Population structure. Principal Component Analysis representing individual structuring across Lake Constance populations. Analysis was performed on pruned data excluding the sex chromosome (11,184 SNPs). Colours indicate different sampling sites, while shapes represent habitats – inflow (circle), littoral (square), pelagic (triangle). Smaller, lighter data points show individual variation, while the larger shapes with a black centre indicate population Principal Component centroids, which were calculated as the mean of both the 1st and 2nd axes.