title: Gene Body Methylation Patterns in Daphnia Are Associated with Gene Family Size.
abstract: The relation between gene body methylation and gene function remains elusive. Yet, our understanding of this relationship can contribute significant knowledge on how and why organisms target specific gene bodies for methylation. Here, we studied gene body methylation patterns in two Daphnia species. We observed both highly methylated genes and genes devoid of methylation in a background of low global methylation levels. A small but highly significant number of genes was highly methylated in both species. Remarkably, functional analyses indicate that variation in methylation within and between Daphnia species is primarily targeted to small gene families whereas large gene families tend to lack variation. The degree of sequence similarity could not explain the observed pattern. Furthermore, a significant negative correlation between gene family size and the degree of methylation suggests that gene body methylation may help regulate gene family expansion and functional diversification of gene families leading to phenotypic variation.
authors.affiliation: Laboratory for Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University, Ghent, Belgium Department of Biological Sciences, University of Notre Dame jana.asselman@ugent.be.
authors.forename: Jana
authors.initials: J
authors.lastname: Asselman
authors.affiliation: Laboratory for Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University, Ghent, Belgium Laboratory of Pharmaceutical Biotechnology (labFBT), Ghent University, Ghent, Belgium.
authors.forename: Dieter I M
authors.initials: DI
authors.lastname: De Coninck
authors.affiliation: Department of Biological Sciences, University of Notre Dame Environmental Change Initiative, University of Notre Dame.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Pfrender
authors.affiliation: Laboratory for Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University, Ghent, Belgium.
authors.forename: Karel A C
authors.initials: KA
authors.lastname: De Schamphelaere
mesh_terms: D000818:Animals; D018899:CpG Islands; D004247:DNA / Q000235:genetics; D019175:DNA Methylation; D003621:Daphnia / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
chemical_list: D004247:DNA
keywords: DNA methylation; Daphnia; gene function