Hierarchical clustering of G protein-coupled receptors differentially expressed during the development of cerebellar granule neuroblasts in vitro. Transcripts encoding 382 GPCRs were quantified using real-time PCR throughout the developmental process that leads from cerebellar granule neuroblasts to mature neurons in vitro. Data represent the average of 3 independent reverse transcription and PCR experiments. To take into account technical variations, the level of expression of each GPCR was normalized to the geometric mean of the expression levels of 3 selected reference genes, i.e. B2m, Gapdh, and Gusb. A Kruskal-Wallis test with Benjamini-Hochberg correction identified those GPCRs differentially expressed (DE) at one time point at least. Each GPCR was then expressed as the percentage of the maximal expression levels of that GPCR during the time course. DE GPCRs were classified according to their expression pattern using a hierarchical clustering algorithm as implemented in MeV 4.2.