Figure 6From: 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 cis -regulatory element motifs in Populus trichocarpa . PCA based upon the abundance of cis-regulatory element motifs within promoter regions of NP-like genes in Populus trichocarpa. The percentage of variation explained by each axis is given in parentheses next along each axis.Back to article page