Two colonisation stages generate two different patterns of genetic diversity within
native and invasive ranges of Ulex europaeus |
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Authors: | B Hornoy A Atlan V Roussel Y M Buckley M Tarayre |
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Institution: | 1.Ecobio, Centre National de la Recherche
Scientifique—Université de Rennes 1, Rennes, France;2.ARC Centre of Excellence for Environmental
Decision, The University of Queensland, School of Biological Sciences, Queensland, Australia |
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Abstract: | Genetic diversity and the way a species is introduced influence the capacity of
populations of invasive species to persist in, and adapt to, their new environment. The
diversity of introduced populations affects their evolutionary potential, which is
particularly important for species that have invaded a wide range of habitats and
climates, such as European gorse, Ulex europaeus. This species originated in the
Iberian peninsula and colonised Europe in the Neolithic; over the course of the past two
centuries it was introduced to, and has become invasive in, other continents. We
characterised neutral genetic diversity and its structure in the native range and in
invaded regions. By coupling these results with historical data, we have identified the
way in which gorse populations were introduced and the consequences of introduction
history on genetic diversity. Our study is based on the genotyping of individuals from 18
populations at six microsatellite loci. As U. europaeus is an allohexaploid
species, we used recently developed tools that take into account genotypic ambiguity. Our
results show that genetic diversity in gorse is very high and mainly contained within
populations. We confirm that colonisation occurred in two stages. During the first stage,
gorse spread out naturally from Spain towards northern Europe, losing some genetic
diversity. During the second stage, gorse was introduced by humans into different regions
of the world, from northern Europe. These introductions resulted in the loss of rare
alleles but did not significantly reduce genetic diversity and thus the evolutionary
potential of this invasive species. |
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Keywords: | Colonisation invasive species polyploidy population genetic structure |
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