Karyotype analysis of Barbus barbus L. and Barbus peloponnensius V. (Cyprinidae) and frequencies of breaks and gap-type structural chromosome changesin fishes from the river Vapa

The chromosomes of B. barbus L. and B. peloponnensius V. from the river Vap a were cytogenetically studied.. barbus has a diploid chromosome number 2n= 100. The karyotype consists of 30 metacentrics, 18 submetacentrics and suba crocentrics and 52 acrocentric chromosomes. B. peloponnensius V. also has t he same diploid chromosome number 2n=100, but the karyotype contains 10 met acentrics, 44 submetacentrics subacrocentrics and 46 acrocentric chromosome s. The frequencies of the breaks and gap-type structural chromosome aberration s were analysed. Relatively low frequencies were detected (lower than 1%) a nd they were at the level that might be found in the laboratory animal cont rols and in the tissue culture controls. The data obtained indicate that in the environmental conditions of the fishes studied, there were no genotoxi c agents which could express their effects on the chromosomes of these livi ng organisms.