highly significantp < 1 × 10 −15
While there is a highly significant correlation between PC1 for both methods ( R 2 = 0.949, p < 1 × 10 −15 ), later PCs are often not significantly correlated, with the most notable exception being EFD PC2 and PH PC3 ( R 2 = 0.432, p < 1 × 10 −15 ), although several other PCs also show weak correlations.