Figure 6. Signals of selection in UCSD juncos.Redundancy analysis (RDA) between 132,343 SNP response variables and four explanatory variables corresponding to environmental factors (mean temperature of the warmest quarter, temperature seasonality, greenness, and elevation) for Oregon junco forms. Points represent the projection of individual genotypes on the first two RDA axes. Marker colors correspond to those on the range map in Fig. 1. The explanatory variables are shown within the space defined by RDA1 and RDA2 by labeled vectors, and their contribution to each axis is represented by the length of their orthogonal projections over the scale bars along the x and y axes. Vector arrows indicate the direction of the gradient of variation for the corresponding environmental parameter. The loading score of each sample point on each explanatory variable can be obtained by an orthogonal projection on the corresponding plotted vector.