Mitochondrial gene sequences useful for species identification of western North Atlantic Ocean sharks

Molecular-based approaches for shark species identification have been driven largely by issues specific to the fishery. In an effort to establish a more comprehensive identification data set, we investigated DNA sequence variation of a 1.4-kb region from the mitochondrial genome covering partial sequences from the 12S rDNA, 16S rDNA, and the complete valine tRNA from 35 shark species from the Atlantic fishery. Generally, within-species variability was low in relation to interspecific divergence because species haloptypes formed monophyletic groups. Phylogenetic analyses resolved ordinal relationships among Carcharhiniformes and Lamniformes, and revealed support for the families Sphyrnidae and Triakidae (within Carcharhiniformes) and Lamnidae and Alopidae (within Lamniformes). The combination of limited intraspecific variability and sufficient between-species divergence indicates that this locus is suitable for species identification.