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Identifying Sharks With DNA Barcodes: Assessing the Utility of a Nucleotide Diagnostic Approach
Molecular Ecology Resources
  • Eugene H.-K. Wong, University of Guelph - Canada
  • Mahmood S. Shivji, Nova Southeastern University
  • Robert H. Hanner, University of Guelph - Canada
Document Type
Publication Date
  • DNA barcoding,
  • Sharks,
  • Single nucleotide diagnostics
Peer Reviewed
Shark fisheries worldwide are mostly unmanaged, but the burgeoning shark fin industry in the last few decades has made monitoring catch and trade of these animals critical. As a tool for molecular species identification, DNA barcoding offers significant potential. However, the genetic distance-based approach towards species identification employed by the Barcode of Life Data Systems may oftentimes lack the specificity needed for regulatory or legal applications that require unambiguous identification results. This is because such specificity is not typically realized by anything less than a 100% match of the query sequence to an entry in the reference database using genetic distance. Although various divergence thresholds have been proposed to define acceptable levels of intraspecific variation, enough exceptions exist to cast reasonable doubt on many less than exact matches using a distance-based approach for the identification of unknowns. An alternative approach relies on the identification of discrete molecular characters that can be used to unambiguously diagnose species. The objective of this study was to assess the performance differences between these competing approaches by examining more than 1000 DNA barcodes representing nearly 20% of all known elasmobranch species. Our results demonstrate that a character-based, nucleotide diagnostic (ND) approach to barcode identification is feasible and also provides novel insights into the structure of haplotype diversity among closely related species of sharks. Considerations for the use of NDs in applied fields are also explored.

This research was supported through funding to the Canadian Barcode of Life Network from Genome Canada (through the Ontario Genomics Institute), NSERC and other sponsors (listed at

Citation Information
Eugene H.-K. Wong, Mahmood S. Shivji and Robert H. Hanner. "Identifying Sharks With DNA Barcodes: Assessing the Utility of a Nucleotide Diagnostic Approach" Molecular Ecology Resources Vol. 9 Iss. Supplement 1 (2009) p. 243 - 256 ISSN: 1755-098X
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