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Gene, phenotype and function: GLABROUS1 and resistance to herbivory in natural populations of Arabidopsis lyrata

Authors

  • MAARIT KIVIMÄKI,

    1. Finnish Forest Research Institute, Vantaa Research Unit, PO Box 18, 01301 Vantaa, Finland,
    2. Population Genetics Graduate School, Department of Biology, University of Oulu, Finland,
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  • KATRI KÄRKKÄINEN,

    1. Finnish Forest Research Institute, Vantaa Research Unit, PO Box 18, 01301 Vantaa, Finland,
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  • MYRIAM GAUDEUL,

    1. Department of Plant Ecology, Evolutionary Biology Centre, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden,
    2. Département Systématique et Evolution, Museum National d’Histoire Naturelle, 16 Rue Buffon, F-75005 Paris, France
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  • GEIR LØE,

    1. Department of Plant Ecology, Evolutionary Biology Centre, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden,
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  • JON ÅGREN

    1. Department of Plant Ecology, Evolutionary Biology Centre, Uppsala University, Villavägen 14, SE-752 36 Uppsala, Sweden,
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Maarit Kivimäki, Fax: +358-10-2112206; E-mail: maarit.kivimaki@metla.fi

Abstract

The molecular genetic basis of adaptive variation is of fundamental importance for evolutionary dynamics, but is still poorly known. Only in very few cases has the relationship between genetic variation at the molecular level, phenotype and function been established in natural populations. We examined the functional significance and genetic basis of a polymorphism in production of leaf hairs, trichomes, in the perennial herb Arabidopsis lyrata. Earlier studies suggested that trichome production is subject to divergent selection. Here we show that the production of trichomes is correlated with reduced damage from insect herbivores in natural populations, and using statistical methods developed for medical genetics we document an association between loss of trichome production and mutations in the regulatory gene GLABROUS1. Sequence data suggest that independent mutations in this regulatory gene have provided the basis for parallel evolution of reduced resistance to insect herbivores in different populations of A. lyrata and in the closely related Arabidopsis thaliana. The results show that candidate genes identified in model organisms provide a valuable starting point for analysis of the genetic basis of phenotypic variation in natural populations.

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