Figure S1. Interpolated candidate gene distribution map for the candidate SNP Etr_1806 on chromosome 04. Allele proportions are color coded from low to high proportions of the A allele for Etr_1806 which was associated with large adult body size in the Columbia River. Despite relatively high numbers of large adults in the Klamath River, the alternative allele G was found in higher frequencies in California, which made association with body size inconsistent for this locus and could indicate an unmeasured trait is the true target of selection.