title: Global DNA methylation loss associated with mercury contamination and aging in the American alligator (Alligator mississippiensis).
abstract: Mercury is a widespread environmental contaminant with exposures eliciting a well-documented catalog of adverse effects. Yet, knowledge regarding the underlying mechanisms by which mercury exposures are translated into biological effects remains incomplete. DNA methylation is an epigenetic modification that is sensitive to environmental cues, and alterations in DNA methylation at the global level are associated with a variety of diseases. Using a liquid chromatography tandem mass spectrometry-based (LC-MS/MS) approach, global DNA methylation levels were measured in red blood cells of 144 wild American alligators (Alligator mississippiensis) from 6 sites with variable levels of mercury contamination across Florida's north-south axis. Variation in mercury concentrations measured in whole blood was highly associated with location, allowing the comparison of global DNA methylation levels across different "treatments" of mercury. Global DNA methylation in alligators across all locations was weakly associated with increased mercury exposure. However, a much more robust relationship was observed in those animals sampled from locations more highly contaminated with mercury. Also, similar to other vertebrates, global DNA methylation appears to decline with age in alligators. The relationship between age-associated loss of global DNA methylation and varying mercury exposures was examined to reveal a potential interaction. These findings demonstrate that global DNA methylation levels are associated with mercury exposure, and give insights into interactions between contaminants, aging, and epigenetics.
authors.affiliation: National Institute of Standards and Technology, Chemical Sciences Division, Environmental Chemical Sciences Group, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States; Medical University of South Carolina, Marine Biomedicine and Environmental Sciences, 221 Fort Johnson Road, Charleston, SC 29412, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States. Electronic address: frances.nilsen@noaa.gov.
authors.forename: Frances M
authors.initials: FM
authors.lastname: Nilsen
authors.affiliation: Medical University of South Carolina, Marine Biomedicine and Environmental Sciences, 221 Fort Johnson Road, Charleston, SC 29412, United States; Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC 29403, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Benjamin B
authors.initials: BB
authors.lastname: Parrott
authors.affiliation: National Institute of Standards and Technology, Chemical Sciences Division, Environmental Chemical Sciences Group, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: John A
authors.initials: JA
authors.lastname: Bowden
authors.affiliation: National Institute of Standards and Technology, Chemical Sciences Division, Environmental Chemical Sciences Group, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Brittany L
authors.initials: BL
authors.lastname: Kassim
authors.affiliation: Medical University of South Carolina, Marine Biomedicine and Environmental Sciences, 221 Fort Johnson Road, Charleston, SC 29412, United States; Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC 29403, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Somerville
authors.affiliation: Medical University of South Carolina, Marine Biomedicine and Environmental Sciences, 221 Fort Johnson Road, Charleston, SC 29412, United States; Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC 29403, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Bryan
authors.affiliation: National Institute of Standards and Technology, Chemical Sciences Division, Environmental Chemical Sciences Group, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Colleen E
authors.initials: CE
authors.lastname: Bryan
authors.affiliation: Florida Fish and Wildlife Conservation Commission, 601 W. Woodward Ave, Eustis, FL 32726, United States.
authors.forename: Ted R
authors.initials: TR
authors.lastname: Lange
authors.affiliation: Deseret Ranches- 13754 Deseret Lane, St. Cloud, Florida 34773-9381, United States.
authors.forename: J Patrick
authors.initials: JP
authors.lastname: Delaney
authors.affiliation: Florida Fish and Wildlife Conservation Commission, 601 W. Woodward Ave, Eustis, FL 32726, United States.
authors.forename: Arnold M
authors.initials: AM
authors.lastname: Brunell
authors.affiliation: National Institute of Standards and Technology, Chemical Sciences Division, Environmental Chemical Sciences Group, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Long
authors.affiliation: Medical University of South Carolina, Marine Biomedicine and Environmental Sciences, 221 Fort Johnson Road, Charleston, SC 29412, United States; Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC 29403, United States; Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, United States.
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Guillette
mesh_terms: D000375:Aging / Q000187:drug effects; D000489:Alligators and Crocodiles / Q000502:physiology*; D000818:Animals; D019175:DNA Methylation; D005431:Florida; D008628:Mercury / Q000378:metabolism / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: American alligator; DNA methylation; Deoxyribonucleoside; Environmental contaminants; Liquid chromatography; Mass spectrometry; Mercury