Abdominal B-type Hox gene expression in Xenopus laevis.

We have studied the expression of the Abdominal B-type Hox genes in Xenopus embryos and tadpoles. The probes used represent all paralog groups and are designated Xhoxa9, Xhoxd9, Xhoxd10, Xhoxa11, Xhoxc12 and Xhoxa13 on the basis of comparison to other vertebrates. Three of these genes are novel while the others have previously been detected but expression patterns were only partially described. We find a typical nested pattern of expression in the main body axis, in both central nervous system and mesoderm. All the genes, except Xhoxc12, are also expressed in the mesenchyme of the large intestine and in the limb buds.