本邦産イモリの核型と構成的異質染色質の局在パターンについて

Karyotypes of male and female Japanese newts, Cynops pyrrhogaster, were studied by the preparation of conventional Giemsa stain and by C-staining technique. Twelve pairs of somatic chromosomes consisted of eight metacentric and four submetacentric homologues. Both male and female karyotypes have identical morphology and no manifestation of heteromorphism of chromosomes defined as a sex-specific pair. Meiotic chromosomes were also examined in male individuals together with their gut tracts. All bivalents at prometaphase of first meiotic division indicated the interstitial chiasmata which were terminalized on all chromosome arms. No end-to-end paired bivalent was seen.
C-banding appeared most intense in the pericentric region of either both chromosome arms or on a single arm of submetacentric chromosomes. Centric heterochromatin was faintly detected in a few chromosomes. The banding pattern of mitotic and meiotic chromosomes of C. pyrrhogaster revealed the dissimilarity of localization of constitutive heterochromatin with related European Triturus, whose karyotypes were quite similar each other.