Molecular Genetic Approaches for Species Identification
Mike Canino and Troy Buckley have been awarded a North Pacific Research Board (NPRB) grant to develop rapid, accurate, DNA-based identification methods for fish larvae and dietary components, with particular emphasis on taxonomic groups where traditional approaches are difficult, time consuming, and fail to identify to the species level.
Routine application of these powerful molecular genetic methods in research conducted at the AFSC will allow for more accurate, timely, and cost-efficient species identification. Accurate identification of life history stages of marine fishes is central to understanding their distribution and abundance.
Conventional taxonomic approaches have been successfully used for ichthyoplankton identification by Recruitment Processes Program scientists for many years. However, diagnostic characters for eggs or larvae in some species have not been determined, making it impossible to accurately identify them below the genus, and sometimes family level.
AFSC scientists Mike Canino and Ingrid Spies have developed molecular genetic techniques that utilize fixed nucleotide differences in the mitochondrial DNA (mtDNA) genome for species identification.
A restriction length fragment polymorphism (RFLP) protocol of the mtDNA cytochrome oxidase subunit I (COI) region was developed to identify eggs and larvae of Arrowtooth flounder, Atheresthes stomias, and Kamchatka flounder, A. evermanni, and was used in the NPRB-cofunded Bering Sea Integrated Ecosystem Research Program (BSIERP) to identify larvae of these two species at sea.
The RFLP technique was successful in identifying the life history stages of these two species at sea. Tissue requirements for the assay were minimal (one eyeball per larva), allowing us to sort larvae to species for more rigorous taxonomic comparisons, descriptions, and illustrations.
