Karyotyping of Vimba vimba persa

Abstract

The chromosome number and type as well as karyotype in Vimba vimba persa were studied. A total of 200 larvae and 10 fingerlings of this species with an average weight of 30.2g obtained from Shahid Ansari fish hatchery. To arrest mitosis in metaphase, larvae under study were placed in a 0.05% solution of colchicine for a period of 6h while the fingerlings were given an intramuscular injection of 0.01% colchicine. The tissues were let to stand in a hypotonic solution of 0.075M KCl and were then treated with a fixative (Carnoy's solution) in three steps. The chromosomes were then stained with 10% Giemsa solution for 20 min (larvae) and 30 min (fingerlings) and examined under a light microscope. 100 metaphase plates were studied in V. vimba persa larvae and 200 metaphase plates were studied for fingerlings. Based on the count of 300 metaphase plates 74.67% showed 2n=50, 14.67% showed 2n=48 and in 4.67% 2n=49. Based on statistical analysis the chromosome number in this species was calculated as 2n=50 (49.54±0.11) and the number of chromosome arms (NF) was determined as 90. Appropriate metaphase plates were photographed in order to prepare karyotype. The size of the chromosomes (short and long arms), relative length of chromosome and centromere index was calculated. By arranging homologous chromosomes beside each other the chromosome formula was calculated as 7 pairs of Metacentric, 13 pairs of Sub­ Metacentric and 5 pairs of Sub-Telocentric or Acrocentric chromosomes (7M±13Sm±5St/A). On the basis of the number and type of chromosomes, the karyotype obtained for this species was similar to that for other species belonging to the same genus.