Vertebrate aristaless-related genes.

Aristaless-related genes, a subset of the Paired-related homeobox genes, have in the past few years emerged as a group of regulators of essential events during vertebrate embryogenesis. One group of aristaless-related genes has been linked to the morphogenesis of the craniofacial and appendicular skeleton by their expression patterns and by the phenotypes of natural and artificial mouse mutants. Expression and function in the nervous system characterise a second group, and a third group, the Pitx genes, have been shown to have many different roles, including functions in the pituitary, left-right determination and limb development.