Fig. 3: Genetic clustering of M. guttatus populations across the Sierra Nevada.

(a) Principal Component Analysis (PCA) showing individual positions on PC1 and PC2. Individuals are coloured by their source population to match the geographic map shown in inset, (b) fastSTRUCTURE analysis with K = 2 reveals a north-south genetic divide, (c) the best supported fastSTRUCTURE model K = 6 shows geographic structure and population clustering. In b and c, individuals are represented by coloured bars, and assignment probability (Q-value) is displayed on the y‐axis.