Cdx and Hox genes differentially regulate posterior axial growth in mammalian embryos.SOX9 is an intestine crypt transcription factor, is regulated by the Wnt pathway, and represses the CDX2 and MUC2 genesWnt/beta-catenin signaling regulates the expression of the homeobox gene Cdx1 in embryonic intestineCdx2 determines the fate of postnatal intestinal endoderm