Comments |
P.649 left column 2nd paragraph: "In the genome of many eukaryotes, cytosine residues are covalently modified by the addition of a methyl group preferentially, but not exclusively, at the sequence CpG. In mammals, 60%–90% of CpG sites are methylated, and most of the remaining unmethylated residues are clustered in CpG islands within functional gene promoters. Changes in methylation status can result in profound changes in gene expression, mostly in which methylation correlates with an inactive transcriptional status." |