the locations of these genes and the evolutionary distance between their sequences suggest that at least three distinct genetic events have occurred during the evolution of the aromatic amino acid hydroxylase superfamily : two sequential gene duplications giving rise to the three distinct hydroxylase loci , and a translocation which separated the tryptophan and tyrosine hydroxylase loci on chromosome 11 from the phenylalanine hydroxylase locus on chromosome 12 .
C0020364
hydroxylase
C0031456
phenylalanine hydroxylase