Gene

The current study aimed at genetic analysis of by Cirrhinus mrigala using mitochondrial DNA marker cytochrome oxidase I (COI). Genomic DNA isolated from whole blood was used to amplify and sequence a short region of COI gene in mitochondrial DNA. The identification of sequenced samples was done by NCBI (98-99%) and BOLD (99%) databases. The sequence data analysis represented 15 variable polymorphic sites and 4 haplotypes. Mean haplotypes and nucleotide diversity was 0.42 and 0.0018, respectively. The mean intraspecific and intragenric K2P genetic distances were 0.2% and 1.2%, respectively. Rate of transitional and transversional substitution was 16.68% and 4.16%, respectively. The transition/transversion bias value R was 1.25. The negative values of Tajima D test as well as Fu and Li D and F tests supported the process of population expansion with excess of rare alleles. The overall results showed a lack of neutral evolution and low genetic differentiation among populations of C. mrigala. Keywords: Cirrhinus mrigala, COI gene, K2P genetic distances, Population expansion Identification of fish stock is very important for successful and sustainable management. Identification is usually done through phenotypic characters instead of genetic differentiation. It may lead to mislabeling of fish species. So morphometric plus molecular approach is highly recommended for the authentic identification of any species as both the factors are very helpful in efficient recognition and discrimination of species. Precise knowledge about population genetic structure is vital for its sustainable growth as well as its conservation status (Shui et al., 2009). There is a great biodiversity among fish fauna of world. This fish fauna exhibit substantial morphological variation at various stages of development that leads to DNA barcoding a striking technique for identification (hubert et al., 2008). DNA barcoding is also used for authentication of mislabeled seafood as well as recognition of species specific contaminants in fish products that can cause serious illness to humans (Ward et al., 2009; Lowenstein et al., 2010). The barcode sequence obtained from fish, fillet, fin, eggs and larvae can be matched against reference sequences on Barcode of Life Database System for proper identification (http://www.barcodinglife.org). The present study was conducted to identify the freshwater fish Cirrhinus mrigala at molecular level, which is commonly cultured in freshwater reservoirs of Pa