Genetic variation in a subterranean mammal, Spalax ehrenbergi

The mole rat, Spalax ehrenbergi, occurs in Israel and vicinity as four clinally distributed chromosome forms which are probably sibling species. By the method of starch gel electrophoresis of enzymes, genetic variation of 13 proteins controlled by 17 loci was studied in a total of 383 animals from the four chromosome forms. There was little genetic difference among the four groups, suggesting that speciation can occur without changes in many of the genes. Average degree of polymorphism per chromosome form was 19.1%, ranging from 5.9 to 29.4% for different chromosome forms. Individuals were, on the average, heterozygous at 3.7% of their loci, ranging from 1.8 to 5.6% in the four different chromosome forms. These relatively low values of genetic variation may possibly be associated in part with the ecologically relatively monotonous subterranean niche of Spalax.