Data from: Paths to selection on life history loci in different natural environments across the native range of Arabidopsis thaliana

Selection on quantitative trait loci (QTL) may vary among natural
environments due to differences in the genetic architecture of traits,
environment-specific allelic effects or changes in the direction and
magnitude of selection on specific traits. To dissect the environmental
differences in selection on life history QTL across climatic regions, we
grew a panel of interconnected recombinant inbred lines (RILs) of
Arabidopsis thaliana in four field sites across its native European range.
For each environment, we mapped QTL for growth, reproductive timing and
development. Several QTL were pleiotropic across environments, three
colocalizing with known functional polymorphisms in flowering time genes
(CRY2, FRI and MAF2-5), but major QTL differed across field sites, showing
conditional neutrality. We used structural equation models to trace
selection paths from QTL to lifetime fitness in each environment. Only
three QTL directly affected fruit number, measuring fitness. Most QTL had
an indirect effect on fitness through their effect on bolting time or leaf
length. Influence of life history traits on fitness differed dramatically
across sites, resulting in different patterns of selection on reproductive
timing and underlying QTL. In two oceanic field sites with high
prereproductive mortality, QTL alleles contributing to early reproduction
resulted in greater fruit production, conferring selective advantage,
whereas alleles contributing to later reproduction resulted in larger size
and higher fitness in a continental site. This demonstrates how
environmental variation leads to change in both QTL effect sizes and
direction of selection on traits, justifying the persistence of allelic
polymorphism at life history QTL across the species range.