摘要：Graphical abstractDisplay OmittedAbstractCytochromecoxidase I (COI) is one of the mitochondrial genes, an excellent marker used for the DNA barcoding of various organisms. The COI was isolated from twelve different species of waterbirds using the Gene Elute DNA miniprep Kit. The relationship among the waterbirds was assessed by making a phylogenetic tree with the software MEGA-X. The phylogenetic tree's dendrogram showed two main branches in which seven species of water birds aligned one group with four subgroups and the remaining five species aligned with two subgroups based on their similar COI sequences. The Little egret showed 96% similarity with the Cattle egret, Purple heron and Oriental Darter produced 94% similarity with the Grey heron, pond heron shared 90% similarity with the Black-crowned night heron, Asian openbill shared 89% with Pheasant-tailed Jacana and the Common coot 94% similarity with White-breasted waterhen. The pond heron and the Black-crowned night heron showed zero % pairwise distance, but the Cattle egret, Little egret, Oriental Darter, Purple heron and Grey heron showed < 0.29%. However, the other seven species of water birds showed > 12% of the pairwise distance. Twenty-one conserved haplotypes have been shown in their COI sequences based on the multiple sequences alignment. DNA barcoding identifies the species with their genetic property rather than based on their ecology and behvaviour.
