Identification and genetic mapping of a homeobox gene to the 4p16.1 region of human chromosome 4

A human craniofacial cDNA library was screened with a degenerate oligonucleotide probe based on the conserved third helix of homeobox genes. From this screening, we identified a homeobox gene, H6, which shared only 57-65% amino acid identity to previously reported homeodomains. H6 was physically mapped to the 4p16.1 region by using somatic cell hybrids containing specific deletions of human chromosome 4. Linkage data from a single-stranded conformational polymorphism derived from the 3′ untranslated region of the H6 cDNA placed this homeobox gene more than 20 centimorgans proximal of the previously mapped HOX7 gene on chromosome 4. Identity comparisons of the H6 homeodomain with previously reported homeodomains reveal the highest identities to be with the Nk class of homeobox genes in Drosophila melanogaster.