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Within-population spatial genetic structure, neighbourhood size and clonal subrange in the seagrass Cymodocea nodosa.

Abstract

Abstract The extent of clonality within populations strongly influences their spatial genetic structure (SGS), yet this is hardly ever thoroughly analysed. We employed spatial autocorrelation analysis to study effects of sexual and clonal reproduction on dispersal of the dioecious seagrass Cymodocea nodosa. Analyses were performed both at genet level (i.e. excluding clonal repeats) and at ramet level. Clonal structure was characterized by the clonal subrange, a spatial measure of the linear limits where clonality still affects SGS. We show that the clonal subrange is equivalent to the distance where the probability of clonal identity approaches zero. This combined approach was applied to two meadows with different levels of disturbance, Cadiz (stable) and Alfacs (disturbed). Genotypic richness, the proportion of the sample representing distinct genotypes, was moderate (0.38 Cadiz, 0.46 Alfacs) mostly due to dominance of a few clones. Expected heterozygosities were comparable to those found in other clonal plants. SGS analyses at the genet level revealed extremely restricted gene dispersal in Cadiz (Sp = 0.052, a statistic reflecting the decrease of pairwise kinship with distance), the strongest SGS found for seagrass species, comparable only to values for selfing herbaceous land plants. At Cadiz the clonal subrange extended across shorter distances (20-25 m) than in Alfacs (30-35 m). Comparisons of sexual and vegetative components of gene dispersal suggest that, as a dispersal vector within meadows, clonal spread is at least as important as sexual reproduction. The restricted dispersal and SGS pattern in both meadows indicates that the species follows a repeated seedling recruitment strategy.

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  • Authors+Show Affiliations

    ,

    CCMAR, CIMAR-Laboratório Associado, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.

    , , , ,

    Source

    Molecular ecology 14:9 2005 Aug pg 2669-81

    MeSH

    Angiosperms
    Demography
    Genetics, Population
    Genotype
    Heterozygote
    Microsatellite Repeats
    Reproduction
    Seawater
    Spain

    Pub Type(s)

    Comparative Study
    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    16029469

    Citation

    TY - JOUR T1 - Within-population spatial genetic structure, neighbourhood size and clonal subrange in the seagrass Cymodocea nodosa. AU - Alberto,Filipe, AU - Gouveia,Licínia, AU - Arnaud-Haond,Sophie, AU - Pérez-Lloréns,José L, AU - Duarte,Carlos M, AU - Serrão,Ester A, PY - 2005/7/21/pubmed PY - 2005/9/22/medline PY - 2005/7/21/entrez SP - 2669 EP - 81 JF - Molecular ecology JO - Mol. Ecol. VL - 14 IS - 9 N2 - Abstract The extent of clonality within populations strongly influences their spatial genetic structure (SGS), yet this is hardly ever thoroughly analysed. We employed spatial autocorrelation analysis to study effects of sexual and clonal reproduction on dispersal of the dioecious seagrass Cymodocea nodosa. Analyses were performed both at genet level (i.e. excluding clonal repeats) and at ramet level. Clonal structure was characterized by the clonal subrange, a spatial measure of the linear limits where clonality still affects SGS. We show that the clonal subrange is equivalent to the distance where the probability of clonal identity approaches zero. This combined approach was applied to two meadows with different levels of disturbance, Cadiz (stable) and Alfacs (disturbed). Genotypic richness, the proportion of the sample representing distinct genotypes, was moderate (0.38 Cadiz, 0.46 Alfacs) mostly due to dominance of a few clones. Expected heterozygosities were comparable to those found in other clonal plants. SGS analyses at the genet level revealed extremely restricted gene dispersal in Cadiz (Sp = 0.052, a statistic reflecting the decrease of pairwise kinship with distance), the strongest SGS found for seagrass species, comparable only to values for selfing herbaceous land plants. At Cadiz the clonal subrange extended across shorter distances (20-25 m) than in Alfacs (30-35 m). Comparisons of sexual and vegetative components of gene dispersal suggest that, as a dispersal vector within meadows, clonal spread is at least as important as sexual reproduction. The restricted dispersal and SGS pattern in both meadows indicates that the species follows a repeated seedling recruitment strategy. SN - 0962-1083 UR - https://www.unboundmedicine.com/medline/citation/16029469/Within_population_spatial_genetic_structure_neighbourhood_size_and_clonal_subrange_in_the_seagrass_Cymodocea_nodosa_ L2 - http://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0962-1083&date=2005&volume=14&issue=9&spage=2669 ER -