Chemical modification of nucleotide bases in DNA provides one mechanism for conveying information in addition to the genetic code. 5-methylcytosine (5mC) represents the most common chemically modified base in eukaryotic genomes. Sometimes referred to simply as DNA methylation, in eukaryotes 5mC is most prevalent at CpG dinucleotides and is frequently associated with transcriptional repression of transposable elements. However, 5mC levels and distributions are variable across phylogenies, and emerging evidence suggests that the functions of DNA methylation may be more diverse and complex than was previously appreciated. We summarize the current understanding of DNA methylation profiles and functions in different eukaryotic lineages.

中文翻译：

---

DNA甲基化：真核生物共有和不同的特征。

除遗传密码外，DNA中核苷酸碱基的化学修饰还提供了一种传递信息的机制。5-甲基胞嘧啶（5mC）代表真核生物基因组中最常见的化学修饰碱基。在真核生物中，有时有时简称为DNA甲基化5mC在CpG二核苷酸中最为普遍，并经常与转座因子的转录抑制有关。但是，5mC的水平和分布在系统发育上是可变的，并且新出现的证据表明，DNA甲基化的功能可能比以前所认识的更加多样化和复杂。我们总结了目前在不同的真核细胞谱系中对DNA甲基化概况和功能的了解。