A simple restriction fragment length polymorphism (RFLP) assay to discriminate common Porphyra (Bangiophyceae, Rhodophyta) taxa from the Northwest Atlantic

The identification of Porphyra species has historically been difficult because of the lack of distinguishing morphological and ecological characters. We developed a restriction fragment length polymorphism (RFLP) assay, based on inter-specific sequence variation in the ribulose bisphosphate carboxylase oxygenase large subunit (rbcL) gene and rbcL-rbcS intergenic spacer, to provide a simple and effective tool for screening and sorting large collections of Porphyra from the Northwest Atlantic. A single restriction digest (Hae III) discriminates between multiple Porphyra species including one cryptic taxon; an additional enzyme (Hind III) was necessary to distinguish between the closely related P. leucosticta and an introduced species P. yezoensis.