Insecticide resistance in the mosquito Culex pipiens:: what have we learned about adaptation?
Insecticide resistance in the mosquito Culex pipiens:: what have we learned about adaptation?
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DOI：
10.1023/a:1013300108134
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发表时间：
2001-11-01
期刊：
影响因子：
1.5
通讯作者：
Chevillon, C
中科院分区：
文献类型：
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作者：
Raymond, M;Berticat, C;Chevillon, C
淡色库蚊对有机磷(OP)杀虫剂的抗性研究已有近30年的历史。这个微观进化的例子已经被彻底研究，作为一个机会，准确地评估新的适应表型和相关的遗传变化。一个显著的特点是，OP抗性是通过很少的基因实现的，而且这些基因通常有很大的影响。产生这种抗性基因的分子事件是复杂的(例如，基因扩增、基因调控)，可能解释它们从头发生的频率较低。相比之下，迁徙是一种频繁的事件，包括遥远人口之间的被动交通。这在突变和迁移之间产生了复杂的相互作用，并促进了抗性等位基因之间的竞争。当每个基因产物的精确生理作用都相当清楚时，就有可能理解所观察到的显性水平或上位性类型。然而，很难预先预测抗性基因将如何相互作用，现在就断言这是否可能还为时过早。这些抗性基因的成本很高，而且不同的抗性基因的成本是不同的。通常认为，由于后续具有修饰效应的突变，初始适应度成本将逐渐下降。在本例中，在一个抗性基因座上出现了特定的修饰物(基因重复)，而在另一个抗病基因座上，成本的降低是由等位基因替换驱动的，显然不是通过选择修饰物来驱动的。
Resistance to organophosphate (OP) insecticide in the mosquito Culex pipiens has been studied for ca. 30 years. This example of micro-evolution has been thoroughly investigated as an opportunity to assess precisely both the new adapted phenotypes and the associated genetic changes. A notable feature is that OP resistance is achieved with few genes, and these genes have generally large effects. The molecular events generating such resistance genes are complex (e.g., gene amplification, gene regulation) potentially explaining their low frequency of de novo occurrence. In contrast, migration is a frequent event, including passive transportation between distant populations. This generates a complex interaction between mutations and migration, and promotes competition among resistance alleles. When the precise physiological action of each gene product is rather well known, it is possible to understand the dominance level or the type of epistasis observed. It is however difficult to predict a priori how resistance genes will interact, and it is too early to state whether or not this will be ever possible. These resistance genes are costly, and the cost is variable among them. It is usually believed that the initial fitness cost would gradually decrease due to subsequent mutations with a modifier effect. In the present example, a particular modifier occurred (a gene duplication) at one resistance locus, whereas at the other one reduction of cost is driven by allele replacement and apparently not by selection of modifiers.