Evidence for linkage between K88ab, K88ac intestinal receptors to Escherichia coli and transferrin loci in pigs

Segregation at the loci coding for the K88ab and K88ac small intestinal receptors to E. coli adhesins (K88abR, K88acR) and at the transferrin (TF) locus was studied in 38 pig families including 273 piglets. The TF locus showed a segregation deviation towards the B variant while each of the K88 receptors behaved as a single autosomal dominant gene. Recombinants between K88abR and K88acR provide evidence that they are under the control of two different loci. Thirty-two triple backcross families were selected to test linkage and estimate recombination rates (θ). Our results demonstrate that the two K88 receptor loci are closely linked (θ= 0.02) with a maximum lod score value (Z_m) of 46.0. In addition, they are linked to the TF locus, θ= 0.14, Z_m= 19.6 for the K88abR locus and θ= 0.16, Z_m= 17.9 for the K88acR locus. The estimated recombination rates, smaller in males than in females, are consistent with the order TF-K88abR-K88acR. This linkage thus localizes the K88 loci, as the TF locus, on chromosome 13.