Cdx gene induction modulates Hox gene expression in differentiating EBs. Quantitative real-time RT-PCR analysis of the effect of ectopic Cdx1, Cdx4, and Cdx2 gene induction on Hox A and B cluster genes in day 5 EBs. The data represent the average of 2 independent experiments and are presented as fold change relative to noninduction controls. Error bars represent the standard error. P values calculated using nonpaired, 2-tailed Student t test are depicted over bars.