A selective sweep in a microsporidian parasite Nosema-tolerant honeybee population, Apis mellifera

Authors

  • Q. Huang,

    Corresponding author
    1. Institut für Biologie/Zoologie, Molekulare Ökologie, Martin-Luther-Universität Halle -Wittenberg, Halle (Saale), Germany
    2. Honeybee Research Institute, Jiangxi Agricultural University, Nanchang, China
    • Address for correspondence

      Q. Huang, Institut für Biologie/Zoologie, Molekulare Ökologie, Martin-Luther-Universität Halle -Wittenberg, Hoher Weg 4, 06099 Halle (Saale), Germany.

      E-mail: qiang.huang@zoologie.uni-halle.de

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  • H. M. G. Lattorff,

    1. Institut für Biologie/Zoologie, Molekulare Ökologie, Martin-Luther-Universität Halle -Wittenberg, Halle (Saale), Germany
    2. German Institute for Integrative Biodiversity Research (iDiv), Leipzig, Germany
    Current affiliation:
    1. Institut für Biologie, Tierphysiologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
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  • P. Kryger,

    1. Department of Agroecology, Section of Entomology and Plantpathology, Aarhus University, Slagelse, Denmark
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  • Y. Le Conte,

    1. INRA, UMR 406 Ecologie des Invertébrés, Avignon Cedex 9, France
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  • R. F. A. Moritz

    1. Institut für Biologie/Zoologie, Molekulare Ökologie, Martin-Luther-Universität Halle -Wittenberg, Halle (Saale), Germany
    2. German Institute for Integrative Biodiversity Research (iDiv), Leipzig, Germany
    3. RoBeeTech, Universitatea de Stiinte Agricole si Medicina Vetereinaria Cluj-Napoca, Cluj-Napoca, Romania
    4. Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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Summary

Nosema is a microsporidian parasite of the honeybee, which infects the epithelial cells of the gut. In Denmark, honeybee colonies have been selectively bred for the absence of Nosema over decades, resulting in a breeding line that is tolerant toward Nosema infections. As the tolerance toward the Nosema infection is a result of artificial selection, we screened chromosome 14 for a selective sweep with microsatellite markers, where a major quantitative trait locus (QTL) had been identified to be involved in the reduction in Nosema spores in the honeybees. By comparing the genetic variability of 10 colonies of the selected honeybee strain with a population sample from 22 unselected colonies, a selective sweep was revealed within the previously identified QTL region. The genetic variability of the swept loci was not only reduced in relation to the flanking markers on chromosome 14 within the selected strain but also significantly reduced compared with the same region in the unselected honeybees. This confirmed the results of the previous QTL mapping for reduced Nosema infections. The success of the selective breeding may have driven the selective sweep found in our study.

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