Hox genes and pattern formation in the branchial region of the vertebrate head.

The conservation of molecular mechanisms in evolution has stimulated interest in comparative embryology, and the Hox/HOM-C homeobox complexes are among the best examples of the remarkable conservation between species. An important region associated with Hox patterning is the head, where the evolutionary and molecular studies have reawakened interest in the cellular processes and complex interactions required to regulate craniofacial morphogenesis.