By altering gene expression and creating paralogs, genomic amplifications represent a key component of short-term adaptive processes. In insects, the use of insecticides can select gene amplifications causing an increased expression of detoxification enzymes, supporting the usefulness of these DNA markers for monitoring the dynamics of resistance alleles in the field. In this context, the present study aims to characterise a genomic amplification event associated with resistance to organophosphate insecticides in the mosquito Aedes aegypti and to develop a molecular assay to monitor the associated resistance alleles in the field. An experimental evolution experiment using a composite population from Laos supported the association between the over-transcription of multiple contiguous carboxylesterase genes on chromosome 2 and resistance to multiple organophosphate insecticides. Combining whole genome sequencing and qPCR on specific genes confirmed the presence of a ~100 Kb amplification spanning at least five carboxylesterase genes at this locus with the co-existence of multiple structural duplication haplotypes. Field data confirmed their circulation in South-East Asia and revealed high copy number polymorphism among and within populations suggesting a trade-off between this resistance mechanism and associated fitness costs. A dual-colour multiplex TaqMan assay allowing the rapid detection and copy number quantification of this amplification event in Ae. aegypti was developed and validated on field populations. The routine use of this novel assay will improve the tracking of resistance alleles in this major arbovirus vector.

中文翻译：

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影响羧酸酯酶基因簇的基因组扩增赋予埃及伊蚊以有机磷酸酯抗性：从基因组鉴定到高通量野外检测

通过改变基因表达并创建旁系同源物，基因组扩增代表了短期适应性过程的关键组成部分。在昆虫中，使用杀虫剂可以选择基因扩增，从而增加解毒酶的表达，从而支持这些DNA标记物在田间监测抗性等位基因动态的有用性。在这种情况下，本研究旨在表征与埃及伊蚊（Aedes aegypti）对有机磷酸酯杀虫剂的抗性相关的基因组扩增事件，并开发一种分子检测方法来监测该领域的相关抗性等位基因。使用来自老挝的复合种群的实验进化实验支持2号染色体上多个连续羧酸酯酶基因的过度转录与对多种有机磷杀虫剂的抗性之间的关联。结合全基因组测序和特定基因的qPCR证实，在该基因座处存在至少100个Kb扩增，跨越至少五个羧酸酯酶基因，并存在多种结构重复单倍型。实地数据证实了它们在东南亚的流通，并揭示了种群之间和种群内部的高拷贝数多态性，表明在这种抵抗机制与相关适应性成本之间进行了权衡。一种双色多重TaqMan测定法，可以快速检测和扩增Ae中这种扩增事件的拷贝数。aegypti是在野外种群中开发并验证的。该新颖测定的常规使用将改善该主要虫媒病毒载体中抗性等位基因的追踪。