Evolutionary Toxicology: Population-Level Effects of Chronic Contaminant Exposure on the Marsh Frogs (Rana ridibunda) of Azerbaijan Cole W. Matson,1 Megan M. Lambert,1 Thomas J. McDonald,2 Robin L. Autenrieth,3 Kirby C. Donnelly,2,4 Arif Islamzadeh,5 Dmitri I. Politov,6 and John W. Bickham1 1Department of Wildlife and Fisheries Sciences, 2School of Rural Public Health, 3Department of Civil Engineering, and 4Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station, Texas, USA; 5Sumgayit Centre for Environmental Rehabilitation, Sumgayit, Azerbaijan; 6Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia Abstract We used molecular methods and population genetic analyses to study the effects of chronic contaminant exposure in marsh frogs from Sumgayit, Azerbaijan. Marsh frogs inhabiting wetlands in Sumgayit are exposed to complex mixtures of chemical contaminants, including petroleum products, pesticides, heavy metals, and many other industrial chemicals. Previous results documented elevated estimates of genetic damage in marsh frogs from the two most heavily contaminated sites. Based on mitochondrial DNA (mtDNA) control region sequence data, the Sumgayit region has reduced levels of genetic diversity, likely due to environmental degradation. The Sumgayit region also acts as an ecological sink, with levels of gene flow into the region exceeding gene flow out of the region. Additionally, localized mtDNA heteroplasmy and diversity patterns suggest that one of the most severely contaminated sites in Sumgayit is acting as a source of new mutations resulting from an increased mutation rate. This study provides an integrated method for assessing the cumulative population impacts of chronic contaminant exposure by studying both population genetic and evolutionary effects. Key words: Azerbaijan, complex mixtures, evolutionary toxicology, heteroplasmy, mutation rate, Rana ridibunda. Environ Health Perspect 114: 547-552 (2006) . doi:10.1289/ehp.8404 available via http://dx.doi.org/ [Online 15 December 2005] Address correspondence to C.W. Matson, Integrated Toxicology Program, Duke University, LSRC A346, Box 90328, Durham, NC 27708-0328 USA. Telephone: (919) 613-8056. Fax: (919) 668-1799. E-mail: matson@duke.edu We thank A.A. Mekhtiev and R. Kasimov (Karaev Institute of Physiology, Azerbaijan National Academy of Sciences) , for logistical support and T. Colborn, R.L. Honeycutt, G.T. Rowe, C.M. Somers, and J.K. Wickliffe for thoughtful review of the manuscript. This article has been modified from a chapter in the dissertation of C.W.M. ; the dissertation copyright is retained by the author. Funding was provided by the National Institute of Environmental Health Sciences, Superfund Basic Research Programs grant ES04917. The authors declare they have no competing financial interests. Received 14 June 2005 ; accepted 15 December 2005. The full version of this article is available for free in HTML or PDF formats. |