The structure of a mutant H-2 gene suggests that the generation of polymorphism in H-2 genes may occur by gene conversion-like events

We have cloned a mutant allele of the H-2K^b gene known as H-2K^bml. DNA sequence analysis of this gene shows that it is the result of an intergenic exchange of DNA (gene conversion) which results in the conversion of a short internal segment of the H-2K^b to the corresponding sequence of another H-2 gene. We suggest that this type of gene conversion is widespread in H-2 genes and that it is a major force in the generation of polymorphism in H-2 genes.