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From homothally to heterothally; mating preferences and genetic variation within clones of the dinoflagellate Gymnodinium catenatum

Author:
  • Rosa Figueroa
  • Karin Rengefors
  • Isabel Bravo
  • Staffan Bensch
Publishing year: 2010
Language: English
Pages: 190-198
Publication/Series: Deep-Sea Research. Part Ii, Topical Studies in Oceanography
Volume: 57
Issue: 3-4
Document type: Journal article
Publisher: Elsevier

Abstract english

The chain-forming dinoflagellate Gymnodinium catenatum Graham is responsible for outbreaks of paralytic shellfish poisoning (PSP), a human health threat in coastal waters. Sexuality in this species is of great importance in its bloom dynamics, and has been shown to be very complex but lacks an explanation. For this reason, we tested if unreported homothallic behavior and rapid genetic changes may clarify the sexual system of this alga. To achieve this objective, 12 clonal strains collected from the Spanish coast were analyzed for the presence of sexual reproduction. Mating affinity results, self-compatibility studies, and genetic fingerprinting (amplified fragment length polymorphism, AFLP) analysis on clonal strains, showed three facts not previously described for this species: (i) That there is a continuous mating system within G. catenatum, with either self-compatible strains (homothallic), or strains that needed to be outcrossed (heterothallic), and with a range of differences in cyst production among the crosses. (ii) There was intraclonal genetic variation, i.e. genetic variation within an asexual lineage. Moreover, the variability among homothallic clones was smaller than among the heterothallic ones. (iii) Sibling strains (the two strains established by the germination of one cyst) increased their intra- and inter-sexual compatibility with time. To summarize, we have found that G. catenatum's sexual system is much more complex than previously described, including complex homothallic/heterothallic behaviors. Additionally, high rates of genetic variability may arise in clonal strains, although explanations for the mechanisms responsible are still lacking. (C) 2009 Elsevier Ltd. All rights reserved.

Keywords

  • Ecology
  • Biological Sciences
  • Gymnodinium catenatum
  • AFLPs
  • Sexual
  • compatibility
  • Life cycle
  • Intraclonal genetic variation
  • Mating
  • Dinophyceae
  • Encystment

Other

Published
  • Molecular Ecology and Evolution Lab
  • ISSN: 0967-0645
Staffan Bensch
E-mail: staffan [dot] bensch [at] biol [dot] lu [dot] se

Professor

MEMEG

+46 46 222 42 92

E-C213

Sölvegatan 37, Lund

50

Head of unit

MEMEG

+46 46 222 42 92

E-C213

Sölvegatan 37, Lund

50

Research group

Molecular Ecology and Evolution Lab

Projects

Doctoral students and postdocs

PhD students, main supervisor

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