Figure 1.

Statistics Based on Distance Matrices and Empirical Variogram.

The Mantel correlation coefficient and R_V coefficient between the distance matrices D_X and D_Y from the geographic locations and the z-normalized metabolite profiles, respectively, of 20 Arabidopsis accessions. Approximations of the Euclidean distances due to Earth curvature are performed by converting the longitude and latitude from radial units to miles by multiplying the values with 53 and 69.1 mi. The Mantel correlation is calculated between the two distance matrices via the ecodist R package (Goslee and Urban, 2007), whereas the R_V coefficient for X and Y is determined via the FactoMineR package in R (Lê et al., 2008). The values are given in the inlay. The variogram is determined based on D_X and D_Y with four bins and eight bins, each covering a range of 50 and 25 mi, respectively. The mean γ for each bin is represented by a point. The size of the point corresponds to the number of pairs in the bin. Furthermore, the sd of each bin is represented by error bars. The empirical variograms are determined by a modified function of the geoR R package (Ribeiro and Diggle, 2001).