Gene expression profiles during 16 days of EB differentiation in serum and serum-free media containing BMP4 [2 ng/ml]. (A) GeneSpring representation of the subset of genes from the 48 K Illumina array that showed significant differences in gene expression at 2 or more time points. Each line represents the mean normalised expression of an individual Illumina probe. Colours represent relative expression (red 4× increased; green 0.25× reduced) compared to a gene mean of 1 (black) with expression in undifferentiated ES cells (day 0) as the decision point for colour coding. The expression profiles of T (brachyury), Hba (α-globin), and Igf2 are indicated for reference. (B) Clustering (tree) of the genes that showed significant (p < 0.01) changes in gene expression upon differentiation by One-way Welch ANOVA. Expression levels are heat map colour coded (inset) with high expression at Day 0 coloured red and low expression coloured green.