Evolutionary origins of a novel host plant detoxification gene in butterflies
Evolutionary origins of a novel host plant detoxification gene in butterflies
复制标题
DOI：
10.1093/molbev/msn014
复制
发表时间：
2008-05-01
影响因子：
10.7
通讯作者：
Vogel, Heiko
中科院分区：
文献类型：
--
作者：
Fischer, Hanna M.;Wheat, Christopher W.;Vogel, Heiko
植物与昆虫之间的化学相互作用为在分子水平上研究物种间相互作用的进化提供了极好的机会。在这里，我们调查的分子进化事件，产生了一种新的解毒酶（腈特异蛋白[NSP]）的蝴蝶家族粉蝶科，以前确定为共同进化的关键创新。通过生成和测序表达序列标签、基因组文库和筛选数据库，我们发现NSP是昆虫特异性基因家族的一员，我们将其表征并命名为NSP样基因家族。成员由可变串联重复序列组成，在肠道表达，并在昆虫纲中发现，它们在动态的、持续的出生-死亡过程中进化。在鳞翅目昆虫中，存在多个单结构域主要变应原基因拷贝，并通过串联重复产生。多个结构域基因仅在以芸苔为食的粉蝶科蝴蝶中发现，其中一个是NSP，另一个称为主要过敏原（MA）。分析表明，NSP和它的paraminoma有一个独特的单域进化起源，是由基因内的结构域复制，然后串联全基因复制。重复随后经历了一段时间的放松约束，然后增加约束，也许后neofunctionalization。NSP及其直系同源物MA仍在经历着高速率的变化，反映了与已知的NSP在植物-昆虫相互作用中的作用相一致的动态进化。我们的研究结果提供了直接的证据，假设基因复制是物种形成和适应的驱动力之一，表明内和全基因串联重复是一个强大的力量进化适应的基础。
Chemical interactions between plants and their insect herbivores provide an excellent opportunity to study the evolution of species interactions on a molecular level. Here, we investigate the molecular evolutionary events that gave rise to a novel detoxifying enzyme (nitrile-specifier protein [NSP]) in the butterfly family Pieridae, previously identified as a coevolutionary key innovation. By generating and sequencing expressed sequence tags, genomic libraries, and screening databases we found NSP to be a member of an insect-specific gene family, which we characterized and named the NSP-like gene family. Members consist of variable tandem repeats, are gut expressed, and are found across Insecta evolving in a dynamic, ongoing birth-death process. In the Lepidoptera, multiple copies of single-domain major allergen genes are present and originate via tandem duplications. Multiple domain genes are found solely within the brassicaceous-feeding Pieridae butterflies, one of them being NSP and another called major allergen (MA). Analyses suggest that NSP and its paralog MA have a unique single-domain evolutionary origin, being formed by intragenic domain duplication followed by tandem whole-gene duplication. Duplicates subsequently experienced a period of relaxed constraint followed by an increase in constraint, perhaps after neofunctionalization. NSP and its ortholog MA are still experiencing high rates of change, reflecting a dynamic evolution consistent with the known role of NSP in plant-insect interactions. Our results provide direct evidence to the hypothesis that gene duplication is one of the driving forces for speciation and adaptation, showing that both within- and whole-gene tandem duplications are a powerful force underlying evolutionary adaptation.