Est-2 and Est-3 polymorphisms in Culex pipiens L. from southern France in relation to organophosphate resistance

Pasteur, Nicole; Sinègre, G.; Gabinaud, A.

doi:10.1007/bf00484622

Cited by 48 publications

(33 citation statements)

References 13 publications

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“…Mosquitoes with known overproduced esterases were run in each gel as controls: esterase Al (strain BARRIOL which replaces the S54 strain of Pasteur et al 1981b), esterases A4-B4 (strain VIM, Poirie et al 1992), and esterases A2-B2 (strain SELAX, Wirth et al 1990). Because of the fast staining procedure needed to score highly active overproduced esterases, esterases B with normal activity, such as the Est-2°·64 allele, were only noted when there was no possible ambiguity occurs in the referenced BARRIOL strain).…”

Section: Methodsmentioning

confidence: 99%

POPULATION STRUCTURE AND DYNAMICS OF SELECTED GENES IN THE MOSQUITOCULEX PIPIENS

et al. 1995

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Abstract.-To determine the outcome of the combined effects of gene flow, genetic drift, and selection on the evolution of insecticide-resistance genes in the mosquito Culex pipiens, samples were collected along three transects crossing treated and non treated areas in northern Spain and southern France. Electrophoretic polymorphisms of five presumably neutral genes disclosed that differentiation among samples was low, and that both Wright F-statistics and Slatkin private-alleles methods provided a high estimate for Nm. In contrast, there was a strong differentiation in the distribution of resistance genes closely associated with insecticide treatments. These divergent situations are explained in relation to both the very recent origin of some resistance genes that are still localized geographically (A2-B2 and Cl), and the high fitness cost of the older and ubiquitous ones in nontreated areas (AI, A4-B4, and Ace"),

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Section: Methodsmentioning

confidence: 99%

POPULATION STRUCTURE AND DYNAMICS OF SELECTED GENES IN THE MOSQUITOCULEX PIPIENS

et al. 1995

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“…However, such resistance mechanisms are either absent in natural populations, or their contribution to OP resistance relatively minor compared to overproduced esterases or insensitive target (e.g., Pasteur & Sinègre, 1978;Pasteur, Sinègre & Gabinaud, 1981;Raymond et al, 1987), although this is not the case in Tunisia .…”

Section: Genetics Of Resistancementioning

confidence: 99%

Insecticide resistance in the mosquito Culex pipiens: What have we learned about adaptation?

Raymond

Berticat

Weill

et al. 2001

Microevolution Rate, Pattern, Process

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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.

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“…Methods ofElectrophoresis.-The only difference between the two methods of electrophoresis (de Stordeur 1976;Pasteur et al 1988) was that nonoverproduced esterases could also be visualized (in addition to overproduced esterases) with the method used for mosquitoes sampled before 1980 and therefore allowed genotypic characterisation (Pasteur and Sinegre 1975;Pasteur 1977;Pasteur et al 1981). Highly active esterases were revealed in the exact way in both protocols.…”

Section: Data Comparisonmentioning

confidence: 99%

“…The occurrence of organophosphorous (OP) resistance and OP-resistance genes in this area has already been described (Pasteur and Sinegre 1975;Pasteur et al 1981;Raymond et al 1986;Chevillon et al 1995). Basically, the first resistance gene (overproduced Al ester-443 444 THOMAS GUILLEMAUD ET AL.…”

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EVOLUTION OF RESISTANCE INCULEX PIPIENS: ALLELE REPLACEMENT AND CHANGING ENVIRONMENT

et al. 1998

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Abstract.-Fixation of adaptive mutations in populations is often constrained by pleiotropic fitness costs. The evolutionary pathways that compensate such fitness disadvantages are either the occurrence of modifier genes or replacement of the adaptive allele by less costly ones. In this context, 23 years of evolution of insecticide resistance genes in the mosquito Culex pipiens from southern France are analyzed. The aim of this study is to answer the following points. Is there a fitness cost associated with these resistance genes in natural populations? Does evolution proceed through allele replacement or through selection of modifiers? And finally, how do environmental changes affect the evolution of resistance genes? Samples from the same transect, crossing the boundary between an insecticide-treated and a nontreated area, are analyzed. Clinal analyses indicate a variable fitness cost among the resistance genes and show that allele replacement has been the primary mechanism of resistance evolution in this area. It is also shown that replacement was probably due to environmental changes corresponding to modification in pesticide-treatment intensity.

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Est-2 and Est-3 polymorphisms in Culex pipiens L. from southern France in relation to organophosphate resistance

Cited by 48 publications

References 13 publications

POPULATION STRUCTURE AND DYNAMICS OF SELECTED GENES IN THE MOSQUITOCULEX PIPIENS

POPULATION STRUCTURE AND DYNAMICS OF SELECTED GENES IN THE MOSQUITOCULEX PIPIENS

Insecticide resistance in the mosquito Culex pipiens: What have we learned about adaptation?

EVOLUTION OF RESISTANCE INCULEX PIPIENS: ALLELE REPLACEMENT AND CHANGING ENVIRONMENT

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