• Browse
    • Author
    • Year
    • Platform
    • Organizations
    • Programs
    • Research Networks
    • Type
  • Search
    • Simple
    • Advanced
  • About
    • About
    • Policies
    • Citation Guide
  • Login
    Logo Alfred Wegener Institut
    Logo Alfred Wegener Institut
    Alfred-Wegener-Institut
    Helmholtz-Zentrum für Polar-
    und Meeresforschung
    • Imprint
    • Contact
    • OAI
    • RSS 2.0

    EPIC.awi.de

    Home
    • Browse
      • Author
      • Year
      • Platform
      • Organizations
      • Programs
      • Research Networks
      • Type
    • Search
      • Simple
      • Advanced
    • About
      • About
      • Policies
      • Citation Guide
    • Login
      Login

      Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates

      Edit Item Edit Item

      General Information:

      Citation:
      Murray, S. , Diwan, H. , Orr, R. J. , Kohli, G. and John, U. (2015): Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates , MOLECULAR PHYLOGENETICS AND EVOLUTION, 92 , pp. 165-180 . doi: 10.1016/j.ympev.2015.06.017
      Cite this page as:
      hdl:10013/epic.46210
      DOI:
      https://doi.org/10.1016/j.ympev.2015.06.017
      Contact Email:
      Uwe.John@awi.de
      Related Data:

      Download:

      [img]
      Preview
      PDF
      murray.pdf

      Download (2MB) | Preview
      Cite this document as:
      hdl:10013/epic.46210.d001
      Abstract:

      A group of marine dinoflagellates (Alveolata, Eukaryota), consisting of similar to 10 species of the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense, produce the toxin saxitoxin and its analogues (STX), which can accumulate in shellfish, leading to ecosystem and human health impacts. The genes, sxt, putatively involved in STX biosynthesis, have recently been identified, however, the evolution of these genes within dinoflagellates is not clear. There are two reasons for this: uncertainty over the phylogeny of dinoflagellates; and that the sxt genes of many species of Alexandrium and other dinoflagellate genera are not known. Here, we determined the phylogeny of STX-producing and other dinoflagellates based on a concatenated eight-gene alignment. We determined the presence, diversity and phylogeny of sxtA, domains A1 and A4 and sxtG in 52 strains of Alexandrium, and a further 43 species of dinoflagellates and thirteen other alveolates. We confirmed the presence and high sequence conservation of sxtA, domain A4, in 40 strains (35 Alexandrium, 1 Pyrodinium, 4 Gymnodinium) of 8 species of STX-producing dinoflagellates, and absence from non-producing species. We found three paralogs of sxtA, domain A1, and a widespread distribution of sxtA1 in non-STX producing dinoflagellates, indicating duplication events in the evolution of this gene. One paralog, clade 2, of sxtA1 may be particularly related to STX biosynthesis. Similarly, sxtG appears to be generally restricted to STX-producing species, while three amidinotransferase gene paralogs were found in dinoflagellates. We investigated the role of positive (diversifying) selection following duplication in sxtA1 and sxtG, and found negative selection in clades of sxtG and sxtA1, clade 2, suggesting they were functionally constrained. Significant episodic diversifying selection was found in some strains in clade 3 of sxtA1, a clade that may not be involved in STX biosynthesis, indicating pressure for diversification of function. (C) 2015 Elsevier Inc. All rights reserved.

      Further Details:

      Item Type:
      Article
      Authors:
      Murray, S.A. ; Diwan, Hrutuja ; Orr, Russel. J.S. ; Kohli, Gurjeet ; John, Uwe
      Divisions:
      AWI Organizations > Biosciences > Ecological Chemistry
      Primary Division:
      Organizations > AWI Organizations > Biosciences > Ecological Chemistry
      Programs:
      Helmholtz Research Programs > PACES II (2014-2018) > TOPIC 2: Fragile coasts and shelf sea > WP 2.3: Evolution and adaptation to climate change and anthropogenic stress in coastal and shelf systems
      Primary Topic:
      Helmholtz Programs > Helmholtz Research Programs > PACES II (2014-2018) > TOPIC 2: Fragile coasts and shelf sea > WP 2.3: Evolution and adaptation to climate change and anthropogenic stress in coastal and shelf systems
      Eprint ID:
      38958
      Logo Alfred Wegener Institut
      Alfred-Wegener-Institut
      Helmholtz-Zentrum für Polar-
      und Meeresforschung
      Logo Helmholtz

      • Browse
        • Author
        • Year
        • Platform
        • Organizations
        • Programs
        • Research Networks
        • Type
      • Search
        • Simple
        • Advanced
      • About
        • About
        • Policies
        • Citation Guide
      • Imprint
      • Contact
      • OAI
      © Alfred-Wegener-Institut