Data from: The genetic basis of traits associated with the evolution of serpentine endemism in monkeyflowers

The floras on chemically and physically challenging soils, such as gypsum,
shale, and serpentine, are characterized by narrowly endemic species. The
evolution of edaphic endemics may be facilitated or constrained by genetic
correlations among traits contributing to adaptation and reproductive
isolation across soil boundaries. The yellow monkeyflowers in the Mimulus
guttatus species complex are an ideal system in which to examine these
evolutionary patterns. To determine the genetic basis of adaptive and
prezygotic isolating traits, we performed genetic mapping experiments with
F2 hybrids derived from a cross between a serpentine endemic, M. nudatus,
and its close relative M. guttatus. Few large effect and many small effect
QTL contribute to interspecific divergence in life history, floral and
leaf traits, and a history of directional selection contributed to trait
divergence. Loci contributing to adaptive traits and prezygotic
reproductive isolation overlap, and their allelic effects are largely in
the direction of species divergence. These loci contain promising
candidate genes regulating flowering time and plant organ size. Together
our results suggest that genetic correlations among traits can facilitate
the evolution of adaptation and speciation and may be a common feature of
the genetic architecture of divergence between edaphic endemics and their
widespread relatives.