Fig. 3: Pairwise genetic differentiation between clinal sites along a representative chromosome.

Genetic differentiation is expressed as absolute allele frequency differentiation (AFD) for four site comparisons, each involving the lake site L1. The colored lines represent differentiation smoothed across SNPs by non-parametric regression. For the comparison between the endpoint samples (L1-S7), differentiation is additionally shown for all SNPs individually (gray dots). Note that the differentiation profile from the L1-S1 comparison resembles the within-lake (L1-L2) comparison, except for a few genome regions particularly strongly differentiated in the L1-S1 comparison. The latter also prove exceptionally strongly differentiated between the lake and the more distant stream sites.