A polymerase chain reaction (PCR) technique associated with restriction fragment length polymorphism (RFLP) analysis has been developed for typing the second exon of the caprine Mhc class II DRB gene. By using a maximum of three restriction enzymes, corresponding to different combinations of RsaI, BsaI, AccI, NdeII, HaeIII and HpaII, this procedure allows to distinguish unequivocally 18 of the 22 caprine DRB alleles. Forty goats of several breeds were typed with this technique and two new RsaI restriction patterns which did not match with previously published sequence data were identified. Close associations have been found between RFLPs and amino acid substitutions at positions which are expected to be involved in the formation of the antigen-recognition site (ARS) of the DR molecule. These results suggest that PCR-RFLP may be a useful tool in typing the caprine DRB gene and in relating amino acid substitutions at the APS of the DR molecule with disease resistance.
- DRB polymorphism
- antigen-binding site