title: Evolutionary Consequences of DNA Methylation in a Basal Metazoan.
abstract: Gene body methylation (gbM) is an ancestral and widespread feature in Eukarya, yet its adaptive value and evolutionary implications remain unresolved. The occurrence of gbM within protein-coding sequences is particularly puzzling, because methylation causes cytosine hypermutability and hence is likely to produce deleterious amino acid substitutions. We investigate this enigma using an evolutionarily basal group of Metazoa, the stony corals (order Scleractinia, class Anthozoa, phylum Cnidaria). We show that patterns of coral gbM are similar to other invertebrate species, predicting wide and active transcription and slower sequence evolution. We also find a strong correlation between gbM and codon bias, resulting from systematic replacement of CpG bearing codons. We conclude that gbM has strong effects on codon evolution and speculate that this may influence establishment of optimal codons.
authors.affiliation: Institute for Cell and Molecular Biology, University of Texas grovesdixon@gmail.com.
authors.forename: Groves B
authors.initials: GB
authors.lastname: Dixon
authors.affiliation: Australian Institute of Marine Science, Townsville, QLD, Australia ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, Australia.
authors.forename: Line K
authors.initials: LK
authors.lastname: Bay
authors.affiliation: Department of Integrative Biology, University of Texas.
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Matz
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000235:genetics*; D005075:Biological Evolution; D003062:Codon; D003596:Cytosine / Q000378:metabolism; D019175:DNA Methylation; D019143:Evolution, Molecular; D020869:Gene Expression Profiling / Q000379:methods; D059645:Mutation Rate; D016366:Open Reading Frames; D010802:Phylogeny; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D003062:Codon; D003596:Cytosine
keywords: DNA methylation; codon bias; coral; gene body methylation; gene expression; substitution rate