Abstract—Differentiation of body axes during formation of primary body plan is one of the most fundamental processes in metazoan development. How did body axes emerge in the course of animal evolution? How did developmental processes associated with axes differentiation evolve? The basal metazoans, representatives of the phylum Cnidaria, are valuable objects for resolving these questions, since they have an evolutionarily simple body plan and only one (oral-aboral) body axis. The high abundance and diversity of the modes of asexual reproduction is an interesting feature of this group. In this review, we summarized the data on the establishment of primary body axis and differentiation of main morphological structures during asexual reproduction in representatives of the class Scyphozoa. We found that the relative orientation of the parental and offspring body axes varies significantly and depends on the mode of asexual reproduction, and that the same body parts of the offspring polyp or medusa can be formed from different parts of the parental organism. The high plasticity of scyphozoan developmental processes can be explained by assuming that various types of asexual reproduction evolved from regeneration processes in this group. To test this assumption, it is necessary to study the molecular mechanisms of differentiation of the primary body axis and the body parts during regeneration and asexual reproduction of scyphozoans.

中文翻译：

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壶铃虫生命周期过渡过程中口-鼻轴和身体部位的分化

摘要-在形成初级身体计划期间体轴的分化是后生动物发展中最基本的过程之一。体轴是如何在动物进化过程中出现的？与轴分化相关的发育过程如何演变？矢车菊的基部后生动物是解决这些问题的有价值的对象，因为它们具有进化上简单的身体计划，并且只有一个（口腔-口腔）身体轴。无性生殖方式的高丰度和多样性是该群体的一个有趣特征。在这篇综述中，我们总结了有关Scyphozoa类无性繁殖过程中主要器官轴的建立和主要形态结构分化的数据。我们发现，亲代和后代体轴的相对方向差异很大，并且取决于无性繁殖方式，并且后代息肉或美杜莎的相同身体部位可以由亲代生物的不同部位形成。可以通过假设本组中的再生过程进化出各种类型的无性生殖来解释后生动物的高可塑性。为了验证这一假设，有必要研究鞘氨醇的再生和无性繁殖过程中主要身体轴和身体部位分化的分子机制。可以通过假设本组中的再生过程进化出各种类型的无性生殖来解释后生动物的高可塑性。为了验证这一假设，有必要研究鞘氨醇的再生和无性繁殖过程中主要身体轴和身体部位分化的分子机制。可以通过假设本组中的再生过程进化出各种类型的无性生殖来解释后生动物的高可塑性。为了验证这一假设，有必要研究鞘氨醇的再生和无性繁殖过程中主要身体轴和身体部位分化的分子机制。