Mechanistic Basis of Resistance to PCBs in Atlantic Tomcod from the Hudson River

Department of Environmental Medicine, New York University School of Medicine,Tuxedo, NY 10987, USA.
Science (Impact Factor: 33.61). 02/2011; 331(6022):1322-5. DOI: 10.1126/science.1197296
Source: PubMed


The mechanistic basis of resistance of vertebrate populations to contaminants, including Atlantic tomcod from the Hudson River
(HR) to polychlorinated biphenyls (PCBs), is unknown. HR tomcod exhibited variants in the aryl hydrocarbon receptor 2 (AHR2)
that were nearly absent elsewhere. In ligand-binding assays, AHR2-1 protein (common in the HR) was impaired as compared to
widespread AHR2-2 in binding TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and in driving expression in reporter gene assays in AHR-deficient cells treated with TCDD or PCB126. We identified
a six-base deletion in AHR2 as the basis of resistance and suggest that the HR population has undergone rapid evolution, probably
due to contaminant exposure. This mechanistic basis of resistance in a vertebrate population provides evidence of evolutionary
change due to selective pressure at a single locus.

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Available from: Nirmal K Roy, Mar 06, 2014
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    • "In addition, PCBs are persistent enough to remain in the environment for enough time such that many generations of tomcod were exposed to the stress of pollution. Therefore, it seems that when a beneficial mutant allele is available in the populations originally exposed to the contaminants, as in the Atlantic tomcod, novel selective pressures can allow for the rapid fixation of this trait and for the success of populations that would normally collapse under these extreme anthropogenic selective pressures (Wirgin et al. 2011 "
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    • "Such mechanisms (i.e. altered receptor/accessory protein interactions) would be in accordance with that described for DL PCB specific tolerance in the PCB resistant tomcod (Microgadus tomcod) found in the Hudson River (Wirgin et al., 2011). Notably, AhR variants found in sensitive versus tolerant "
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