The germline is unique and immortal (or at least its genome is). It is able to perform unique jobs (meiosis) and is selected for genetic changes. Part of being this special also means that entry into the germline club is restricted and cells of the soma are always left out. However, the recent evidence from multiple animals now suggests that somatic cells may join the club and become germline cells in an animal when the original germline is removed. This “violation” may have garnered acceptance by the observation that iPScells, originating experimentally from somatic cells of an adult, can form reproductively successful eggs and sperm, all in vitro. Each of the genes and their functions used to induce pluripotentiality are found normally in the cell and the in vitro conditions to direct germline commitment replicate conditions in vivo. Here, we discuss evidence from three different animals: an ascidian, a segmented worm, and a sea urchin; and that the cells of a somatic cell lineage can convert into the germline in vivo. We discuss the consequences of such transitions and provide thoughts as how this process may have equal precision to the original germline formation of an embryo.

中文翻译：

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体细胞转化为生殖细胞谱系：违规还是启示？

种系是独特且不朽的（或者至少它的基因组是）。它能够执行独特的工作（减数分裂）并被选择用于遗传变化。这种特殊的一部分也意味着进入种系俱乐部受到限制，躯体细胞总是被排除在外。然而，最近来自多种动物的证据表明，当原始种系被移除时，体细胞可能加入俱乐部并成为动物的种系细胞。这种“违规”可能已经通过观察获得认可，即实验性起源于成人体细胞的 iPS 细胞可以在体外形成成功繁殖的卵子和精子。用于诱导多能性的每个基因及其功能通常在细胞和体外条件下发现，以指导种系定型在体内复制条件。在这里，我们讨论来自三种不同动物的证据：海鞘、节肢蠕虫和海胆；并且体细胞谱系的细胞可以在体内转化为种系。