a tri-oceanic perspective dna barcoding reveals geographic structure and cryptic diversity in canadian polychaetestri-oceanic角度dna条码技术揭示地理结构和在加拿大多毛类神秘的多样性.pdfVIP

A Tri-Oceanic Perspective: DNA Barcoding Reveals Geographic Structure and Cryptic Diversity in Canadian Polychaetes 1 2 3 3 1 Christina M. Carr *, Sarah M. Hardy , Tanya M. Brown , Tara A. Macdonald , Paul D. N. Hebert 1 Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada, 2 University of Alaska, School of Fisheries and Ocean Sciences, Fairbanks, Alaska, United States of America, 3 Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, Canada Abstract Background: Although polychaetes are one of the dominant taxa in marine communities, their distributions and taxonomic diversity are poorly understood. Recent studies have shown that many species thought to have broad distributions are actually a complex of allied species. In Canada, 12% of polychaete species are thought to occur in Atlantic, Arctic, and Pacific Oceans, but the extent of gene flow among their populations has not been tested. Methodology/Principal Findings: Sequence variation in a segment of the mitochondrial cytochrome c oxidase I (COI) gene was employed to compare morphological versus molecular diversity estimates, to examine gene flow among populations of widespread species, and to explore connectivity patterns among Canada’s three oceans. Analysis of 1876 specimens, representing 333 provisional species, revealed 40 times more sequence divergence between than within species (16.5% versus 0.38%). Genetic data suggest that one quarter of previously recognized species actually include two or more divergent lineages, indicating that richness in this region is currently underestimated. Few species with a tri-oceanic distribution showed genetic cohesion.