Karyotype analysis of chub, Squalius cephalus (Linnaeus, ۱۷۵۸) (Teleostei: Cyprinidae) from Karasu River, Erzurum, Turkey

The karyotypic characteristics of   chub, Squalius cephalus have been investigated by examining metaphase chromosomes spreads obtained from gill and kidney tissues. The fish used in the study were caught with fishing nets from Dumlu Stream, one of the main tributaries of the Karasu River. The live fish were transported to the laboratory,  kept in a well aerated aquarium before analysis and then  were injected intraperitoneally with doses of phytohemagglutinin, ۰.۰۱ ml.g-۱ BW of ۱% solution with ۴۸-h interval to induce cell divisions. At the end of the period, the fish were injected intraperitoneally with doses of colchicine (۰.۰۱ ml.g-۱ BW of ۶% solution) and left for ۳ hours before anesthesia and sacrificing. The best treatment parameters for preparing good metaphase chromosome spreads from the gill and kidney cells were performed as hypotonic  (۰.۰۷۵ M KCl) treatment for ۵۰ minutes, fixation with cold Carnoy solution at ۳:۱ ratio (methanol: acetic acid) and a concentration of ۵% Giemsa for ۳۵ minutes. The diploid chromosome number of this species was ۲n = ۵۰. The fundamental arm number (FN) was ۹۲. The karyotypes were composed of ۵ metacentric, ۱۱ submetacentric, ۵ subtelocentric and ۴ acrocentric chromosome pairs (۱۰ M + ۲۲ SM + ۱۰ ST + ۸ A). No sex chromosomes were cytologically detected in this fish.

Keywords:

Karyogram , Karasu Basin , Chromosomes , FISH