DNA BARCODING OF THE ORNAMENTAL SNAKEHEAD FISHES OF INDIA

The family Channidae present 49 valid species, comprises two genera: Channa, with 46 valid species distributed from the Middle East to Asia, and Parachanna with 3 species restricted to Africa. Channa sp. popularly known as snakeheads are medium-sized to large predatory freshwater teleosts belonging to the family Channidae. From India, there are 21 valid species of snakeheads, 19 of which are known from the Eastern Himalayan region. The colorful ones are popular in the aquarium fish trade and are exclusively exported from India and fetch a good price ranging from 750 - 50,000 INR /fish Many of this species demonstrate phenotypic plasticity and makes one hard to identify at species level. Hence, DNA barcoding is the important tool for species discrimination, identification of cryptic species, and indirectly plays a key role in conservation of endangered species.

In the present study, DNA barcoding of the ornamental snakeheads of Indian origin were done to synthesis DNA barcodes for accurate species identity. DNA extraction was done from one individual of Channa bleheri, C. andrao, C. lipor, C.  stewartii, C.  pomanensis, C.  gachua, C. bipuli, C. quinquefasciata and C. royi, by using QIAGEN blood and tissue kit. Partial cytochrome oxidase unit I (coxI) gene of about 630 bp were amplified by PCR conditions. The amplified PCR products were sequenced. Gene sequences were aligned using MUSCLE (Edgar 2004). The maximum likelihood (ML) phylogenetic tree was constructed using MEGAX. Based on the lowest BIC (Bayesian Information Criterion), the best fit nucleotide substitution model (out of  24 models) for the 41 COI dataset is TN93+G+I given by Tamura & Nei (1993) (Tamura-Nei + Gamma distribution with 5 rate categories + certain fraction of sites are evolutionarily invariable). Reliability of the phylogenetic tree was estimated using bootstrap values run for 1000 iterations.

The cytochrome oxidase unit 1 gene sequences clearly discriminated the intraspecific genetic variations among the snakeheads by means of the phylogenetic analysis (Fig1.). The generated barcodes for 10 species of snakehead can be used for BLAST analysis confirmation for accurate species identity (Fig. 2).