The context of T-cell receptor gamma chain genes among wild mouse species.

We have examined the context of mouse T-cell receptor gamma (Tcr gamma) chain variable (V gamma) and constant (C gamma) genes among a panel of geographically isolated species of mice. Our Southern hybridization survey with C gamma reveals that essentially three C gamma genes are found among mouse species extending phylogenetically from inbred mice through the feral species Mus pahari. However, a V gamma DNA probe detects three to nine V gamma restriction fragment bands among the same group of mice. These results suggest that certain feral mice such as M. pahari, M. platythrix, and M. shortridgei have amplified numbers of V gamma genes. Studies of individual mice from these particular species indicate the highly amplified V gamma content is not the result of a catastrophic gene duplication or deletion event. We conclude that certain species of mice maintain increased content of V gamma presumably for increased diversity in a T-cell response.