Evolution in frontier environments

前沿环境的演变

基本信息

批准号：
15340174
负责人：
CHIBA Satoshi
金额：
$ 10.56万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Ecological and genetic process of adaptive radiation were examined using endemic land snail genus Mandarina of the oceanic Ogasawara Islands in the northwestern Pacific. Based on the habitat analysis, morphological analysis, and examination of the mitochondrial DNA sequence variations, we showed that hybridization between sympatric species occurred by alteration of habitat use due to environmental change. This suggests that speciation and adaptive radiation are still in progress in Mandarina. In addition, populations with unique shell morphologies were found in a hybrid zone constituted between morphologically closely related species. This suggests that hybridization is an important source of creating novel morphology and evolutionary novelty.Phylogenetic relationship among the species of the land snails Euhadra in the mainland of Japan was estimated on the basis of mitochondrial DNA sequences. Repeated expansion and immigration have occurred in Euhadra, associated with climatic change during the Pleistocene. Complex spatial structure in genetic variations was created by mixing and isolation that were accompanied with the climatic change.Relationship between intertidal gastropoda Batillaria cumingii and its parasites was examined on the basis of ecological, morphological and genetic (mitochondrial DNA and nuclear ITS gene) analysis. Genetic analysis revealed that these parasites include a large number of cryptic species. These species showed less geographical variations in genetic variations. On the other hands, Batillaria showed a high level of geographical variations in genetic components. Ecological speciation due to habitat shift would be a main cause of diversification of parasites in intertidal gastropoda.

使用西北太平洋的海洋ogasawara群岛的地方性蜗牛属的生态和遗传过程检查了自适应辐射的生态和遗传过程。根据栖息地分析，形态分析和线粒体DNA序列变化的检查，我们表明同胞物种之间的杂交是由于环境变化而改变栖息地使用而发生的。这表明普通话中的物种形成和适应性辐射仍在进行中。此外，在形态密切相关的物种之间构成的混合区中发现了具有独特壳形态的种群。这表明杂交是建立新的形态和进化新颖性的重要来源。根据线粒体DNA序列，估算了日本大陆的土地蜗牛snails Euhadra物种之间的晶体发育关系。 Euhadra发生了反复的扩张和移民，与更新世期间的气候变化有关。遗传变异中的复杂空间结构是通过伴随气候变化的混合和隔离来创建的。潮间胃胃肠道batillaria cumingii之间的关系与其寄生虫之间的关系基于生态，形态学，形态学和遗传（线粒体DNA和核核的基因分析）。遗传分析表明，这些寄生虫包括大量隐性物种。这些物种在遗传变异方面显示出较少的地理变异。另一方面，Batillaria在遗传成分中显示出很高的地理变化。由于栖息地转移而引起的生态形成是导致潮间胃足多种寄生虫多样化的主要原因。