Some evolutionary consequences of the molecular recombination process

Leslie, John F.; Watt, Ward B.

doi:10.1016/0168-9525(86)90271-4

Cited by 5 publications

(2 citation statements)

References 26 publications

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“…Resistance is more likely to develop owing to emigration (gene flow) from pre-existing resistant populations (Pasteur & Raymond 1996;Futuyma 1998). Between-population gene flow and the resulting recombination, which increases genetic variation, are considered to be primary mechanisms for the development and spread of chemical resistance in wild populations (Leslie & Watt 1986). Recombination is also more frequent, thus, more likely, than de novo point mutation: King & Jukes (1969) estimated the substitution (mutation) rate at between 10 28 and 10 29 per codon per generation, whereas the crossing-over frequency (recombination) between two existing mutations in acetylcholine esterase has been shown to reach 10 25 (in Drosophila; Nagoshi & Gelbart 1987).…”

Section: The Genetic Basis For Chemical Resistancementioning

confidence: 99%

Genetic variation, inbreeding and chemical exposure—combined effects in wildlife and critical considerations for ecotoxicology

Brown

Hosken

Balloux

et al. 2009

Phil. Trans. R. Soc. B

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Exposure to environmental chemicals can have negative consequences for wildlife and even cause localized population extinctions. Resistance to chemical stress, however, can evolve and the mechanisms include desensitized target sites, reduced chemical uptake and increased metabolic detoxification and sequestration. Chemical resistance in wildlife populations can also arise independently of exposure and may be spread by gene flow between populations. Inbreeding-matings between closely related individuals-can have negative fitness consequences for natural populations, and there is evidence of inbreeding depression in many wildlife populations. In some cases, reduced fitness in inbred populations has been shown to be exacerbated under chemical stress. In chemical testing, both inbred and outbred laboratory animals are used and for human safety assessments, isogenic strains (virtual clones) of mice and rats are often employed that reduce response variation, the number of animals used and associated costs. In contrast, for environmental risk assessment, strains of animals are often used that have been selectively bred to maintain heterozygosity, with the assumption that they are better able to predict adverse effects in wild, genetically variable, animals. This may not necessarily be the case however, as one outbred strain may not be representative of another or of a wild population. In this paper, we critically discuss relationships between genetic variation, inbreeding and chemical effects with the intention of seeking to support more effective chemical testing for the protection of wildlife.

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Section: The Genetic Basis For Chemical Resistancementioning

confidence: 99%

Genetic variation, inbreeding and chemical exposure—combined effects in wildlife and critical considerations for ecotoxicology

Brown

Hosken

Balloux

et al. 2009

Phil. Trans. R. Soc. B

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show abstract

“…Intragenic recombination is thought to have important consequences for population and evolutionary genetics, mainly by increasing the number and frequency of different alleles (26). Although there is no evidence for a strict relationship between resistance and fitness cost, the insecticides Finally, the existence of several point mutations and the occurrence of intracistronic recombinations between the mutations have practical consequences in resistance-management programs.…”

mentioning

confidence: 99%

Resistance-associated point mutations in insecticide-insensitive acetylcholinesterase.

Mutero¹,

Pralavorio²,

Bride³

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

384

268

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Extensive utilization of pesticides against insects provides us with a good model for studying the adaptation of a eukaryotic genome to a strong selective pressure. One meanism ofresistance is the alteration ofacetyichoinesterase (EC 3.1.1.7), the molecular target for organophosphates and carbamates. Here, we report the sequence analysis of the Ace gene in several resistant field strains of Drosophila melanogaster. This analysis resulted in the identification of five point mutations associated with reduced sensitivities to insecticides. In some cases, several of these mutations were found to be combined in the same protein, leading to different resistance patterns. Our results suggest that recombination between resistant alleles preexisting in natural populations is a mechanism by which insects rapidly adapt to new selective pressures.Although insecticide resistance is an important agricultural problem, this phenomenon also provides a good model for studying adaptation of eukaryotes to a toxic environment. Resistance to insecticides results from three main mechanisms: reduction in the insecticide penetration; increased metabolization of the insecticide by esterases, mixedfunction oxidases, or glutathione transferases; and modification of the insecticide target.

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Emergence of Complex Haplotypes from Microevolutionary Variation in Sequence and Structure of Colias Phosphoglucose Isomerase

et al. 2009

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A molecular evolutionary explanation of natural genetic variation requires analysis of specific variants' evolutionary dynamics. To pursue this for phosphoglucose isomerase (PGI) of Colias butterflies, whose polymorphism is maintained by strong natural selection, we assembled a large data set of wild haplotypes, highly variable at the amino acid and DNA levels. The most common electrophoretic, i.e., charge macrostate, allele class, 3, is conserved in its pattern of charged amino acid residues. The next most common macrostate, 4, has multiple patterns of charge, i.e., microstates, while less common (1, 2, 5, 6) macrostates are very diverse. Macrostate 4 shows significant linkage disequilibrium (LD) among its variants, especially for two groups of five haplotypes each. We find extensive intragenic recombination among all haplotypes except the two high-LD groups of macrostate 4, which display none. Phyletic relations among haplotypes are largely reticulate, again except for the high-LD groups of macrostate 4, which form clades with strong bootstrap support. Charge-changing and linked charge-neutral amino acid variants occur in diverse parts of PGI's sequence. Homology-based modeling of PGI's structure shows that these regions are related spatially in ways suggesting functional interaction. The high-LD groups of macrostate 4 display parallel amino acid variation in these regions. This pattern of haplotype clades with high LD among multiple varying sites, emerging from chaotically recombining variation, may be a "signature" of refinement of complex adaptive sequences by recombination and selection. It should be tested further in this study system and others as a possibly general feature of the evolution of living complexity.

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Some evolutionary consequences of the molecular recombination process

Cited by 5 publications

References 26 publications

Genetic variation, inbreeding and chemical exposure—combined effects in wildlife and critical considerations for ecotoxicology

Genetic variation, inbreeding and chemical exposure—combined effects in wildlife and critical considerations for ecotoxicology

Resistance-associated point mutations in insecticide-insensitive acetylcholinesterase.

Emergence of Complex Haplotypes from Microevolutionary Variation in Sequence and Structure of Colias Phosphoglucose Isomerase

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