中国科学院昆明动物研究所机构知识库

在进化过程中，产生了多种多样的动物，但就某一类群来说，它们之间的进化相对比较保守，尤其躯体结构（body plan）被认为是在动物进化中最保守的特征之一。然而，与其它所有两侧对称动物不一样的是，棘皮动物（Echinoderm）在胚胎发育的早期展现出两侧对称，而在成体却转变成了辐射对称的躯体结构，这一例外无疑对我们所直观看出的门级别所共享的躯体结构特征提出了质疑。棘皮动物幼体的两侧对称和成体的辐射对称具有如此大的差异，一定有一些中间状态的个体或发育时期存在，阐明棘皮动物躯体结构的对称性变化是进化发育生物学中的一个重要的问题。但是，目前对躯体结构的研究通常都是单基因水平的研究，这使得我们到目前为止仍然对这一过程知之甚少。因此，本研究中，我们首先解析得到了589 Mb的海百合（Oxycomanthus japonicus）和973 Mb的绿海胆（Lytechinus variegatus）基因组，其中海百合的contig和scaffold N50分别达到了 18 Kb和623 Kb；绿海胆分别为12 Kb和628 Kb。接着，我们采用了大量的比较基因组学方面的分析，来系统性的比较棘皮动物和脊索动物之间的共性和特性。最终，我们识别出了一些和细胞骨架调控相关的基因受到了正选择和发生了扩张。而且，通过动态基因网络的分析我们筛选得到了一些可能导致棘皮动物躯体结构变化的基因。这将对我们系统性的解析棘皮动物躯体结构的进化历史和意义奠定基础，为我们更好的理解棘皮动物的适应性进化甚至整个门级别的躯体结构的共性的路径带来重新的思考。 

In the process of evolution, there are a variety of animals have been produced. However, if we grouped them according to the taxonomic perspective, each of them has its relatively conservative side, especially for the body plan as one of the most conservative feature. However, Echinoderm, is different from all of the bilateral animals, they have a bilateral symmetry body plan in their larval stage, and change to radial symmetry in adult stage. This exception undoubtedly raises questions about the shared body plan designs we considered just by our eyes. The great distinguish of echinoderm between larval and adult body plan, there must be some intermediate state individual or development period, and thus the change of body plan symmetry is a very important issue in evolutionary and developmental biology. However, current study on body plan mainly in the single gene level, and make us know little about this process so far.In this study, we assembled and got the 589 Mb of feather star (Oxycomanthus japonicus) and 973 Mb of sea urchin (Lytechinus variegatus) sequences, and the contig and scaffold N50 of feather star are 18 Kb and 623 Kb, respectively; and sea urchin are 12 Kb and 628 Kb respectively. Then we systematically compared the common and unique characteristics between echinoderms and chordates by comparative genomics strategies. Finally, we identified some genes which are related to the regulation of cytoskeleton are positively selected and expanded. Moreover, we got some leading genes which may influence the change of echinoderm body plan through dynamic network biomarkers analysis. All of these results will lay the foundation for us to understand the evolution history or significance, and bring about the rethinking of the adaptive evolution of echinoderm or even the method which we used to find the path of the commonness of body plan among the phylums.