The authors developed a method for carrying out genome-wide association studies in polyploid plants that is applicable to species with no genomic resources. Their rationale is to make use of the SNP and gene expression variation data available in RNA sequencing (RNA-seq) data sets. These data are mapped onto a genomic architecture assembled by SNP linkage mapping and using data from related species, and the variants are then correlated with traits. They applied this method to a panel of 84 Brassica napus accessions and identified quantitative trait loci for glucosolinate content of seeds.