GENETIC POPULATION STRUCTURE AND MATING SYSTEM IN CHONDRUS CRISPUS (RHODOPHYTA)

Authors

  • Stacy A. Krueger-Hadfield,

    1. UPMC Univ Paris 06, UMR7144, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Place Georges Teissier, 29682 Roscoff, France CNRS, UMR7144, Station Biologique de Roscoff, France Department of Biology, California State University Northridge, 18111 Nordhoff St., Northridge, California 91330-8303, USA
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  • Jonas Collén,

    1. UPMC Univ Paris 06, UMR7139, Végétaux Marins et Biomolécules, Station Biologique de Roscoff, Place Georges Teissier, 29682 Roscoff, France
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  • Claire Daguin-Thiébaut,

    1. UPMC Univ Paris 06, UMR7144, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Place Georges Teissier, 29682 Roscoff, France CNRS, UMR7144, Station Biologique de Roscoff, France
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  • Myriam Valero

    1. UPMC Univ Paris 06, UMR7144, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Place Georges Teissier, 29682 Roscoff, France CNRS, UMR7144, Station Biologique de Roscoff, France
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  • Received 25 June 2010. Accepted 22 October 2010.

Abstract

Chondrus crispus Stackh. has been intensely studied, yet no study to date has elucidated its population structure or mating system despite many populations in which there was a haploid bias and lack of male gametophytes. Therefore, 12 nuclear microsatellite loci were identified in this red alga. Microsatellite markers were developed and tested against a panel of specimens collected from two shore levels at two sites in Brittany, France: Pointe de Primel and Pointe de la Jument, Concarneau. Single locus genetic determinism was verified at eight polymorphic loci, as only one band was observed for haploid genotypes, whereas one or two bands were observed for diploids. These markers enabled the detection of unique genotypes within sampled populations, indicating that very few fronds shared the same multilocus genotype. This finding suggests that asexual reproduction was not the prevailing mode of reproduction. In addition, we explored the hierarchical population structure showing that gene flow is restricted at small spatial scales (<50 m) between upper and lower Chondrus-range populations within a shore. Sexual reproduction predominated in the populations of C. crispus studied, but probably due to fine-scale spatial substructuring, inbreeding was also significant. In conclusion, this study reveals that fine-scale genetic variation is of major importance in C. crispus, suggesting that differences between microhabitats should be essential in understanding evolutionary processes in this species.

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