DNA barcoding and phylogenetic analysis of five ascidians (Phlebobranchia) distributed in Gulf of Mannar, India.

DNA barcoding has played a significant role in biodiversity assessment as well as its conservation. This technique involves sequencing of mitochondrial marker gene including a short COI gene, known as barcode gene. It has proved its efficiency in identifying several species and resolving the limitations incurred during identification through conventional taxonomy. This study involves the use of DNA barcoding of ascidian species belonging to order Phlebobranchia. A total of 14 individuals, covering two families, three genera and five species, were barcoded. COI gene sequences of all the five species were deposited for the first time in NCBI as well as BOLD. The NJ tree revealed identical phylogenetic relationship among the individuals collected from three different stations. Mean Kimura 2-parameter (K2P) distances within-species, genus, family and order were 0.08%, 6.69%, 9.49% and 18.58%, respectively. This result concludes that COI gene sequencing is the efficient tool in identifying ascidians of the order Phlebobranchia. We report for the first time the COI gene sequences of four species of ascidians studied.