Fig. 4: Ancestral populations from TESS3R.

a Cross-validation score from TESS3r plotted against number of ancestral populations (K) of common toads in Scandinavia. Cross-validation is performed through calculating root mean-squared errors for a subset of loci. The best K is found where the cross-validation score starts to plateau. b Cluster analysis bar plot for values of K between 2 and 6, implemented through TESS3r. Populations of common toads are grouped by region and are ordered by increasing latitude, each bar is one individual.