During mouse embryonic development a mass of pluripotent epiblast tissue is transformed during gastrulation to generate the three definitive germ layers: endoderm, mesoderm, and ectoderm. During gastrulation, a spatiotemporally controlled sequence of events results in the generation of organ progenitors and positions them in a stereotypical fashion throughout the embryo. Key to the correct specification and differentiation of these cell fates is the establishment of an axial coordinate system along with the integration of multiple signals by individual epiblast cells to produce distinct outcomes. These signaling domains evolve as the anterior-posterior axis is established and the embryo grows in size. Gastrulation is initiated at the posteriorly positioned primitive streak, from which nascent mesoderm and endoderm progenitors ingress and begin to diversify. Advances in technology have facilitated the elaboration of landmark findings that originally described the epiblast fate map and signaling pathways required to execute those fates. Here we will discuss the current state of the field and reflect on how our understanding has shifted in recent years.

中文翻译：

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小鼠原肠胚形成：细胞命运的组织模式、规格和多样化的协调

在小鼠胚胎发育过程中，大量的多能外胚层组织在原肠胚形成过程中被转化以产生三个最终的胚层：内胚层、中胚层和外胚层。在原肠胚形成过程中，一系列时空控制的事件导致器官祖细胞的产生，并将它们以一种刻板的方式定位在整个胚胎中。正确规范和区分这些细胞命运的关键是建立一个轴向坐标系，同时整合单个外胚层细胞的多个信号以产生不同的结果。这些信号域随着前后轴的建立和胚胎大小的增长而进化。原肠位于后方的原条处开始形成原肠，新生的中胚层和内胚层祖细胞从中进入并开始多样化。技术进步促进了具有里程碑意义的发现的制定，这些发现最初描述了外胚层命运图和执行这些命运所需的信号通路。在这里，我们将讨论该领域的现状，并反思近年来我们的理解发生了怎样的变化。