Functional analysis of module 4. (A) Significantly over-represented GO terms detected in module 4. (B) Co-expression patterns of 280 module genes over the 237 arrays which made up a gene expression map of Arabidopsis development . In the heat map, each row represents a gene, and each column represents an array. Prior to hierarchical clustering, a gene's expression values over the 237 arrays were processed so that they had a zero mean and unit standard deviation. Arrays sampled from the same tissue were grouped together. 'a+l' represents the tissue that includes both shoot apex (vegetative) and young leaves. The heat map was generated using dChip software . (C) A closer examination of the expression pattern of 280 module genes in different floral organs and whole flower tissues at different development stages. To generate the heat map, genes' expression values were extracted from the 280 × 237 data matrix, which were used to produce the heat map depicted in (B). Stage_XX represents a flower development stage, 'stam' represents stamen, 'carp' represents carpel, 'pedi' represents pedicel. For each experimental condition (e.g. stage_12_sepal), three replicates were measured.