The hypotrophic axonopathy mutant in Japanese quail

A new behavioral mutant showing either head or body quivering, or both, was found in Japanese quail. This trait was characterized by neurofilament deficiency in the axons of the cervical spinal cord and the optic and sciatic nerves and was named "hypotrophic axonopathy." This character was shown to be controlled by an autosomal recessive gene, for which the gene symbol hax was proposed.