A bacterial artificial chromosome (BAC; no. 16652; Genome Systems, St. Louis, Mo.) containing the mouse Myoc gene and flanking genomic sequence was used to generate transgenic mice. The mouse strain used to generate the BAC was a 129-derived strain and has a repeat length polymorphism compared to C57BL/6J that is located approximately 4 kb upstream from the start codon. (J:93323)