A DNA barcode examination of the Laminariaceae (Phaeophyceae) in Canada reveals novel biogeographical and evolutionary insights

Abstract

DNA barcoding is becoming a widely applied tool for the rapid and accurate identification of eukaryotic species. In this study we used the DNA barcode for large-scale screening of the brown algal family Laminariaceae in Canada. With the examination of 194 COI-5P (59 end of cytochrome c oxidase 1) sequences (150 newly determined) from representatives of this family, we confirmed the presence of 12 species in Canadian waters (Cymathaere triplicata, Laminaria digitata, L. ephemera, L. setchellii, L. solidungula, L. yezoensis, Macrocystis integrifolia, Nereocystis leutkeana, Postelsia palmaeformis, Saccharina groenlandica, S. latissima and S. sessilis). Saccharina groenlandica, a species with a history of taxonomic confusion, was found in the Pacific, Hudson Bay (subarctic) and Atlantic Canada extending greatly our comprehension of the biogeography of this species. Additionally, COI-5P data from S. latissima, combined with ITS results, provided insights into historical distributional patterns and uncovered a hybridization zone between incipient species in this complex. These discoveries highlight how the growth of a worldwide barcode database for the assignment of individuals to genetic species will uncover new perspectives on biogeography and species diversity on a global scale.

Ligulate Desmarestia (Desmarestiales, Phaeophyceae) revisited: D. japonica sp. nov. and D. dudresnayi differ from D. ligulata

“…However, the ITS marker crucially lacks resolution and there is only 0.2% separating species and genus. The genetic distances for Desmccrestia ITS barcodes were similar to those of Saccharina latissima and Laminariales, whose species cut-off was greater than 1% (McDevit and Saunders 2010). The lack of species/genus separation was also observed for S. la tissima (Linnaeus) C.E.…”

“…Lane, C. Mayes, DruehJ et G.W. Saunders, where the biogeographical boundaries established u~ing cox1-barcodes had collapsed using ITS-barcodes, with the authors speculating introgression as the cause (McDevit and Saunders 2010). It is possible that a lack of resolution in the ITS barcodes of Desmarestiales have occurred for similar reasons.…”

“…In Phaeophyceae, DNA barcoding has been successful in identifying new and cryptic species. Mitochondrial cox1 and the nuclear rRNA ITS have been successful in identifying many brown algal species belonging to the Laminariales (Lane et al 2007, Macaya and Zuccarello 2010, McDevit and Saunders 2010 and Fucales (Kucera andSaunders 2008, McDevit andSaunders 2009). The cox1 locus reveals biogeographic patterns and cryptic diversity, but it is not uniformly useful in all Phaeophyceae, such as Macrocystis (Macaya and Zuccarello 2010).…”

Will a DNA barcoding approach be useful to identify Porphyra species (Bangiales, Rhodophyta)?

“…Saunders (2005) has adapted this marker for application in the Rhodophyta, which was later extended to the Phaeophyceae (Kucera and Saunders 2008;McDevit and Saunders 2010). The increasing number of published articles using the cox1 indicates the success of this marker for both red and brown macroalgal identification at the species level, with a wide range of applications (Saunders 2008(Saunders , 2009Walker et al 2009;Clarkston and Saunders 2010;Le Gall and Saunders 2010).…”

Relative importance of kelps and fucoids as substrata of the invasive epiphytic bryozoan Membranipora membranacea in Nova Scotia, Canada

“…Previous research in the northwest Atlantic Ocean has focussed on the occurrence of Membranipora mem branacea on kelps, specifically Saccharina latissima (formerly S. longi cruris; McDevit & Saunders 2010) and Laminaria digitata , Levin et al 2002, Scheibling & Gagnon 2006, Saunders & Metaxas 2007, 2008, 2009a. However, M. membranacea occurs on various biotic and abiotic substrata throughout its range and, in addition to various kelp species, it also occurs on other algae.…”