A molecular assessment of northeast Pacific Alaria species (Laminariales, Phaeophyceae) with reference to the utility of DNA barcoding

  • Lane C
  • Lindstrom S
  • Saunders G
  • 138

    Readers

    Mendeley users who have this article in their library.
  • 102

    Citations

    Citations of this article.

Abstract

Despite their relatively complex morphologies, species in the genus Alaria Greville are notoriously difficult to identify with certainty. Morphological characters, often influenced by environmental factors, make individuals in similar habitats artificially appear related. Species identification would, therefore, benefit greatly from the application of molecular tools. We applied DNA barcoding, using the 5′ end of the cytochrome c oxidase I (coxI-5′) gene from the mitochondrial genome, to define species limits and relationships in northeast Pacific populations of Alaria. This emerging technique is being employed to catalogue species diversity worldwide, particularly among animals, and it has been shown to be sensitive enough to discriminate between closely related species. However, the utility of this marker for identifying or categorizing the majority of life remains unclear. We compared the resolution obtained with this marker to two other molecular systems commonly used in algal research: the nuclear internal transcribed spacer (ITS) of the ribosomal cistron, and the plastid Rubisco operon spacer (rbcSp). In agreement with previous results, Alaria fistulosa Postels & Ruprecht, with its distinct morphological, ecological and molecular features, stands apart from the other species in the genus and we establish Druehlia gen. nov. to accommodate it. For the remaining isolates, distinct mitochondrial haplotypes resolved with the barcode data indicate a period of genetic isolation for at least three incipient species in the northeast Pacific, whereas unexpected levels and patterns of ITS variation, as well as the extreme morphological plasticity found among these isolates, have most probably resulted from a recent collapse in species barriers. The cloning of ITS amplicons revealed multiple ITS copies in several individuals, further supporting this hypothesis. © 2007.

Author-supplied keywords

  • Alaria
  • DNA barcode
  • Druehlia
  • ITS
  • Pacific
  • Rubisco spacer
  • coxI-5′

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Christopher E. Lane

  • Sandra C. Lindstrom

  • Gary W. Saunders

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free