Data from: Role of seed germination in adaptation and reproductive isolation in Arabidopsis lyrata

Seed germination is an important developmental and life history stage.
Yet, the evolutionary impact of germination has mainly been studied in the
context of dormancy, or for its role in reproductive isolation between
species. Here, we aim to examine multiple consequences of genetic
divergence on germination traits between two Arabidopsis lyrata
subspecies: ssp. petraea (Eurasia) and ssp. lyrata (North-America).
Post-dormancy germination time, a potentially adaptive trait, showed
differentiation between the populations, and quantitative trait loci (QTL)
mapping revealed that the trait variation is mainly controlled by two
antagonistic loci. These QTL areas contain several candidate genes with
known function in post-dormancy germination in A. thaliana. The sequence
variation of three genes was consistent with differential selection, and
they also included fixed nonsynonymous substitutions with potential to
account for the phenotypic differentiation. We further show that the
divergence between the subspecies has led to a slight but significant
reduction in hybrid germination proportions, indicating incipient
reproductive isolation. Comparison of reciprocal F1 and F2 progenies
suggest that Bateson-Dobzhansky-Muller-incompatibilities likely act
through uniparentally inherited factors. Examination of genome-wide
transmission ratio distortion further revealed that cytonuclear
interactions cause substantial pregermination inviability in the hybrids.
These results confirm that seed germination has adaptive potential beyond
the dormancy stage and that hybrid seed inviability can be one of the
first reproductive barriers to arise during divergence.