Recombination between the S and the H blood group loci in pigs.

The investigation of A-O blood group phenotypes in selected pig families confirms the existence of an S locus which specifically controls the expression of A and O alloantigens. Forty-five informative litters were scored for linkage between the S gene and the H blood group locus. The recombination frequency in 345 offspring was estimated to be 9.56% (33 cross-overs). Specific difficulties involved in the determination of A-O and H phenotypes and the importance of S and H polymorphisms for the determination of Hal genotypes are discussed.