Fig. 4

Population genetic structure within triads. STRUCTURE plots for Oyster Creek (a) and Brayton Point (b) triads based on data from the most differentiated loci (all pairwise outliers within a triad). Each individual is represented with a radial line that is partitioned into colors according to modeled admixture proportions for k ancestral populations. Results for k = 2–4 are presented with best k denoted by an asterisk. DAPC plots for Oyster Creek (c) and Brayton Point (d) triads using the full SNP dataset. Each individual’s position along the first two principal components (discriminant functions) is shown with a point, with populations identified by color. The relative eigenvalues of the first (horizontal) and second (vertical) principal components are shown in the bar plot at the bottom right of each figure