Reconsideration of the Karyological Relationship between Two Japanese Species of Shrew-moles, Dymecodon pilirostris and Urotrichus talpoides

摘要

Details of the karyological relationship between the lesser Japanese shrew-mole Dymecodon pilirostris (2n=34) and the greater Japanese shrew-mole Urotrichus talpoides (2n=34) were examined by five differential-staining techniques, namely, G-, C-, NOR-, Q- and CMA-banding. Staining revealed that thirteen autosomal pairs and the sex chromosomes of the two species exhibited strong homology in terms of banding patterns. The remaining three autosomal pairs, nos. 13, 14 and 15, exhibited distinct interspecific differences both in banding patterns and in the morphology of the respective chromosomes. These interspecific differences can be explained by the presence or absence of an unusual (G-, C-, NOR- and Q-band-negative, but CMA-band-positive) region of chromatin, by the pericentric inversion inv (14) (p 13q31), and by duplication of C-heterochromatin, respectively. It has been suggested that the unusual chromatin found in U. talpoides might contain highly repetitive GC-rich sequences, even though its staining properties appear to be unique and are unlike those of so-called C-heterochromatin, Detailed pair-matching analyses of banded chromosomes led us to revise the relationship, proposed previously by Hamada and Yosida, between D. pilirostris and U. talpoides (Hamada and Yosida, La Kromosomo II-20, 585-590, 1980).