Departments of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, USA.
Trends Neurosci. 2018 Dec;41(12):925-937. doi: 10.1016/j.tins.2018.07.005. Epub 2018 Aug 8.
The benefits of diploidy are considered to involve masking partially recessive mutations and increasing genetic diversity. Here, we review new studies showing evidence for diverse allele-specific expression and epigenetic states in mammalian brain cells, which suggest that diploidy expands the landscape of gene regulatory and expression programs in cells. Allele-specific expression has been thought to be restricted to a few specific classes of genes. However, new studies show novel genomic imprinting effects that are brain-region-, cell-type- and age-dependent. In addition, novel forms of random monoallelic expression that impact many autosomal genes have been described in vitro and in vivo. We discuss the implications for understanding the benefits of diploidy, and the mechanisms shaping brain development, function, and disease.
二倍体的优势被认为包括掩盖部分隐性突变和增加遗传多样性。在这里，我们回顾了新的研究，这些研究表明哺乳动物脑细胞中存在多种等位基因特异性表达和表观遗传状态，这表明二倍体扩展了细胞中基因调控和表达程序的景观。等位基因特异性表达被认为仅限于少数特定类别的基因。然而，新的研究显示了新的基因组印迹效应，这些效应依赖于脑区、细胞类型和年龄。此外，在体外和体内描述了影响许多常染色体基因的新型随机单等位基因表达形式。我们讨论了理解二倍体优势的意义，以及塑造大脑发育、功能和疾病的机制。
