PDF(Pubmed)
Abstract：
Germ cells (reproductive cells and their progenitors) give rise to the next generation in sexually reproducing organisms. The loss or removal of germ cells often leads to sterility in established research organisms such as the fruit fly, nematodes, frog, and mouse. The failure to regenerate germ cells in these organisms reinforced the dogma of germline-soma barrier in which germ cells are set-aside during embryogenesis and cannot be replaced by somatic cells. However, in stark contrast, many animals including segmented worms (annelids), hydrozoans, planaria, sea stars, sea urchins, and tunicates can regenerate germ cells. Here I review germ cell and gonad regeneration in annelids, a rich history of research that dates back to the early 20th century in this highly regenerative group. Examples include annelids from across the annelid phylogeny, across developmental stages, and reproductive strategies. Adult annelids regenerate germ cells as a part of regeneration, grafting, and asexual reproduction. Annelids can also recover germ cells after ablation of germ cell progenitors in the embryos. I present a framework to investigate cellular sources of germ cell regeneration in annelids, and discuss the literature that supports different possibilities within this framework, where germ-soma separation may or may not be preserved. With contemporary genetic-lineage tracing and bioinformatics tools, and several genetically enabled annelid models, we are at the brink of answering the big questions that puzzled many for over more than a century.
摘要：
生殖细胞（生殖细胞及其祖细胞）在有性繁殖的生物体中产生下一代。生殖细胞的损失或去除通常会导致已建立的研究生物如果蝇的不育，线虫,青蛙,和老鼠。这些生物体中生殖细胞的再生失败增强了种系-体细胞屏障的教条，其中生殖细胞在胚胎发生过程中被搁置，并且不能被体细胞取代。然而,形成鲜明对比的是,许多动物，包括分段蠕虫（环节动物），水生动物,planaria,海星，海胆,被膜可以再生生殖细胞。在这里，我回顾了生殖细胞和性腺的再生，丰富的研究历史可以追溯到20世纪初，在这个高度再生的群体中。例子包括来自整个环节动物系统发育的环节动物，跨越发展阶段，和生殖策略。成年环节动物再生生殖细胞作为再生的一部分，嫁接,和无性繁殖。在消融胚胎中的生殖细胞祖细胞后，环节动物也可以恢复生殖细胞。我提出了一个框架来研究环节动物生殖细胞再生的细胞来源，并讨论在这个框架内支持不同可能性的文献，细菌-体细胞分离可能会或可能不会被保存。借助当代遗传谱系追踪和生物信息学工具，和几个基因使能的Annelid模型，我们正处于回答困扰许多人一个多世纪的重大问题的边缘。
