Genetics of Radionuclide-Contaminated Mosquitofish Populations and Homology Between Gambusia Affinis and G. Holbrooki

Abstract

Abstract-The effects of radionuclide contamination on genetic structure of eastern mosquitofish (Gambusia holbrooki) populations from the U.S. Department of Energy's Savannah River Site (SRS) were investigated to develop methods of assessing ecological risk of chronic exposures to xenobiotics. Fish from two contaminated and two reference sites were examined by the randomly amplified polymorphic DNA (RAPD) technique, which revealed that the frequency of three markers was greater in the contaminated than the reference sites and that the frequency of two markers was greater in the reference than in the contaminated sites. A previous study examined populations of western mosquitofish (G. affinis) from the Oak Ridge National Laboratory (ORNL) and found that certain RAPD markers were present in radionuclide-contaminated ORNL populations at a higher frequency than in reference populations. The ''contaminant-indicative'' markers observed in the SRS populations were the same size and amplified by the same polymerase chain reaction primers used in the ORNL study. Southern blot analysis revealed that the SRS G. holbrooki contaminantindicative markers were homologous to the ORNL G. affinis contaminant-indicative markers. The observation that two species show similar patterns of band frequency shifts at two separate localities is consistent with the hypothesis that these DNA markers may originate from genetic elements that provide a selective advantage in contaminated habitats. Thus, the methodology used in these studies may prove to be useful to indicate population-level effects of environmental contamination.

PCR based detection of furadan genotoxicity effects in rohu (Labeo rohita) fingerlings

“…However, if the conditions of the assays are properly optimized these inconveniences can be solved (Theodorakis et al 1998;Becerril et al 1999). By optimizing the RAPD conditions, cloning the PCR products and further sequencing the products may be useful in analyzing the nature and mode of action of the genotoxicants (Theodorakis et al 1998;Becerril et al 1999). The present investigation though could detect the pesticide induced DNA damage by RAPD-PCR; still it needs further studies for its regular use as a tool in the detection of alterations in DNA sequence due to the genotoxicants.…”

Effects of acid mine drainage on the genetic diversity and structure of a natural population of Daphnia longispina

“…Furthermore, a consistent relationship between glucose-6-phosphate isomerase genotypes and response to several environmental stressors, including metals, has been shown (review in Tatara et al, 2001). Contaminant indicative bands, derived from RAPD analysis, were also found in populations inhabiting radionuclide-contaminated lakes and in artificial selection experiments by the same contaminants (Theodorakis et al, 1998(Theodorakis et al, , 1999. As the former authors pointed out, it is possible that these bands could not be directly related to the toxic mode of action, being contaminant-specific or always indicative of contaminant exposure, given that they were a result of random whole genome surveys and could have appeared only due to the probabilistic nature of both methodologies (i.e., AFLP and RAPD).…”

Genetic diversity of the major histocompatibility complex of cotton rats (Sigmodon hispidus) inhabiting an oil refinery complex

“…Randomly amplified polymorphic DNA have greater potential as markers of effect because many loci throughout the genome can be randomly surveyed. One disadvantage to using RAPDs is that the functions of these loci are not known prior to molecular characterization [11]. Because of the immensity of the genome, it is not likely that many of these randomly sampled loci would be directly influenced by contaminant‐induced selection.…”