The nature of the DR beta II pseudogene in a haplotype of the DRw52 supertypic group was investigated by nucleotide sequence analysis. It revealed several deleterious mutations in the signal sequence and second domain regions in addition to the complete absence of the first domain and adjacent sequences. No expression of DR beta II pseudogene mRNA can be detected. The same DR beta II pseudogene is probably present in other members of the DRw52 supertypic group. The pattern of mutations in this DR beta II pseudogene is different from that observed in the DR beta pseudogene of the DRw53 supertypic group, indicating a distinct evolutionary pathway for these two groups of DR haplotypes.