Effects of chemical contaminants on genetic diversity in natural populations: Implications for biomonitoring and ecotoxicology

Department of Wildlife and Fisheries Sciences, Texas A&M University, 77843, College Station, TX 77843, USA.
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis (Impact Factor: 4.44). 08/2000; 463(1):33-51. DOI: 10.1016/S1383-5742(00)00004-1
Source: PubMed

ABSTRACT The conservation of genetic diversity has emerged as one of the central issues in conservation biology. Although researchers in the areas of evolutionary biology, population management, and conservation biology routinely investigate genetic variability in natural populations, only a handful of studies have addressed the effects of chemical contamination on population genetics. Chemical contamination can cause population reduction by the effects of somatic and heritable mutations, as well as non-genetic modes of toxicity. Stochastic processes in small populations, increased mutation load, and the phenomenon of mutational meltdown are compounding factors that cause reduced fitness and accelerate the process of population extirpation. Although the original damage caused by chemical contaminants is at the molecular level, there are emergent effects at the level of populations, such as the loss of genetic diversity, that are not predictable based solely on knowledge of the mechanism of toxicity of the chemical contaminants. Therefore, the study of evolutionary toxicology, which encompasses the population-genetic effects of environmental contaminants, should be an important focus of ecotoxicology. This paper reviews the issues surrounding the genetic effects of pollution, summarizes the technical approaches that can be used to address these issues, and provides examples of studies that have addressed some of them.

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Available from: John Bickham, Aug 21, 2015
    • "Pollution effects on organisms can imply consequences at the population level to varying degrees, from changes in population dynamics or genetic diversity (Bickham et al., 2000; Belfiore and Anderson, 2001), to the local extinction of a population (Gibbs and Bryan, 1996). Because biological communities are formed by multiple species interacting with each other, such impacts on populations can have implications for whole communities. "
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    ABSTRACT: Borja, A., J. Bremner, I. Muxika, J.G. Rodríguez, 2015. Chapter 14: Biological responses at supraindividual levels. In: Aquatic ecotoxicology: Advancing tools for dealing with emerging risks. Eds. C. Amiard-Triquet, J-C. Amiard, C. Mouneyrac, Academic Press, Elsevier, p. 333-354.
    Aquatic ecotoxicology: Advancing tools for dealing with emerging risks, Edited by C. Amiard-Triquet, J-C. Amiard, C. Mouneyrac, 07/2015: chapter Chapter 14: Biological responses at supraindividual levels: pages 333-354.; Academic Press, Elsevier.
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    • "One of the greatest challenges in evolutionary ecotoxicology lies in the ability to separate genetic diversity created by natural environmental factors that differ between habitats from genetic diversity caused by anthropogenic impacts, such as contamination (Hoffmann and Willi, 2008). In other words, to establish causality between contamination pressure and changes in genetic diversity in field populations (Bickham et al., 2000; DiBattista, 2008; van Straalen and Timmermans, 2002). It is generally argued that diversity within a given population of a species is important to uphold the fitness of the population (van Straalen and Timmermans, 2002), in parallel to biodiversity within communities that contributes to the sustainability and function of ecosystems (Naeem and Li, 1997; Rohr et al., 2006). "
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    • "Pollution in general may provoke rapid genetic changes in exposed populations at different time scale (Medina et al., 2007). Numerous studies demonstrated the role of heavy metals in selection for or against specific allozymic variants in various species (Moraga and Tanguy, 2000; Ma et al., 2000; Bickham et al., 2000; Belfiore and Anderson, 2001 for review). Quite often, local effluents of heavy metals create patches of altered habitats likely to promote diversifying selection in populations of benthic invertebrates (Lavie and Nevo, 1982; Nevo et al., 1984; Nevo, 2001) in a few generations following theoretical predictions of Hedrick (1986) about the action of selection in heterogeneous environments. "
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    ABSTRACT: Hydrothermal vent mussels belonging to the genus Bathymodiolus dominate communities at hydrothermal sites of the Mid-Atlantic Ridge. The mussel Bathymodiolus azoricus harbors thiotrophic and methanotrophic symbiotic bacteria in its gills and evolves in naturally highly metal contaminated environments. In the context of investigations on metal tolerance/effect in B. azoricus, we focused our work on the short-term adaptive response (15 days) of mussels to different metals exposure at a molecular level using metal concentrations chosen to mimic natural situations at three vents sites. The expression of a set of 38 genes involved in different steps of the metal uptake, detoxication and various metabolisms was analysed by qPCR. Mussels were also genotyped at 10 enzyme loci to explore the relationships among natural genetic variation and gene expression. Relation between symbiont content (both sulfur-oxidizing and methanogen bacteria) and gene expression was also analysed. Our study demonstrated the influence of metal cocktail composition and time exposure on the transcriptome regulation with a specific pattern of regulation observed for the three metal cocktail tested. We also evidenced the significant influence of some specific Pgm genotype on the global gene expression in our experimental populations and a general trend of a higher gene expression in individuals carrying a high symbiont content.
    Marine Genomics 12/2014; 21. DOI:10.1016/j.margen.2014.11.010 · 1.97 Impact Factor
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