Identification of New Human Imprinted Genes: A Novel Approach

“印记”基因对人类正常生长和发育至关重要。我们几乎所有的基因都是成对出现的，每个基因对的一个拷贝继承自我们的母亲（母系），另一个来自我们的父亲（父系）。对于我们绝大多数的基因对来说，从每个父母那里继承的拷贝是平等表达的。然而，印记基因以来源特异性的方式表达。也就是说，基因是从母本或父本拷贝转录（读取）的，而不是两者，并且这些基因的表达在特定组织中可能不同。实现这种特殊类型的转录的机制被称为表观遗传。表观遗传标记，如DNA甲基化，通过使其无法进入细胞中的转录机制，基本上使基因沉默。印记基因通常在成对的两个亲本基因上具有相反的表观遗传标记，一个甲基化（沉默），另一个未甲基化（转录）。 这就是所谓的差异DNA甲基化。

"Imprinted" genes are critical for normal human growth and development. Almost all of our genes occur in pairs, with one copy of each gene pair inherited from our mother (maternal) and the other from our father (paternal). For the vast majority of our gene pairs, the copy inherited from each parent is expressed equally. However, imprinted genes are expressed in a parent of origin-specific manner. That is, the genes are transcribed (read) from either the maternal or paternal copy, not both, and the expression of these genes may differ in specific tissues. The mechanism by which this special type of transcription is achieved is termed epigenetic. Epigenetic marks, such as DNA methylation, essentially silence the gene by making it inaccessible to the transcription machinery in the cell. Imprinted genes typically have opposite epigenetic marks on the two parental genes in the pair, one methylated (silenced) and the other not methylated (transcribed). This is called differential DNA methylation.