Ellobius lutescens Th. (Rhodentia, Microtinae): Q-, R-, and replication banding patterns. Chromosome 1 polymorphism in the male and presumptive heterogamety in the female.

Five specimens of Ellobius lutescens, four males and one female, were studied by several banding methods. Structural polymorphism occurred in the longest chromosome pair of the karyotype of two males: a pericentric inversion in one animal and a paracentric inversion in the other. In the female studied, one chromosome 1 differs from those of the males by a marked elongation of a proximal euchromatic band in the long arm. Thus, the female seems to represent the heterogametic sex. Chromosome 9 showed the same banding pattern in both sexes. The possible meaning of this chromosome constitution for the sex-determining mechanism of E. lutescens is discussed.