Evolutionary Developmental Biology Research Group, Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, OX3 0BP, UK.
BMC Genomics. 2013 Apr 26;14:283. doi: 10.1186/1471-2164-14-283.
Butterflies are popular model organisms to study physiological mechanisms underlying variability in oogenesis and egg provisioning in response to environmental conditions. Nothing is known, however, about; the developmental mechanisms governing butterfly oogenesis, how polarity in the oocyte is established, or which particular maternal effect genes regulate early embryogenesis. To gain insights into these developmental mechanisms and to identify the conserved and divergent aspects of butterfly oogenesis, we analysed a de novo ovarian transcriptome of the Speckled Wood butterfly Pararge aegeria (L.), and compared the results with known model organisms such as Drosophila melanogaster and Bombyx mori.
A total of 17306 contigs were annotated, with 30% possibly novel or highly divergent sequences observed. Pararge aegeria females expressed 74.5% of the genes that are known to be essential for D. melanogaster oogenesis. We discuss the genes involved in all aspects of oogenesis, including vitellogenesis and choriogenesis, plus those implicated in hormonal control of oogenesis and transgenerational hormonal effects in great detail. Compared to other insects, a number of significant differences were observed in; the genes involved in stem cell maintenance and differentiation in the germarium, establishment of oocyte polarity, and in several aspects of maternal regulation of zygotic development.
This study provides valuable resources to investigate a number of divergent aspects of butterfly oogenesis requiring further research. In order to fully unscramble butterfly oogenesis, we also now also have the resources to investigate expression patterns of oogenesis genes under a range of environmental conditions, and to establish their function.
蝴蝶是研究卵发生和卵子供应对环境条件变化的生理机制的热门模式生物。然而，人们对以下方面知之甚少：控制蝴蝶卵发生的发育机制、卵母细胞极性的建立方式，以及哪些特定的母体效应基因调控早期胚胎发生。为了深入了解这些发育机制，并确定蝴蝶卵发生的保守和差异方面，我们分析了 Speckled Wood 蝴蝶 Pararge aegeria（L.）的从头卵巢转录组，并将结果与已知的模式生物如 Drosophila melanogaster 和 Bombyx mori 进行了比较。
共注释了 17306 个连续序列，其中观察到 30%可能是新的或高度分化的序列。Pararge aegeria 雌性表达了已知对 D. melanogaster 卵发生至关重要的 74.5%的基因。我们详细讨论了涉及卵发生各个方面的基因，包括卵黄发生和卵壳发生，以及涉及卵发生激素控制和跨代激素效应的基因。与其他昆虫相比，在生殖腺中干细胞维持和分化、卵母细胞极性的建立以及母体对合子发育的几个方面的调控等方面观察到了一些显著的差异。
本研究为研究蝴蝶卵发生的许多需要进一步研究的不同方面提供了有价值的资源。为了全面阐明蝴蝶卵发生，我们现在也有资源研究卵发生基因在一系列环境条件下的表达模式，并确定它们的功能。
