Induction of gynogenesis in endangered sarpunti, Pun tius sarana (Hamilton) and evidence for female homogamety

The experiment was conducted to optimize a procedure of gynogenesis induction in Puntius sarana by suppressing meiotic cell division in fertilized eggs. Gynogenesis was induced by fertilizing normal eggs with genetically inactivated sperm followed by heat shocking. The sperm were inactivated by exposing them to a UV dose of 250 µW cm^sup -2^ for 2 min at a concentration of 1 x 10^sup 8^ sperm/ml. Seven different heat shock temperatures viz., 32, 34, 36, 38, 39, 40 and 41 °C were tested for different lengths of time to find out the best combination of heat shock temperature and shock duration. Exposure of inseminated eggs to heat shock at 39 °C for 2-4 mm after fertilization increased the yield of diploid gynogenetic offspring. Early developmental stages of P. sarana were studied to know the life history of the female homogamety. Histological examination of the gonads of the diploid gynogens revealed that all the fishes were female, indicating female homogamety (XX) in P. sarana. [PUBLICATION ABSTRACT]