Data from: Mating system and environmental variation drive patterns of adaptation in Boechera spatifolia (Brassicaceae)

Determining the relative contribution of population genetic processes to
the distribution of natural variation is a major goal of evolutionary
biology. Here, we take advantage of variation in mating system to test the
hypothesis that local adaptation is constrained by asexual reproduction.
We explored patterns of variation in ecological traits and genome-wide
molecular markers in Boechera spatifolia (Brassicaceae), a species that
contains both apomictic (asexual) and sexual individuals. Using a
combination of quantitative genetics, neutral genetic (SSR) and
genome-wide single nucleotide polymorphism, we assessed the hypothesis
that asexual lineages should have reduced signatures of adaptation
relative to sexual conspecifics. All three measures (traits, SSRs, SNPs)
demonstrated that apomicts are genetically distinct from sexuals,
regardless of population location. Additionally, phylogenetic clustering
revealed that the apomictic group shared a single common ancestor. Across
the landscape, sexual genome-wide SNP variation was strongly associated
with latitude (r2>0.9), indicating that sexual populations have
differentiated across an environmental gradient. Furthermore, flowering
time and growth rate, as assessed in a common garden, strongly covary with
the elevation and latitude of the source population. Despite a wide
geographic distribution that largely overlaps with sexual populations,
there was little evidence for differentiation in molecular markers or
quantitative characters among apomictic populations. Combined, these data
indicated that, in contrast to asexual populations, sexual populations
show evidence of local adaptation.