魁蚶雌核发育的人工诱导

Artificial induction of gynogenesis in Scapharca broughtonii

研究了魁蚶(Scapharca broughtonii)雌核发育的人工诱导条件。用强度为2 561μW/(cm2.s)的紫外线(254 nm)照射不同时间的精子与正常卵子受精,发现随照射时间的增加,卵裂率、早期胚胎存活率和D形幼虫发生率总体呈下降趋势,遗传失活的精子与正常卵子受精后其胚胎发育至D形幼虫前期停止。经紫外线照射的精子受精后所产生的单倍体胚胎发育速度慢于正常受精所产生的二倍体胚胎,各照射组均出现非整倍体。45 s照射组中早期胚胎存活率达到67.2%,D形幼虫发生率为0,单倍体率达到最高值37.1%,出现Hertwig效应。结果表明在强度2 561μW/(cm2.s)的紫外线下照射45 s是获得魁蚶雌核发育单倍体的最适条件。研究结果为魁蚶雌核发育二倍体的人工诱导奠定了重要基础。

The effects of ultraviolet （UV） irradiation on genetic inactivation of sperm were examined in the Scapharca broughtonii. The sperms irradiated by UV at 2 561 uW/（cm2.s） for various durations were fertilized with normal eggs. With increasing irradiation time, the rates of cleavage, survival at the early embryo stage, and development of D-larvae decreased, and the development of the eggs fertilized with the genetically inactivated sperm terminated before reaching the D-larvae stage. The development speed of gynogenetic embryos was slower than that of the control group, and aneuploids were found in this study. The Hertwig effect was observed. When sperms were irradiated for 45 s, the survival rate at the early embryo stage was 67.2%, the developmental rate of D-larvae became zero, and the rate of haploid reached the highest value of 37.1%. UV irradiation of 2 561 uW/（cm2.s） for 45 s was considered to be the optimum dose to achieve haploid gynogenesis in the S. broughtonii. The results obtained here will be useful for artificial induction of gynogenetic diploids in this species.