Artificial induction of haploid androgenesis in the oyster,Crassostrea rivularis

TLDR: UV irradiation for 50 s at the intensity of 1 820 μW/(cm2s) was considered to be the optimum dose to achieve haploid androgenesis in the C. rivularis and the results of chromosome observation showed that under this condition the haploid rate was the highest.

Abstract: The effects of ultraviolet (UV) irradiation on genetic inactivation of eggs were examined in the oyster,Crassostrea rivularis. In this experiment the eggs treated UV with UV light (254 nm) at intensity of 1 820 μW/(cm2s) for 0 s,10 s,20 s,30 s,40 s,50 s,60 s,70 s,80 s and 90 s were fertilized with normal sperms. The result showed that when eggs were irradiated for 50 s and mixed with normal sperm,the fertilization rate was relatively high (63.5%) and the developmental rate of D-shaped larvae became zero. The results of chromosome observation showed that under this condition the haploid rate was the highest (50.4%). The obviously improved survival of trochophore larvae with a peak at 50 s UV exposure suggested the presence of a Hertwig effect in the androgenesis of C. rivularis. As effective induction of haploid androgenesis required the inactivation of egg DNA and high fertilization rate,UV irradiation for 50 s at the intensity of 1 820 μW/(cm2s) was considered to be the optimum dose to achieve haploid androgenesis in the C. rivularis. The rates of the fertilization,survival at the early embryo stage,and the development of D-shaped larvae decreased with increasing irradiation time,and the development of the genetically inactivated eggs fertilized with normal sperm terminated before reaching D-shaped stage.