title: Global cytosine methylation in Daphnia magna depends on genotype, environment, and their interaction.
abstract: The authors characterized global cytosine methylation levels in 2 different genotypes of the ecotoxicological model organism Daphnia magna after exposure to a wide array of biotic and abiotic environmental stressors. The present study aimed to improve the authors' understanding of the role of cytosine methylation in the organism's response to environmental conditions. The authors observed a significant genotype effect, an environment effect, and a genotype × environment effect. In particular, global cytosine methylation levels were significantly altered after exposure to Triops predation cues, Microcystis, and sodium chloride compared with control conditions. Significant differences between the 2 genotypes were observed when animals were exposed to Triops predation cues, Microcystis, Cryptomonas, and sodium chloride. Despite the low global methylation rate under control conditions (0.49-0.52%), global cytosine methylation levels upon exposure to Triops demonstrated a 5-fold difference between the genotypes (0.21% vs 1.02%). No effects were found in response to arsenic, cadmium, fish, lead, pH of 5.5, pH of 8, temperature, hypoxia, and white fat cell disease. The authors' results point to the potential role of epigenetic effects under changing environmental conditions such as predation (i.e., Triops), diet (i.e., Cryptomonas and Microcystis), and salinity. The results of the present study indicate that, despite global cytosine methylation levels being low, epigenetic effects may be important in environmental studies on Daphnia.
authors: Laboratory for Environmental Toxicology and Aquatic Ecology (GhEnToxLab), Ghent University, Ghent, Belgium.
authors: Jana
authors: J
authors: Asselman
authors: Dieter I M
authors: DI
authors: De Coninck
authors: Michiel B
authors: MB
authors: Vandegehuchte
authors: Mieke
authors: M
authors: Jansen
authors: Ellen
authors: E
authors: Decaestecker
authors: Luc
authors: L
authors: De Meester
authors: Julie
authors: J
authors: Vanden Bussche
authors: Lynn
authors: L
authors: Vanhaecke
authors: Colin R
authors: CR
authors: Janssen
authors: Karel A C
authors: KA
authors: De Schamphelaere
mesh_terms: D000818:Animals; D002104:Cadmium / Q000737:chemistry / Q000633:toxicity; D003445:Crustacea / Q000378:metabolism; D003596:Cytosine / Q000737:chemistry / Q000378:metabolism*; D019175:DNA Methylation; D003621:Daphnia / Q000235:genetics* / Q000378:metabolism; D004777:Environment; D057890:Epigenomics; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D046931:Microcystis / Q000378:metabolism; D011235:Predatory Behavior; D012965:Sodium Chloride / Q000737:chemistry; D013312:Stress, Physiological; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D012965:Sodium Chloride; D003596:Cytosine
keywords: Aquatic invertebrate; Cytosine methylation; Ecotoxicology; Environmental toxicology; Epigenetics