INTRODUCTION OF TETRAPLOIDY IN Rana tigrina (INDIAN BULL FROG) BY THERMAL, HYDROSTATIC PRESSURE AND CHEMICAL SHOCKS

Introduction of tertraploidy in R. tigrina was attempted, using thermal, hydrostatic pressure and chemical shocks. Heat and pressure shocks induced 100% tetraploidy. Chromosome count and RBC micro measurement were found to be reliable method for determination of ploidy. It can be achieved by using Anaesthetic- ether for giving Anaesthesia to frog. While Colchicine (0.02%) as a mitotic-inhibitor [1] and hypotonic -solution, (1952 Hugs, Makino, and Nishimpura), Methanol: Glacial acid (3:1)as freshly prepared cold-fixative, Giemsa stock-solution for staining chromosome,(Hsu and Hsu Pomerat [2] as well as Phosphate Buffer Salt (PBS) is used. Trypsin- solution is used for G-banding (Plate-5a). All the above solution were prepared using different types of chemical substances like, Sodium citrate, distilled water, Giemsa stock-solution by Giemsa powder, glycerol, sodium chloride, potassium – chloride, glucose, sodium bicarbonate etc [3]. (Tijio and Puck 1958). Karyotype is obtained in the animals like fishes, amphibians, mammals like rats can also be studied.

Then chromosomes are arranged on the basis of long arm and short arm (L/S) and classified as metaphase chromosome, as meta-centric, sub-metacentric, and acrocentric respectively. It can be obtained by centrifugation, air-dry method was followed for slide preparation. After drying slides were stained with 2% Giemsa for 15 minutes, and washed thoroughly in distilled water for clear-differentiation, under the microscope.

Then after observing these plates, were selected and analyzed. Finally, good clear – differentiated slide were selected. Tetraploid slide was taken in which we got 52 chromosomes in plate number 5a-for G-banding and 5b for tetraploidy which is obtained by above mentioned method. Then Idiogram drawn on X- axis chromosome number and on Y-axis relative length. So in this work , which was carried out we got results similar to Stephenson (1977).