Genomic imprinting is the monoallelic expression of a gene based on parent of origin and is a consequence of differential epigenetic marking between the male and female germlines. Canonically, genomic imprinting is mediated by allelic DNA methylation. However, recently it has been shown that maternal H3K27me3 can result in DNA methylation-independent imprinting, termed “noncanonical imprinting.” In this review, we compare and contrast what is currently known about the underlying mechanisms, the role of endogenous retroviral elements, and the conservation of canonical and noncanonical genomic imprinting.

中文翻译：

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规范和非规范基因组印记的特征和机制


基因组印记是基于起源亲本的基因的单等位基因表达，是雄性和雌性种系之间差异表观遗传标记的结果。通常，基因组印记是由等位基因 DNA 甲基化介导的。然而，最近的研究表明，母体 H3K27me3 可以导致不依赖于 DNA 甲基化的印记，称为“非规范印记”。在这篇综述中，我们比较和对比了目前已知的潜在机制、内源性逆转录病毒元件的作用以及规范和非规范基因组印记的保守性。