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Influence of tissue, age, and environmental quality on DNA methylation in Alligator mississippiensis

Authors :
Phillip M Wilkinson
John A. Bowden
Benjamin B. Parrott
Thomas R. Rainwater
John R. Kucklick
Louis J. Guillette
Jessica A. Cloy-McCoy
Satomi Kohno
Jacqueline T. Bangma
Matthew D. Hale
Source :
REPRODUCTION. 147:503-513
Publication Year :
2014
Publisher :
Bioscientifica, 2014.

Abstract

Epigenetic modifications are key mediators of the interactions between the environment and an organism's genome. DNA methylation represents the best-studied epigenetic modification to date and is known to play key roles in regulating transcriptional activity and promoting chromosome stability. Our laboratory has previously demonstrated the utility of the American alligator (Alligator mississippiensis) as a sentinel species to investigate the persistent effects of environmental contaminant exposure on reproductive health. Here, we incorporate a liquid chromatography–tandem mass spectrometry method to directly measure the total (global) proportion of 5-methyl-2′-deoxycytidine (5mdC) in ovarian and whole blood DNA from alligators. Global DNA methylation in ovaries was significantly elevated in comparison with that of whole blood. However, DNA methylation appeared similar in juvenile alligators reared under controlled laboratory conditions but originating from three sites with dissimilar environmental qualities, indicating an absence of detectable site-of-origin effects on persistent levels of global 5mdC content. Analyses of tissues across individuals revealed a surprising lack of correlation between global methylation levels in blood and ovary. In addition, global DNA methylation in blood samples from juvenile alligators was elevated compared with those from adults, suggesting that age, as observed in mammals, may negatively influence global DNA methylation levels in alligators. To our knowledge, this is the first study examining global levels of DNA methylation in the American alligator and provides a reference point for future studies examining the interplay of epigenetics and environmental factors in a long-lived sentinel species.

Details

ISSN :
17417899 and 14701626
Volume :
147
Database :
OpenAIRE
Journal :
REPRODUCTION
Accession number :
edsair.doi.dedup.....1ef6c782e6b20beee01d4e20b9a1eb54
Full Text :
https://doi.org/10.1530/rep-13-0498