Nucleolus organizer region
Four species of Aplastodiscus and two species of Hypsiboas were cytogenetically compared. Aplastodiscus perviridis, A. cochranae, H. albomarginaus, and H. faber had 2n = 24 chromosomes, while A. albosignatus and A. leucopygius had 2n = 20 and 2n = 18 chromosomes, respectively. Aplastodiscus perviridis and A. cochranae had identical karyotypes, as indicated by their chromosomal morphology, the location of the nucleolus organizer region (NOR) on chromosome pair 12, and the heterochromatin pattern.
A comparative study of holocentric chromosomes in the triatomine species Panstrongylus megistus, Rhodnius pallescens and Triatoma infestans was carried out in order to characterize heterochromatin, rDNA active sites and nucleolar proteins. Cytological preparations of seminiferous tubules were stained by silver impregnation, C banding, fluorochromes cma3/da and dapi/da, and fluorescent in situ hybridization (FISH) with Drosophila melanogaster 28S rDNA probe.