Polymorphism of T-cell receptor genes among laboratory and wild mice: diverse origins of laboratory mice.

Southern blots of genomic DNA from 23 strains of laboratory mice and 19 individual wild mice were examined for restriction fragment length polymorphisms in their loci encoding the T-cell receptors (Tcr): the constant regions of the alpha, beta, and gamma chains (C alpha, C beta, and C gamma) and a variable region family of the beta chain (V beta 8). Only a few polymorphisms were observed for each locus in the laboratory mice after using three restriction enzymes, Bam HI, Eco RI, and Hind III. All the laboratory mice examined fall into one of two types for the C alpha, C beta, and V beta 8 loci and one of three types for the C gamma. These types are found in some of the wild mice studied, indicating that they were already present in the founder mice of laboratory mouse strains. In contrast, the Tcr genes are highly polymorphic among wild mice. Analysis of the polymorphisms in these loci suggests that laboratory mice have inherited their genes not only from Mus musculus domesticus, but also from other subspecies, and much more than previously believed from Asian subspecies.