|
|
Hokkaido University Collection of Scholarly and Academic Papers >
Theses >
博士 （理学） >
Taxonomic and molecular phylogenetic studies of the genus Colpomenia (Scytosiphonaceae, Phaeophyceae)
|
Files in This Item:
|
|
|
Related Items in HUSCAP:
|
| Title: | Taxonomic and molecular phylogenetic studies of the genus Colpomenia (Scytosiphonaceae, Phaeophyceae) |
| Other Titles: | 褐藻フクロノリ属（カヤモノリ科）の分類学的および分子系統学的研究 |
| Authors: | DY, Michael Jacob Cleto Browse this author |
| Issue Date: | 25-Mar-2024 |
| Publisher: | Hokkaido University |
| Abstract: | The classification of the brown algal family Scytociphonaceae still remains problematic because of their morphological plasticity and also the molecular phylogenetic inconsistencies among its genera. With the help of several phycologists, some of the issues have been addressed, but the problem is still there especially in the genus Colpomenia. I attempted in this study to resolve taxonomic problems within this genus and its species by combining multi-gene molecular data with morphological observations and life histories. I assessed the taxonomy of all known globular species, using Colpomenia samples from Japan, Russia, Australia, and Portugal. Three molecular markers were used for phylogenetic analyses: mitochondrial cox3 gene and plastidal rbcL and psaA genes. In all cox3, rbcL, and psaA trees reconstructed, this genus revealed four major evolutionary lineages (Lineages I– IV). In addition, a new species has been discovered while conducting this research. Colpomenia borea is characterized by its small globular to ovoidal thalli and thin thallus membrane and is epiphytic on the brown alga Stephanocystis. This species was found in the Pacific coast of Hokkaido, Japan, and Magadan, Far East Russia which are the coldest regions in the distributional range of Colpomenia. This study revealed independence of each of Lineages I–IV, suggesting polyphyly of the genus Colpomenia. Lineage I consisted of Colpomenia sinuosa which is the generitype of the genus. Lineage II consisted of C. claytoniae, C. expansa, C. peregrina, and C. borea, which have globose thalli. Since this Lineage was distantly related to the generitype C. sinuosa, a new genus name should be proposed for the Lineage II. Lineages III and IV were composed of C. ecuticulata and C. ramosa, respectively. These Lineages were also distantly related to C. sinuosa in cox3 analyses. In cox3 trees, highly supported subclades were formed in C. sinuosa and C. claytoniae, suggesting multiple species within those species. Colpomenia peregrina also showed large intraspecific sequence differences. Four DNA-based species delimitation analyses (ABGD, ASAP, PTP, bPTP) were also conducted for Colpomenia species, using cox3 sequences. Results of ABGD and ASAP were similar, suggesting two or four species within C. sinuosa and a single species for C. claytoniae and C. peregrina. In contrast, PTP and bPTP yielded nine species within C. sinuosa and five species within C. claytoniae while a single species for C. peregrina. Species boundaries that corresponded among all species delimitation analyses supported the current classification except for C. sinuosa which was divided into two by the boundary. Colpomenia sinuosa could include at least two species. Because globose Colpomenia are similar in gross morphology, they may have been misidentified. In this study, molecular identification of Colpomenia species from Japan was conducted, and their more accurate distributional ranges were revealed in Japan. |
| Conffering University: | 北海道大学 |
| Degree Report Number: | 甲第15748号 |
| Degree Level: | 博士 |
| Degree Discipline: | 理学 |
| Examination Committee Members: | (主査) 教授 小亀 一弘, 教授 柁原 宏, 准教授 阿部 剛史 |
| Degree Affiliation: | 理学院（自然史科学専攻） |
| Type: | theses (doctoral) |
| URI: | http://hdl.handle.net/2115/92278 |
| Appears in Collections: | 課程博士 (Doctorate by way of Advanced Course) > 理学院(Graduate School of Science)
学位論文 (Theses) > 博士 （理学）
|
|
