Advancing DNA Barcoding to Elucidate Elasmobranch Biodiversity in Malaysian Waters

Area of Science:

• Marine biology and genetics
• Ichthyology
• Molecular ecology

Background:

• Accurate identification of shark and batoid species is crucial for fisheries management and conservation.
• Existing data on elasmobranch diversity in Malaysian waters may be incomplete.
• Mitochondrial DNA barcoding, specifically the Cytochrome c oxidase subunit 1 (CO1) gene, is a standard method for species identification.

Purpose of the Study:

• To generate partial CO1 gene sequences for sharks and batoids from Malaysian waters.
• To authenticate species identification and assess genetic diversity within and among taxa.
• To establish a comprehensive CO1 database for Malaysian elasmobranchs to support future research and conservation efforts.

Main Methods:

• DNA extraction from 175 tissue samples using Chelex protocol.
• Amplification of the CO1 gene using polymerase chain reaction (PCR) with universal primers FishF2 and FishR2.
• Sequencing of 654 base pairs (bp) of the CO1 gene and analysis via BLAST searches against NCBI GenBank and Barcode of Life Data System (BOLD).

Main Results:

• Generated CO1 barcodes for 67 species across 20 families and 11 orders.
• Confirmed the presence of 68 valid shark and batoid species in Malaysian waters.
• Identified four new species records for Malaysia: *Squalus edmundsi*, *Carcharhinus amboinensis*, *Alopias superciliosus*, and *Myliobatis hamlyni*.

Conclusions:

• The study successfully expanded the CO1 gene database for Malaysian sharks and batoids.
• Phylogenetic analyses and genetic distance calculations provided insights into elasmobranch evolutionary relationships.
• The established database will facilitate rapid species identification and monitoring of elasmobranch fisheries using environmental DNA (eDNA) methods.