KARYOTYPE, NOR PHENOTYPE AND C-BANDING STUDY OF BARBUS-CYCLOLEPIS FROM GREECE

Karyotype, distribution of constitutive heterochromatin and number of nucleolar organizer regions (NORs) of the cyprinid fish Barbus cyclole pis were studied. Individuals from the westernmost part of the distrib ution of the species in the Aries (Vardar) River basin, Macedonia, Gre ece, were examined. The diploid chromosome number was 2n = 100. The ch romosome set consisted of 13 pairs of metacentric, 8 pairs of submetac entric, 18 pairs of subtelocentric and 11 pairs of acrocentric chromos omes. The NORs as revealed by silver (Ag) staining were situated in te lomeres of the shorter arms of two small sized subtelocentric chromoso me pairs. ail examined individuals possessed consistently four A,a-pos itive NORs and no polymorhism in number of NORs was observed. The amou nt of C-positive heterochromatin as revealed by C-banding was low as u sual in tetraploid barbels but apparently higher than in other Europea n Barbus taxa. Karyotype of B. cyclolepis was remarkably close to that of other European Barbus of the cyclolepis group: it possesses a simi lar 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 suggest ed earlier by morphological and biochemical studies and documents that this species is the member of the tetraploid lineage of genus Barbus s. str.