Severe inbreeding depression and no evidence of purging in an extremely inbred wild species - the Chatham Island Black Robin

Euan S. Kennedy, Catherine E. Grueber, Richard DUNCAN, Ian G. Jamieson

    Research output: Contribution to journalArticle

    25 Citations (Scopus)

    Abstract

    Although evidence of inbreeding depression in wild populations is well established, the impact of genetic purging in the wild remains controversial. The contrasting effects of inbreeding depression, fixation of deleterious alleles by genetic drift, and the purging of deleterious alleles via natural selection mean that predicting fitness outcomes in populations subjected to prolonged bottlenecks is not straightforward. We report results from a long-term pedigree study of arguably the world’s most inbred wild species of bird: the Chatham Island black robin Petroica traversi, in which conditions were ideal for purging to occur. Contrary to expectations, black robins showed a strong, negative relationship between inbreeding and juvenile survival, yielding lethal equivalents (2B) of 6.85. We also determined that the negative relationship between inbreeding and survival did not appear to be mediated by levels of ancestral inbreeding and may be attributed in part to unpurged lethal recessives. Although the black robin demographic history provided ideal conditions for genetic purging, our results show no clear evidence of purging in the major life-history trait of juvenile survival. Our results also show no evidence of fixation of deleterious alleles in juvenile survival, but do confirm that continued high levels of contemporary inbreeding in a historically inbred population could lead to additional severe inbreeding depression.
    Original languageEnglish
    Pages (from-to)987-995
    Number of pages9
    JournalEvolution: International Journal of Organic Evolution
    Volume68
    Issue number4
    DOIs
    Publication statusPublished - 2014

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    Songbirds
    inbreeding depression
    Inbreeding
    inbreeding
    Islands
    allele
    Alleles
    alleles
    lethal genes
    fixation
    Population
    Genetic Drift
    demographic history
    Genetic Selection
    genetic drift
    Pedigree
    wild population
    life history trait
    natural selection
    pedigree

    Cite this

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    abstract = "Although evidence of inbreeding depression in wild populations is well established, the impact of genetic purging in the wild remains controversial. The contrasting effects of inbreeding depression, fixation of deleterious alleles by genetic drift, and the purging of deleterious alleles via natural selection mean that predicting fitness outcomes in populations subjected to prolonged bottlenecks is not straightforward. We report results from a long-term pedigree study of arguably the world’s most inbred wild species of bird: the Chatham Island black robin Petroica traversi, in which conditions were ideal for purging to occur. Contrary to expectations, black robins showed a strong, negative relationship between inbreeding and juvenile survival, yielding lethal equivalents (2B) of 6.85. We also determined that the negative relationship between inbreeding and survival did not appear to be mediated by levels of ancestral inbreeding and may be attributed in part to unpurged lethal recessives. Although the black robin demographic history provided ideal conditions for genetic purging, our results show no clear evidence of purging in the major life-history trait of juvenile survival. Our results also show no evidence of fixation of deleterious alleles in juvenile survival, but do confirm that continued high levels of contemporary inbreeding in a historically inbred population could lead to additional severe inbreeding depression.",
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    Severe inbreeding depression and no evidence of purging in an extremely inbred wild species - the Chatham Island Black Robin. / Kennedy, Euan S.; Grueber, Catherine E.; DUNCAN, Richard; Jamieson, Ian G.

    In: Evolution: International Journal of Organic Evolution, Vol. 68, No. 4, 2014, p. 987-995.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Severe inbreeding depression and no evidence of purging in an extremely inbred wild species - the Chatham Island Black Robin

    AU - Kennedy, Euan S.

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    AU - Jamieson, Ian G.

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