Revealing the unseen: the organizer region of the nucleolus.

Short communication: Chromosome description and localization of Nucleolus Organizing Regions (NORs) by Ag-staining Technique in Alburnus filippii (Cyprinidae, Cypriniformes) in Anzali Lagoon, North of Iran

Genetic linkage map of the nucleolus organizer region in the soybean.

Simple polymorphisms in ribosomal DNA repeats in the nucleolus organizer region (NOR) permitted the development of markers for the genetic mapping of the soybean NOR. The markers map to the top end of soybean linkage group F, one of either telomeric end predicted in the cytogenetic and primary trisomic studies.

Chromosomal stasis in distinct families of marine Percomorpharia from South Atlantic

The weakness of physical barriers in the marine environment and the dispersal potential of fish populations have been invoked as explanations of the apparent karyotype stasis of marine Percomorpha, but several taxa remain poorly studied cytogenetically. To increase the chromosomal data in this fish group, we analyzed cytogenetically three widespread Atlantic species from distinct families: Chae...

Nucleolar dominance and replicative dominance in Drosophila interspecific hybrids.

The replication of the rDNA complement of only one nucleolus organizer region during polytene chromosome formation (replicative dominance) was initially observed in Drosophila melanogaster. Here we demonstrate replicative dominance in Drosophila simulans and D. melanogaster/D. simulans interspecific hybrids. A second nucleolar phenomenon, nucleolar dominance, is observed in the diploid tissue o...

Cytogenetic and random ampliied polymorphic DNA analysis of Leptodactylus species from rural and urban environments (Anura, Amphibia).

Cytogenetic and random amplified polymorphic DNA analyses carried out in the species Leptodactylus podicipinus, L. ocellatus, L. labyrinthicus, and L. fuscus from rural and urban habitats of the northwest region of São Paulo State, Brazil, showed that the karyotypes (2n = 22), constitutive heterochromatin distribution and nucleolus organizer region (NOR) location did not differ between the popu...