Data from: Two colonisation stages generate two different patterns of genetic diversity within native and invasive ranges of Ulex europaeus

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 last 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 Ulex europaeus is an
allohexaploid species, we used recently developed tools which 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.