Chromosome Banding in African Catfishes: Nucleolar Organizer Regions in Five Species of the Genus Synodontis and One of the Genus Hemisynodontis (Pisces, Mochokidae)

SUMMARY

An analysis of the nucleolar organizer regions (NORs) by silver staining of five species of the genus Synodontis, S. budgetti, S. sorex, S. violaceus, S. schall, S. filamentosus and one of the genus Hemisynodontis, H. membranaceus is reported. The six species presented only one pair of NORs bearing homologs. These homologs showed same morphology and their sizes where relatively similar to each other among the species. These findings suggest that in this genera, the NORs bearing chromosomes might be conserved and could not be used as a criterium for species identification.