Karyotype, NOR phenotype and C-banding study of Barbus cyclolepis from Greece
Rab, P.; Karakousis, Y.; Rabova, M.
Folia Zoologica 45(Suppl 1): 77-83
Karyotype, distribution of constitutive heterochromatin and number of nucleolar organizer regions (NORs) of the cyprinid fish Barbus cyclolepis were studied. Individuals from the western-most part of the distribution of the species in the Axios (Vardar) River basin, Macedonia, Greece, were examined. The diploid chromosome number was 2n = 100. The chromosome set consisted of 13 pairs of metacentric, 8 pairs of submetacentric, 18 pairs of subtelocentric and 11 pairs of acrocentric chromosomes. The NORs as revealed by silver (Ag) staining were situated in telomeres of the shorter arms of two small sized Subtelocentric chromosome pairs. all examined individuals possessed consistently four Ag-positive NORs and no polymorphism in number of NORs was observed. The amount of C-positive heterochromatin as revealed by C-banding was low as usual in tetraploid barbels but apparently higher than in other European Barbus taxa. Karyotype of B. cyclolepis was remarkably close to that of other European Barbus of the cyclolepis group: it possesses a similar karyotype structure, the identical "barbine" chromosome marker, i. e. large subtelocentric chromosome pair, and the locations of NORs. This study confirms the tetraploid status of B. cyclolepis as suggested earlier by morphological and biochemical studies and documents that this species is the member of the tetraploid lineage of genus Barbus s. str.