The mouse cerebellar cortex is an ideal structure for studies of molecular and genetic networks controlling morphogenesis in the CNS. The cerebellum has simple anatomy and a defined set of steps for establishing its structure, and develops postnatally. Our previous study (Morrison, et al., SFN Abstract, 2003) used Affymetrix gnGNF1Musa chips to generate a full genome scale microarray dataset, which represents the gene expression levels of mouse whole cerebellum on postnatal day 0, 4, 8, 12, 16, 20, or 30. Here we employed advanced bioinformatic approach to further profile the temporal gene expression. Principle component analysis revealed 8 major expression patterns. The 1st component representing the genes with continuously increased or decreased levels counts for half (49.2%) of the total variation. The 2nd component showing a highest or lowest expression at the middle age (P8 & P12) contributes 20.2% to the total variation. The 3rd component (17.7%) has a peak/volley at the P4 & P8, while the 4th (12.9%...