Heat map of CYP developmental expression with each gene z-normalized to display the temporal expression waves. Hierarchical K-means clustering of z-normalized data exposes the temporal waves of CYP gene expression through early zebrafish development. Different clusters of genes are expressed at the different sampling times. A few sets of genes exhibit bimodal distributions, particularly CYP3A65, 8B1, 2N13, 2K22, and to a lesser extent, CYP21A1, 2K17, 8B3, 27A4, and 5A1. Unnormalized clustering presents a different pattern, as high-expressing genes tend to be clustered together (Additional File 1, Figure S6). CYP2AA6, CYP2AA13, CYP2P8, CYP2X6, CYP2X9, and CYP46A5 are not represented on the microarray, as the microarray was generated using Zv6 rather than the current genome assembly.