DNA BARCODES TO STUDY DIVERSITY AND SPECIES COMPOSITION OF CLAMS FOUND IN AND AROUND MUMBAI COAST.

Abstract

There are diverse aquatic animals living in broad range of habitats and niches and studying their diversity by morphological dataset has been a point of debate for many years because of their varied forms. However, DNA barcoding technique which originated in the last decade has helped for expanding the horizons of biodiversity science. In the present study, diversity of marine clams found in coastal area of Mumbai, India was studied and it was found that mitochondrial cytochrome c oxidase subunit I (COI) gene based identification of marine clam species has lower success rate (60%) in existing circumstances, which is, enough to disclose differently located species. Consequently, 4 species (Gafrarium divaricatum, Geloina erosa, Meretrix casta, Tegillarca granosa) and 1 family (Tellinidae) of clams collected from 6 locations were studied using platforms of the studied molecular marker and morphological database. Results showed that BOLD systems v4 and NCBI databases could generate 40.74% and 85.18% identification success of 54 clams under investigation, respectively. Moreover, the analyzed specimens formed distinct cohesive species-specific clusters using Neighbor Joining (NJ) tree. The maximum intraspecific genetic variation was 2.54% (SE 0.00%) which supported reliability of species delimitation and the barcode gap analysis using Automated Barcode Gap Discovery (ABGD) and BOLD analytical tool revealed explicit species distinction. A mixed prevalence was observed of investigated species of Mumbai coast with suspected threat of endangerment and extinction. It may be concluded that DNA barcode based analysis of Indian marine clams may be effectively used for robust identification of species with varied macro habitats in the presence of enough COI reference sequence library, thus assisting marine biodiversity investigation and conservation.