Data from: Morphological and genetic discrepancies in populations of Oreocarya paradoxa and O. revealii: the impact of edaphic selection on recent diversification in the Colorado Plateau

PREMISE OF THE STUDY: Investigations of recently derived and edaphically
(soil) defined plant systems have provided insight into important
mechanisms of ecological divergence. We investigated the impact of edaphic
adaptation on recent divergence between two Colorado Plateau endemics: the
gypsum facultative Oreocarya revealii (Boraginaceae) and its more
generalist sister species O. paradoxa. We assessed morphological
stability, genetic identity, and soil chemistry to determine whether O.
revealii is a distinct lineage edaphically adapted from O. paradoxa, as
has been described in the literature. METHODS: We genotyped 21 populations
throughout the ranges of both species using 11 microsatellite markers and
three plastid regions (trnL-F, trnT-L, trnQ-rps16) for haplotype analysis.
We compared these data with soil chemistry (Ca and S concentrations,
indicating gypsum levels), location, and morphological identity of
populations. KEY RESULTS: Soil chemistry failed to explain genetic or
morphological identity in either taxon. Haplotype analysis suggests
ancestral variation in the more geographically restricted O. revealii,
along with regional geographic isolation. A discontinuity was identified
between the morphological and genetic identity in several populations,
suggesting incomplete lineage sorting and the nonfixation of identifying
morphological traits. CONCLUSIONS: Oreocarya revealii is unlikely to have
arisen via edaphic selection, because soil chemistry of population sites,
morphology of individuals, and genetic identity are not strongly
correlated. The nonfixation of identifying traits is likely a result of
recent divergence in this system, and the potentiality of such
discrepancies should be considered when investigating recently diversified
gypsum-associated groups.