A karyological analysis of Puntius conchonius (Hamilton, 1822) (Pisces, Cyprinidae), a new cytotype from Dal Lake Srinagar Kashmir, Jammu and Kashmir (JK), India

Abstract

The karyotypic and cytological characteristics of Rosy barb, Puntius conchonius (Hamilton, 1822) (cyprinidae) were investigated by examining metaphase chromosomes spreads from the anterior kidney following Thorgaard and Disney (1990). The fishes were obtained from the local fishermen and transported live to the Limnology and Fisheries Laboratory of Centre of Research for Development, University of Kashmir. Ten fish were injected intraperitoneally with two doses of phytohemagglutinin (PHA), 4 µg g-1body weight with a 20 h interval to induce cell division. After 8 h in 20°C water, the fish were injected intraperitoneally with colchicine 0.05% at 0.5 ml/50 g body weight to depress the cell division in the metaphase stage and left for 2 to 3 h before sacrificing. Kidney and gill epithelia were used for karyotype analysis. The diploid chromosome number of the fish was 2n = 50, consisting of 11 pairs of metacentric, 8 pairs of submetacentric and 6 pairs of telocentric chromosomes respectively. Centromeric index, arm ratio and Fundamental Number were determined as 0 to 50, 1-∞ and 88 respectively. No heteromorphic sex chromosomes were cytologically detected. Key words: Chromosome, Puntius conchonius, Dal Lake, karyotype.