Figure 1.

The Eda haplotype contains three protein coding genes and 16 markers. The minimal region shared by most low‐plated, freshwater populations of threespine stickleback is 16‐kilobase long (gray bar). It contains the majority of three protein coding genes: Ectodysplasin (Eda), Tumor necrosis factor super‐family member 13b (Tnfsf13b), and Glycoprotein A rich protein (Garp). Genotyping assays were designed for 17 markers (triangles) that distinguish the marine or “C” allele (associated with the completely plated phenotype) and the freshwater or “L” allele (associated with the low‐plated phenotype). These markers are a mix of SNPs and indels indicated by gray and black triangles, respectively, and are listed in Table S1. Note: Exon 1 of Eda, and therefore SNP1, is outside the minimally shared freshwater haplotype.