Wertheim Bregje, Kraaijeveld Alex R, Hopkins Meirion G, Walther Boer Mark, Godfray H Charles J
Centre for Evolutionary Genomics, University College London, Gower Street, London WC1E 6BT, UK.
Mol Ecol. 2011 Mar;20(5):932-49. doi: 10.1111/j.1365-294X.2010.04911.x. Epub 2010 Nov 9.
Individual hosts normally respond to parasite attack by launching an acute immune response (a phenotypic plastic response), while host populations can respond in the longer term by evolving higher level of defence against parasites. Little is known about the genetics of the evolved response: the identity and number of genes involved and whether it involves a pre-activation of the regulatory systems governing the plastic response. We explored these questions by surveying transcriptional changes in a Drosophila melanogaster strain artificially selected for resistance against the hymenopteran endoparasitoid Asobara tabida. Using micro-arrays, we profiled gene expression at seven time points during development (from the egg to the second instar larva) and found a large number of genes (almost 900) with altered expression levels. Bioinformatic analysis showed that some were involved in immunity or defence-associated functions but many were not. Previously, we had defined a set of genes whose level of expression changed after parasitoid attack and a comparison with the present set showed a significant though comparatively small overlap. This suggests that the evolutionary response to parasitism is not a simple pre-activation of the plastic, acute response. We also found overlap in the genes involved in the evolutionary response to parasitism and to other biotic and abiotic stressors, perhaps suggesting a 'module' of genes involved in a generalized stress response as has been found in other organisms.
个体宿主通常通过启动急性免疫反应（一种表型可塑性反应）来应对寄生虫攻击，而宿主种群可以通过进化出更高水平的抗寄生虫防御能力在更长期内做出反应。关于进化反应的遗传学我们知之甚少：涉及的基因的身份和数量，以及它是否涉及对控制可塑性反应的调节系统的预激活。我们通过调查人工选择的对膜翅目内寄生蜂塔氏阿索茧蜂具有抗性的黑腹果蝇品系中的转录变化来探索这些问题。使用微阵列，我们在发育的七个时间点（从卵到二龄幼虫）分析了基因表达，发现大量基因（近900个）的表达水平发生了变化。生物信息学分析表明，一些基因参与免疫或防御相关功能，但许多基因并非如此。此前，我们定义了一组在寄生蜂攻击后表达水平发生变化的基因，与当前这组基因的比较显示出显著但相对较小的重叠。这表明对寄生的进化反应不是可塑性急性反应的简单预激活。我们还发现参与对寄生的进化反应以及对其他生物和非生物应激源的反应的基因存在重叠，这可能表明存在一个参与广义应激反应的基因“模块”，正如在其他生物体中所发现的那样。
