Gynogenetic Tetraploid Larvae of the Pacific Oyster Crassostrea gigas Induced by Inhibition of the 1st and 2nd Meiotic Divisions

The induction of gynogenetic tetraploids by the suppression of the meiotic division in the Pacific oyster Crassostrea gigas was attempted in three trials using the treatments of cytochalasin B (0.5μg/mL; CB). The effects of various durations of CB treatment on tetraploid induction frequency were examined. Haploid gynogenesis was induced by sperm which were UV-irradiated for 60s at an intensity of 72erg/mm^2/s. CB treatment was effective in inhibiting meiosis, and the optimum time for the suppression of both the 1st and 2nd polar bodies was from 10 to 45min postinsemination, yielding 51.4% gynogenetic tetraploids. The results of this study suggest the possibility of producing gynogenetic tetraploid Pacific oysters