A comprehensive search for segregation distortion in HLA.

Segregation distortion, the non-Mendelian segregation of gametes, has been well documented among diverse groups of organisms. These cases are characterized by extreme segregation ratios found only in males. Previous reports have suggested the existence of segregation distortion operating in the HLA system of humans, a tightly linked complex of genes which regulates the immune system. In mice, some alleles of the T/t complex, which is linked to H-2 (the HLA homologue of mice), cause extreme segregation distortion in wild mice populations. Here we report on the examination of a large body of pedigree data on non-diseased families, scored for the alleles of five HLA region loci. We searched for segregation distortion on the basis of five different models of inheritance: allelic, haplotypic, genotypic, diffuse occurrence in families, and autosomal effects on the sex ratio. There was no clear evidence for segregation distortion. In particular, the possibility of extreme levels of segregation distortion was firmly rejected in the populations examined, thus reducing the likelihood of common distortion-causing HLA associated haplotypes in our species.