Conserved and Divergent Patterns of DNA Methylation in Higher Vertebrates.

DNA methylation in the genome plays a fundamental role in the regulation of gene expression and is widespread in the genome of eukaryotic species. For example, in higher vertebrates, there is a"global" methylationpattern involving completemethylation of CpG sitesgenome-wide, except in promoter regions that are typically enriched for CpG dinucleotides, or so called "CpG islands" Here, we comprehensively examined and compared the distribution of CpG sites within tenmodel eukaryotic species and linked the observed patterns to the role of DNA methylation incontrollinggenetranscription. The analysis revealedtwodistinctbut conservedmethylation patterns for gene promoters in human and mouse genomes, involving geneswith distinct distributions of promoter CpGs and gene expression patterns. Comparative analysis with four other higher vertebrates revealed that the primary regulatory role of the DNA methylation system is highly conserved in higher vertebrates. [ABSTRACT FROM AUTHOR]