Pax1, a member of the paired box-containing class of developmental control genes, is mapped to human chromosome 20p11.2 by in situ hybridization (ISH and FISH).

Pax-1, a member of a murine multigene family, belongs to the paired box-containing class of developmental control genes first identified in Drosophila. The Pax-1 gene encodes a sequence-specific DNA-binding protein with transcriptional activating properties and has been found to be mutated in the autosomal recessive mutation undulated (un) on mouse chromosome 2 with vertebral anomalies along the entire rostrocaudal axis. By radioactive in situ hybridization (ISH) using a fragment from the murine Pax-1 paired box that is almost identical to the respective sequences from the cognate human gene HuP48 and fluorescence in situ hybridization (FISH) using a complete mouse Pax-1 cDNA, we have assigned the human homologue of murine Pax-1, the PAX1 locus, to chromosome 20p. The map position of PAX1 after FISH (FL-pter value of 0.34 +/- 0.04) corresponds to band p11.2. These results confirm the exceptional homology between human chromosome 20 and the distal segment of mouse chromosome 2, extending from bands F to G, and add PAX1 to the group of genes on 20p like PTPA, PRNP, SCG1, BMP2A, which are located in proximity on both chromosomes.