Pre-invasion history and demography shape the genetic variation in the insecticide resistance-related acetylcholinesterase 2 gene in the invasive Colorado potato beetleReportar como inadecuado

Pre-invasion history and demography shape the genetic variation in the insecticide resistance-related acetylcholinesterase 2 gene in the invasive Colorado potato beetle - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Evolutionary Biology

, 13:13

Speciation and evolutionary genetics


BackgroundInvasive pest species offers a unique opportunity to study the effects of genetic architecture, demography and selection on patterns of genetic variability. Invasive Colorado potato beetle Leptinotarsa decemlineata populations have experienced a rapid range expansion and intense selection by insecticides. By comparing native and invasive beetle populations, we studied the origins of organophosphate OP resistance-associated mutations in the acetylcholinesterase 2 AChE2 gene, and the role of selection and demography on its genetic variability.

ResultsAnalysis of three Mexican, two US and five European populations yielded a total of 49 haplotypes. Contrary to the expectations all genetic variability was associated with a point mutation linked to insecticide resistance S291G, this mutation was found in 100% of Mexican, 95% of US and 71% of European beetle sequences analysed. Only two susceptible haplotypes, genetically very differentiated, were found, one in US and one in Europe. The genetic variability at the AChE2 gene was compared with two other genes not directly affected by insecticide selection, diapause protein 1 and juvenile hormone esterase. All three genes showed reduction in genetic variability indicative of a population bottleneck associated with the invasion.

ConclusionsStochastic effects during invasion explain most of the observed patterns of genetic variability at the three genes investigated. The high frequency of the S291G mutation in the AChE2 gene among native populations suggests this mutation is the ancestral state and thus, either a pre-adaptation of the beetle for OP resistance or the AChE2 is not the major gene conferring OP resistance. The long historical association with host plant alkaloids together with recombination may have contributed to the high genetic variation at this locus. The genetic diversity in the AChE2 locus of the European beetles, in turn, strongly reflects founder effects followed by rapid invasion. Our results suggest that despite the long history of insecticide use in this species, demographic events together with pre-invasion history have been strongly influential in shaping the genetic diversity of the AChE2 gene in the invasive beetle populations.

KeywordsAcetylcholinesterase Diapause protein 1 Invasion biology Invasive species Juvenile hormone esterase Pesticide resistance Resistance evolution Selection Electronic supplementary materialThe online version of this article doi:10.1186-1471-2148-13-13 contains supplementary material, which is available to authorized users.

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Autor: Saija Piiroinen - Leena Lindström - Anne Lyytinen - Johanna Mappes - Yolanda H Chen - Victor Izzo - Alessandro Grapputo


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