The linkage relationships of the beta and delta hemoglobin genes.

Three new families providing information on the linkage relationships between the delta and beta hemoglobin loci are reported. One of the families contains the first reported individuals having Hb S and Hb B2 in coupling. Analysis of the information found in the literture is compatible with a recombination frequency of 3 percent between beta thalassemia and the delta structural locus. This highly improbable frequency might be explained by either diagnostic errors or paternity problems in the pedigrees containing recombinants or by the conceivable possibility that certain thalassemia genes increase the probability for recombination in the chromosomal region containing the non alpha globin genes.