A rapid PCR-RFLP method for species identification of the eastern Pacific horn sharks (genus Heterodontus)

Abstract

Accurate species identification is essential for the successful implementation of species conservation strategies and research. East Pacific horn sharks (genus Heterodontus) may be subject to overfishing and depletion in some areas, mandating an assessment of risk and vulnerability to exploitation. Unfortunately, morphological identification of the three eastern Pacific species can be challenging, creating uncertainty about species identifications and the true extent of their respective ranges. To address this problem, we developed a PCR-RFLP method to quickly and accurately identify the three species of Heterodontus occupying the coastlines and islands of the eastern Pacific (H. francisci, H. mexicanus, and H. quoyi). The PCR-RFLP assay requires only a single amplification of the mitochondrial NADH2 locus (1216 bp) and a single digestion step with restriction enzyme AluI. The assay was tested on 67 individuals representing all three species and resulted in unambiguous species identification for 100% of individuals tested.