Mus Terricolor (rodentia, Muridae) Complex: Chromosomal Polymorphism

Mus terricolor chromosomal types I, II, III from different places of India were cytogenetically analyzed. Chromosome types II and III showed polymorphic pericentric inversions of autosomes 2 and 5 present in homozygous or heterozygous condition in the populations. Moreover, besides fixed heterochromatic arms on autosomes 1, 3, and 6; the autosome 8 in terricolor type III showed a large heterochromatic block in heterozygous condition. Other autosomes showed heterogeneity in C-band positive heterochromatin in all the chromosome types. Differential C-band staining were also observed on the short arms of X, the entire Y and on the telomere of X and Y. The results suggest a unique situation of speciation in M. terricolor complex.