Data on the linkage relationships of the HL‐A and α‐haptoglobin loci in man

The possibility of linkage between the locus for the human lymphocyte histocompatibility system, HL-A, and the locus for the a-chain of haptoglobin, Hp, was first suggested by Amos et al. (1970). In the investigation of an Amish isolate they studied the linkage relationships of HL-A with several red cell antigens and Berum proteins. The only suggestion of linkage was between HL-A and Hp. Amongst sixty-four children from eleven informative families they found nineteen who would represent recombinant types. The authors considered that the probability of linkage was 0.7658. In a subsequent paper by Bias et al. (1970), thirty-three informative families were analysed, both Amish and non-Amish, and including those previously reported. A recombinant fraction of 0.25 was found with a peak lod of 4.0. They estimated that there was a probability of 0.98 that HL-A is linked to Hp and consequently located on chromosome 16 (Robson et al. 1969; Magenis, Hecht & Lovrien 1970). We wish to report the results of linkage calculations on forty-five families which are informative for HL-A and haptoglobin.