Building a Better DNA Guide for South Africa’s Sharks and Rays

South African waters host an impressive array of sharks, rays, and related species.
Scientists are now tracking these animals using tiny DNA fragments that drift in the sea—a technique called eDNA metabarcoding.
Accurate identification hinges on reference libraries that link DNA sequences to known species.

Why 12S rRNA Matters

• Common barcode gene: COI is widely used for animal barcoding.
• Shark & ray specialist: 12S rRNA provides better resolution for chondrichthyans.
• Current gap: Existing 12S libraries for South African species are incomplete, hindering sample identification.

The Research Effort

1. Sample collection – Tissue samples gathered from numerous chondrichthyan species along the coast.
2. Sequencing – 12S rRNA genes were sequenced from each specimen.
3. Database expansion – New sequences added to the reference library, creating a more robust dataset.

Impact

• Higher confidence in eDNA species detection.
• Benefits extend beyond South Africa, aiding researchers worldwide who study these widely roaming species.
• Demonstrates how expanding a single gene’s reference set can elevate biodiversity monitoring and underscores the value of region‑specific data for global conservation.