Analysis of class II genes of the chicken MHC (B) by use of human DNA probes.

Class II genes of the major histocompatibility complex (MHC) in the chicken have been investigated by Southern blot analysis using human cDNA probes for DQ alpha, DQ beta, DR alpha, and DR beta. Both beta probes but not the alpha probes cross-hybridized well with chicken DNA. The results indicated that the beta probes hybridized with at least two beta genes in the chicken MHC and there was no clear indication of a DQ-DR subdivision of chicken class II beta genes. The possibility of using human beta probes for MHC typing in the chicken was tested by using two homozygous individuals for each of 20 different, serologically defined, MHC (B) haplotypes originating from the domestic breeds of White Leghorn and Rhode Island Red, or from Red Jungle Fowl (the wild ancestral form). Genomic DNA samples from these individuals were digested with any one of the Eco RI and Pvu II restriction enzymes and hybridized with the DR beta probe. Restriction fragment length polymorphism (RFLP) was obtained with Pvu II only, which resolved seven different RFLP types. There was an excellent correlation between these RFLP types and the serological B typing since the RFLP type was identical within each pair of homozygotes. In addition to this broad survey of many haplotypes, a more detailed comparison was carried out on B21-like haplotypes originating from different breeds. No differences in restriction fragment patterns among these haplotypes could be resolved using any of the restriction enzymes Bg1 II, Eco RI, Hind III, Pst I, Pvu II, and Taq I.