Figure 4From: Elucidating the evolutionary history and expression patterns of nucleoside phosphorylase paralogs (vegetative storage proteins) in Populusand the plant kingdomPrincipal component analysis (PCA) of NP-like gene expression in Populus trichocarpa . PCA illustrating the relationships of NP-like genes in Populus trichocarpa based upon the expression data presented in Figure 1B. The percentage of variation explained by each axis is given in parentheses next along each axis.Back to article page