A rational nomenclature for vertebrate homeobox (HOX) genes.

Developmental fates along the anterior-posterior axes of animals are controlled by clustered homeotic genes which in vertebrates are called Hox genes. The gene clusters are similar and probably functionally homologous in animals as different as nematodes, flies, and mammals. A new set of names for Hox genes was recently agreed upon by many workers in the field. Remarkably, the order of the Hox genes along the chromosome reflects where they are expressed along the body axis. This simple principle is reflected in the new nomenclature system.