Origin and evolution of echinoderm pentamery, a combined paleontological and molecular biological approach

棘皮动物五体的起源和进化，古生物学和分子生物学相结合的方法

基本信息

批准号：
05404001
负责人：
OJI Tatsuo
金额：
$ 9.98万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05404001/
关键词：
Echinoderms Evolution Molecular biology Development 5放射相称

项目摘要

Echinoderms constitute one of the invertebrate animal phyla that originated in the Cambrian and survived to the Recent seas. The phylum is characterized by the pentamerous symmetry in the adult body plan. The purpose of this project has been to clarify when and how this character evolved, as well as its functional significance, from the viewpoints of paleontology, embryology and molecular biology.1. Fossil records ; Because the late pre-Cambrian Tribrachidium has trimerous symmetry, some researchers consider that trimery presedes pentamery in echinoderms. However, it is dubious that Tribrachidium is an echinoderm. It is known that Cambrian echinoderms already had pentamerous symmetry. The pentamerous pattern of Cambrian echinoderms is in fact the '2-1-2 pattern', in which two of the three branches branches into two to make five branches. This pattern is wide spread in later echinoderms, therefore, it is reasonable to consider that the true pentamerous pattern evolved from the 2-1-2 pattern.2. Embryology ; In the development of echinoderms, pentamerous symmetry first appear when the water vascular system is formed and where the water vascular system is segmented into five projections. Detailed observation of the development of water vascular systems is therefore important to understand the mechanisms of the formation of pentamerous symmetry.3. Molecular biology ; It is not yet known what kind of genes control the formation of pentamerous body plan. From the known significance of homeogenes in body plan formation, it is not too much a speculation to consider that homeogenes are involved in the making of pentamery in echinoderms. In this study, DNA primers have been designed to PCR amplify a region of homeobox of some echinoids. As a result, some target DNA fragments have successfully amplified. The relationship between the expression of homeogenes and the formation of pentamery is now being investigated.

棘皮动物构成起源于寒武纪的无脊椎动物动物门之一，并在最近的海洋中生存。门的特征是成人身体计划中的五型对称性。从古生物学，胚胎学和分子生物学的角度来看，该项目的目的是阐明该特征何时以及如何发展其功能意义。1。化石记录；由于晚期的前三曲菌植物具有扭曲的对称性，因此一些研究人员认为，构图在棘皮动物中预示了五聚会。然而，可疑的是，tribrachidium是棘皮动物。众所周知，寒武纪的棘皮动物已经具有五型对称性。寒武纪棘皮动物的五型五型模式实际上是“ 2-1-2模式”，其中三个分支中的两个分支分为两个分支，以建立五个分支。因此，这种模式在后来的棘皮动物中广泛传播，因此，可以考虑到2-1-2模式演变的真实五聚体模式是合理的。2。胚胎学；在棘皮动物的开发中，当形成水血管系统并将水血管系统细分为五个投影时，五型对称性首先出现。因此，对水血管系统发展的详细观察对于了解五型对称性形成的机制很重要3。分子生物学；尚不知道哪种基因控制五角星身体计划的形成。从遗传基因基因形成的已知意义来看，考虑到孢子中的孢子虫与棘皮动物的制造有关，这并不是一个猜测。在这项研究中，DNA引物旨在PCR扩大某些棘突类似的同源型区域。结果，一些目标DNA片段已成功扩增。现在正在研究同源基因的表达与五聚体的形成之间的关系。