Studies of taxonomy, phylogeny and peculiar evolution of marine organisms inhabiting marine lakes from the viewpoint of vacarism

从vacarism的角度研究栖息在海洋湖泊的海洋生物的分类、系统发育和奇特进化

基本信息

批准号：
13304065
负责人：
HARA Yoshiaki
金额：
$ 25.71万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

In Palau Archipelago, about 80 marine lakes are located around Rocky Island District. These lakes are isolated from open sea and provide closed marine ecosystem to oceanic life systems. Almost all are geologically and genetically isolated from those inhabiting open seas, at least ten thousand years ago when the marine lakes were formed after he last glacial age. They show unique gross morphology, therefore it can be supposed that they have drifted on their own evolutionary processes. During our seven expeditions to Palau, 19 marine lakes have been accessed. On the limnological sense, these are divided into two of the holomictic and meromictic lakes. In the case of seaweeds in marine lakes, the similar species compositons and common dominant species share depending on these types of marine lakes. This is the center of this project for taking the evidences of their peculiar evolution of dominant or represenntative seaweeds and other groups of animal assembrages in the marine lakes based … More on the analyses of morphology and molecular phylogeny. The estimation of marine lakes' ages has been tried using the radio isotope and micropaleontological methods on the basis of sediments deposited in the bottom of lakes. Unfortunately, the suitable samples for these analyses could not be collected from all marine lakes we accessed. Consequently, we have to consider that the standard age of marine lakes in Palau is approxmately ten thoughsand years previously thought.From the results obtained here, the identification system of seaweeds in marine lakes based on their external morphology and internal strucutres was established with the verification of the molecular phylogenetic analysis. Owing to use this system, we could compare the genetic divergences of seaweeds inside and outside, as well as inter and intra marine lakes. At present, we could not show the clear evidences to occur the peculiar evolution of marine life systems in marine lakes, however, the possibilities could be exhibit on animal assebrages using mitochondrial genomes. While the peculiar evolution of seaweeds was mostly neglected at 18SrDNA, rbcL and ITS region levels. Further investigations will be needed after introducing molecules with much more rapid evolutionary speed or another methods possessing the resolving power to much more closely phylogenetic relationships. Less

在帕劳群岛，大约有 80 个海洋湖泊位于洛基岛区周围，这些湖泊与公海隔绝，为海洋生物系统提供了封闭的海洋生态系统，几乎所有湖泊都与居住在公海的生物隔离了至少一万年。当海洋湖泊在最后一个冰河时代形成时，它们表现出独特的总体形态，因此可以假设它们在我们对帕劳的七次探险中，有19个海洋湖泊。从湖泊学的角度来看，这些湖泊分为全合湖和半合湖两种，根据这些类型的海洋湖泊，它们具有相似的物种组成和共同的优势物种。该项目的中心是根据分析，获取海洋湖泊中主要或代表性海藻和其他动物组合的特殊进化证据。已经尝试根据沉积在湖底的沉积物使用放射性同位素和微古生物学方法来估计海洋湖泊的年龄，不幸的是，无法从所有海洋中收集到适合这些分析的样本。根据我们检查过的湖泊，我们必须考虑到帕劳海洋湖泊的标准年龄约为之前认为的十年。根据此处获得的结果，海洋中海藻的识别系统通过分子系统发育分析验证了湖泊的外部形态和内部结构，目前，我们可以比较海洋湖泊内部和外部以及内部和内部的海藻遗传差异。我们无法提供明确的证据来证明海洋湖泊中海洋生物系统的特殊进化，但是，利用线粒体基因组在动物组合中可以展示出这种可能性，而海藻的特殊进化主要是这样的。在引入具有更快进化速度的分子或具有更密切的系统发育关系解析能力的其他方法后，需要在 18SrDNA、rbcL 和 ITS 区域水平上进行进一步的研究。