IgG allotypes of the domestic mink: genetics, expression and evolution

A brief review summarized the results we obtained with the identification, analysis of population distribution, genetics, expression, and evolution of 12 IgG allotypes in the American mink and several closely related mustelids. The American mink is a unique species with respect to expressed allotypic polymorphism of Ig lambda chains. In contrast to the rabbit, human, mouse and rat, the phenotypic expression of IgC gamma allotypes shows unusual variations which mask their true genetic relationships (linkage of C gamma genes; C gamma = constant region of IgG chains). The allotypic IgG polymorphism in the American mink during mustelid phylogenesis underwent saltatory change. A parallelism between the data on changes in IgG allotype frequencies in man and mink in disease is emphasized. In mink, these changes are provided by allotype-specific activation of the expression of the 2 CH genes (CH = constant region of the Ig heavy chains). The results make apparent the need of including more taxa in investigations of Ig genetics. In addition, the Aleutian disease of the mink is presented as a model of human disease.