Gene correction in the evolution of the T cell receptor beta chain.

Mutational mechanisms operating at the T cell receptor beta chain locus have been examined by comparison of the CT beta 1 and CT beta 2 gene sequences from Mus pahari, believed to be the oldest living species in the genus Mus, with those of inbred mice. Results indicate that a gene correction event independent of that suggested to have occurred in inbred mice has homogenized the M. pahari CT beta exon 1 sequences, minimizing diversity in this region of the molecule. These observations suggest that correction events such as gene conversion may occur frequently, even in pauci-gene families with as few as two members, and therefore play a significant role in gene diversification or homogenization of small as well as large gene families.