High genetic load in an old isolated butterfly population

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    Sammanfattning

    We investigated inbreeding depression and genetic load in a small
    (Ne ∼ 100) population of the Glanville fritillary butterfly (Melitaea
    cinxia), which has been completely isolated on a small island
    [Pikku Tytärsaari (PT)] in the Baltic Sea for at least 75 y. As a reference,
    we studied conspecific populations from the well-studied
    metapopulation in the Åland Islands (ÅL), 400 km away. A large
    population in Saaremaa, Estonia, was used as a reference for estimating
    genetic diversity and Ne.We investigated 58 traits related
    to behavior, development, morphology, reproductive performance,
    and metabolism. The PT population exhibited high genetic
    load (L = 1 − WPT/WÅL) in a range of fitness-related traits including
    adult weight (L = 0.12), flight metabolic rate (L = 0.53), egg viability
    (L = 0.37), and lifetime production of eggs in an outdoor population
    cage (L = 0.70). These results imply extensive fixation of
    deleterious recessive mutations, supported by greatly reduced diversity
    in microsatellite markers and immediate recovery (heterosis)
    of egg viability and flight metabolic rate in crosses with other
    populations. There was no significant inbreeding depression in
    most traits due to one generation of full-sib mating. Resting metabolic
    rate was significantly elevated in PT males, which may be
    related to their short lifespan (L = 0.25). The demographic history
    and the effective size of the PT population place it in the part of
    the parameter space in which models predict mutation accumulation.
    This population exemplifies the increasingly common situation
    in fragmented landscapes, in which small and completely
    isolated populations are vulnerable to extinction due to high genetic
    load.
    Originalspråkengelska
    TidskriftProceedings of the National Academy of Sciences of the United States of America
    Volym109
    Utgåva37
    Sidor (från-till)E2496-2505
    Antal sidor10
    ISSN0027-8424
    DOI
    StatusPublicerad - 2012
    MoE-publikationstypA1 Tidskriftsartikel-refererad

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    • 1181 Ekologi, evolutionsbiologi

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