Linkage studies between the halothane (Hal), phosphohexose isomerase (Phi) and the S(A -O) and H red blood cell loci of Pietrain/ Hampshire and Landrace pigs

Abstract

Frequency of blood group factors at the A-O and H loci were markedly altered within halothane positive (HP) and halothane negative (HN) composite synthetic Pietrian/Hampshire lines (PTH) over 4 generations of selection. Linkage studies on the litters from 45 double backcross and 20 mixed and intercross matings, involving the S(A-O), H, Phi and Hal loci, were made in the PTH line and halothane positive and negative selected British Landrace lines. Crossing-over frequencies of 0.05 .+-. 0.04, 0.05 .+-. 0.03 and 0.1 .+-. 0.03 were established between Phi and Hal, H and Hal, and Phi and H, respectively. An unequal crossing-over frequency between Phi and H was found when the alleles Ha and Hcd were compared. The difference in recombination frequency between the Ha and Hcd alleles amounted to 0.04 to 0.06. No crossovers were observed between the S(A-O) and Phi, H or Hal loci in 15 families studied. The position of the S locus in relation to the other loci could not be established, but statistical evidence of association favors a haplotype sequence of Phi-Hal-S-H.