Evolutionary Genetics, Centre for Ecological and Evolutionary Studies, University of Groningen, Netherlands.
Science. 2010 Apr 30;328(5978):620-3. doi: 10.1126/science.1185805.
All insects in the order Hymenoptera have haplodiploid sex determination, in which males emerge from haploid unfertilized eggs and females are diploid. Sex determination in the honeybee Apis mellifera is controlled by the complementary sex determination (csd) locus, but the mechanisms controlling sex determination in other Hymenoptera without csd are unknown. We identified the sex-determination system of the parasitic wasp Nasonia, which has no csd locus. Instead, maternal input of Nasonia vitripennis transformer (Nvtra) messenger RNA, in combination with specific zygotic Nvtra transcription, in which Nvtra autoregulates female-specific splicing, is essential for female development. Our data indicate that males develop as a result of maternal imprinting that prevents zygotic transcription of the maternally derived Nvtra allele in unfertilized eggs. Upon fertilization, zygotic Nvtra transcription is initiated, which autoregulates the female-specific transcript, leading to female development.
膜翅目所有昆虫的性决定方式都是单倍体孤雌生殖，其中雄性由未受精的单倍体卵子发育而来，而雌性是二倍体。蜜蜂的性决定由互补性别决定（csd）基因座控制，但没有 csd 基因座的其他膜翅目昆虫的性别决定机制尚不清楚。我们鉴定了寄生蜂纳索虫的性别决定系统，纳索虫没有 csd 基因座。相反，纳索虫转化器（Nvtra）信使 RNA 的母体输入，与特定的合子 Nvtra 转录相结合，其中 Nvtra 自我调节雌性特异性剪接，对于雌性发育是必不可少的。我们的数据表明，雄性的发育是由于母体印记，阻止了未受精卵子中母体来源的 Nvtra 等位基因的合子转录。受精后，合子 Nvtra 转录被启动，它自我调节雌性特异性转录本，导致雌性发育。
