Three populations of the genus Crenicichla, namely Crenicichla iguassuensis, Crenicichla sp 1 and Crenicichla sp 2, from the Iguaçu River, were analyzed cytogenetically, and their nucleolus organizer regions, constitutive heterochromatin distribution and chromomycin A3 markings were studied. Karyotype analyses showed a diploid number of 48 chromosomes, made up of 2 metacentric pairs, 2 submetac...

The chromosomal banding properties of Oxynoemacheilus simavicus (Balık & Bănărescu, 1978) were revealed out by C-banding and silver staining. Constitutive heterochromatin regions determined on the pericentromeres most chromosomes C-banding. Otherwise, nucleolus organizer (NORs) observed short (p) arms one middle-sized submetacentric (sm) chromosome pair Also, Ag-NOR size number polymorphism...

The chromosome modal number in Muscoidea Diptera is 2n=12, including five pairs of autosomes and one sex chromosome pair. Nevertheless, some species with 2n=10 chromosomes have been described, all of them from the Muscidae family. We analyzed the karyotype of some Muscidae species from different subfamilies and compared the obtained data with the karyotypes of some species of the families Calli...

The chromosome complement of Chiropodomys gliroides from Peninsular Malaysia consists of two pairs of nucleolar organizer regions (NORs) – the longest acrocentric pair and the small metacentric. The NORs in both pairs are located at the terminal end; in the long acrocentric at the end of the long arm. In the metaphases, at least one element in both pairs exhibited the presence of Ag-NOR activit...

The Nucleolar Organizer Regions (NORs) were first described by Heitz (1931) and McClintock (1934) as weakly stained chromatin regions around which, at the end of telophase, nucleoli are reformed after their disappearance during the mitotic phase of the cell cycle. NORs, located on short arm of acrocentric chromrsomes (Chromosome number 13,14,15,21 and 22) contain ribosomal genes which encode fo...