Our understanding of how the first mammalian cell lineages arise has been shaped largely by studies of the preimplantation mouse embryo. Painstaking work over many decades has begun to reveal how a single totipotent cell is transformed into a multilayered structure representing the foundations of the body plan. Here, we review how the first lineage decision is initiated by epigenetic regulation but consolidated by the integration of morphological features and transcription factor activity. The establishment of pluripotent and multipotent stem cell lines has enabled deeper analysis of molecular and epigenetic regulation of cell fate decisions. The capability to assemble these stem cells into artificial embryos is an exciting new avenue of research that offers a long-awaited window into cell fate specification in the human embryo. Together, these approaches are poised to profoundly increase our understanding of how the first lineage decisions are made during mammalian embryonic development.

中文翻译：

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体内和体外第一个哺乳动物细胞谱系的规范。

我们对第一个哺乳动物细胞谱系如何产生的理解主要是通过对植入前小鼠胚胎的研究而形成的。数十年来的艰苦工作已经开始揭示单个全能细胞如何转变为代表身体计划基础的多层结构。在这里，我们回顾了第一个谱系决定是如何由表观遗传调控引发的，但如何通过形态特征和转录因子活性的整合来巩固。多能和多能干细胞系的建立使得能够更深入地分析细胞命运决定的分子和表观遗传调控。将这些干细胞组装成人造胚胎的能力是一个令人兴奋的新研究途径，它为人类胚胎中的细胞命运规范提供了期待已久的窗口。一起，