Map arrangement of the SLA chromosomal region and the J and C blood group loci in the pig

Linkage studies of three-point crosses (triple backcross matings) showed that the linear sequence of three of the pig's immunogenetic traits — the SLA major histocompatibility complex and the J and C blood group loci — is SLA-J-C . Andresen & Baker (1964) and Rasmusen (1965) described close linkage between the J and C blood group loci and respectively found their recombination frequency to be 5.29 ± 1.1 % and 7.00 ± 3.4 %; by combining the data the exact frequency was determined at 5.75 ± 0.79 % (Muir & Rasmusen, 1974). Later, linkage of the SLA major histocompatibility complex with both J (Hruban et al., 1976) and C (Hruban et al., 1977) erythrocytic loci was found. The maximum tabular lod score values were found in the recombination fraction Θ= 0.10 in comparison of SLA and J and in the fraction Θ= 0.20 in comparison of SLA and C (Hruban et al., 1977).