Fig. 2

RAD-seq cluster distribution against a measurement of population divergence for yellow-billed pintail (top) and speckled teal (bottom): histogram is distribution of all SNP variants (RAD-seq, and HIF pathway genes), with specific genes of interest highlighted: EGLN1 (blue) and EPAS1 (orange), whereas markers with black arrows signify the nonsynonymous/synonymous amino-acid variants in exonic regions of EGLN1 and EPAS1