1980 Volume 55 Issue 4 Pages 289-296
The mitochondrial DNAs of house mouse, Mus musculus in twenty-five different laboratory strains showed identical cleavage patterns on digestion with nine different restriction endonucleases. The cleavage patterns were identical to those of Canadian wild mice, M. m. domesticus but clearly different from the patterns of three Asian subspecies, M. m. bactrianus, M. m. castaneus and M. m. molossinus. Based on comparison of the cleavage maps of the four subspecies, the time of divergence between M. m. domesticus and three Asian subspecies was estimated to be 1-2.5×106 years. These results suggest that the genetic background of laboratory mice is mainly derived from M. m. domesticus.