A mouse homeo box gene, Hox-1.5, and the morphological locus, Hd, map to within 1 cM on chromosome 6.

Mo-10, a homeo box-containing sequence in the Hox-1 complex of genes referred to as Hox-1.5, was found to be polymorphic in inbred and wild mice, and a strain distribution of three allelic forms of Hox-1.5 are reported. The position of Hox-1.5 was mapped in backcross experiments to within 1 cM of the hypodactyly locus on chromosome 6. This identifies the Hd mutation as a useful model for the examination of homeo box expression during mammalian development.