Figure 1. A) Map of C. anna samples grouped by region with native (triangle) or expanded (circle) range indicated by shape. The regions are defined as follows: Washington state (WAS), Humboldt County (HUM), San Francisco Bay Area (BAY), California Central Valley (VAL), Pacific Coast (PAC), and the eastern expanded region (EAS). B) Genetic divergence (weighted FST) showing little relationship with increasing pairwise county geographic distance (y = 0.004 – 8.6E-10x )C) Hierarchical clustering analysis for 2 (K=2) ancestral groups, which was found to be the optimal number of groups. For additional ancestral groups (K=3–5) see Fig. S3. D) The second and third components from the principal component analysis (PCA) in which samples are colored by region (see A) and the shapes indicate if the samples are from the native (circle) or expanded (triangle) ranges. The first axis appeared to be driven by sequencing pool (see Fig. S4A).