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 intestina l receptors to E. coli adhesins (K88abR, K88acR) and at the transferri n (TF) locus was studied in 38 pig families including 273 piglets. The TF locus showed a segregation deviation towards the B variant while e ach 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 f amilies were selected to test linkage and estimate recombination rates (B). Our results demonstrate that the two K88 receptor loci are close ly linked (B = 0.02) with a maximum lod score value (Z(m)) of 46.0. In addition, they are linked to the TF locus, 0 = 0.14, Z(m) = 19.6 for the K88abR locus and 0 = 0.16, Z(m) = 17.9 for the K88acR locus. The e stimated recombination rates, smaller in males than in females, are co nsistent with the order TF-K88abR-K88acR. This linkage thus localizes the K88 loci, as the TF locus, on chromosome 13.