PCA of the grouped cell-cycle data. Biplot of gene scores and cell-cycle phase group loadings according to the first two components of the PCA. The open circles or gene names represent the gene scores. The vectors represent the cell-cycle phase group (variable) loadings. The biplot enables the association of genes with the cell-cycle phase groups. Labeled genes were selected by permutation test.
Landgrebe et al. Genome Biology 2002 3:research0019.1-research0019.11 doi:10.1186/gb-2002-3-4-research0019