CHROMOSOMAL LOCALIZATION OF HOMEOBOX GENES AND ASSOCIATED MARKERS ON PORCINE CHROMOSOME-3, CHROMOSOME-5, CHROMOSOME-12, CHROMOSOME-15, CHROMOSOME-16 AND CHROMOSOME-18 - COMPARATIVE MAPPING STUDY WITH HUMAN ANDMOUSE

Four homeobox genes that belong to the four homeobox gene clusters kno wn in mammals have been regionally assigned to four distinct porcine c hromosomes in conserved regions between human and pig. HOXA11, HOXB6, HOXC8, and HOXD4 genes were mapped by radioactive in situ hybridizatio n to porcine Chromosomes (Chrs) 18q21-24 (with a secondary signal in 1 6q14-21), 12p11-12, 5p11-12, and 15q22-23 respectively. Besides, we ha ve also revealed the presence of a porcine homeobox (pig Hbx24) which, although showing DNA sequence homology with a mouse gene of HOXB clus ter, was located on porcine Chr 3 (3p14-13) outside the Hox clusters. To support the identity of the homeobox gene clusters analyzed and in the light of the high sequence similarity among homeobox genes, we als o localized markers known to be mapped near each Hox cluster in human. In this way, four genes were also mapped in pig: GAPD (5412-21), GADI (15q21-22), INHBA (18q24). and IGFBP3 (18q24). Mapping of HOXA11, INH BA, and IGFBP3 on pig Chr 18 constitutes the first assignments of gene s on this small chromosome. These new localizations extend the informa tion on the conservation of four human chromosomal regions in the pig genome.