Numerous variants of the Rh blood group system, discovered by Levine and St
etson in 1939, have been detected and more than forty antigens have been id
entified. By performing the molecular genetic analysis of the introns as we
ll as the exons in both RH genes, it was elucidated that Rh variants were g
enerated by gene conversion or recombination, deletions, or mutations. For
understanding the generation of many Rh variants and Rh antigens in detail,
it is necessary to analyze not only the RHCE and RHD genes but also the st
ructure and the physical distance between both these RH genes. In order to
achieve the aforesaid purpose, the spacer region between the RHD and RHCE g
enes were amplified by the long PCR method. Therefore the full spacer regio
n was determined to be 12159 bp in length and contained the Alu consensus s
equences and the putative CpG island. It was probable that the duplication
of both RH genes occurred within about 12 kb region. Analysis of the spacer
region provides new information for the research on the transcription-cont
rol region, the molecular evolution of RH genes, Rh variants, and the delet
ion of the RHD gene in Rh blood group system. (C) 1999 Academic Press.