A DETAILED PHYSICAL MAP OF THE PORCINE MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) CLASS-III REGION - COMPARISON WITH HUMAN AND MOUSE MHC CLASS-III REGIONS

A detailed physical map of the porcine MHC class III region on Chr 7 w as constructed with a panel of probes in a series of hybridizations on genomic pulsed field gel electrophoresis (PFGE) Southern blots. A pre cise organization of the 700-kb seg ment of DNA between G18 and BAT1 c an now be proposed, with more than 30 genes mapped to it. Comparison o f this region with homologous regions in human and mouse showed only m inor differences. The biggest difference was observed in the CYP21/C4 locus with only one CYP21 gene and one C4 gene found, whereas in human and mouse these genes are duplicated. These results show the class II I region is very well conserved between pig. human, and mouse, in cont rast with the class I and class II regions, which seem more prone to r earrangements.