Abstract
Understanding the persistence of genetic variation within populations has long been a goal of evolutionary biology. One promising route towards achieving this goal is using population genetic approaches to describe how selection acts on the loci associated with trait variation. In particular, gene expression provides a model trait for addressing the challenge of the maintenance of variation because it can be measured genome-wide without information about how gene expression affects traits. Previous work has shown that loci affecting the expression of nearby genes (cis-eQTL) tend to be under purifying selection, but we lack a clear understanding of the selective forces acting on variants that affect the expression of large numbers of genes across the genome (large-effect trans-eQTL). Here, we identify loci that affect the expression of coexpression networks using genomic and transcriptomic data from one population of the obligately outcrossing plant, Capsella grandiflora. We identify nine loci associated with the expression of 10s to 1000s of genes. One of these loci is also associated with trait variation, but we do not detect evidence of balancing selection acting on sequence variation surrounding these loci.








