Mitochondrial DNA Sequence Variation and Population Structure of Cetaceans around Taiwan
| Autor: | Lin, Yi-Jung, 林怡蓉 |
|---|---|
| Rok vydání: | 1997 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 85 Mitochondrial DNA Sequence Variation and Population Structure of Cetaceans around Taiwan Abstract: Cetaceans have been abundant and distributed widely around Taiwan in the past. However, there were only few research on cetacean and only in taxonomy and population estimation at the southwest coastal area so far. The purpose of my thesis is to investigate (1) the phylogeny relationship among different species, and (2) population structure of few common species around Taiwan to check the correlation with geographical and morphological variation. Dr. L.-S. Chou''s research team has collected cetacean carcasses from stranding or fishery activity since 1993. In total, there were 16 species. I selected one to three muscle samples from each species for the first part of my thesis and about 10 muscle samples of three common species here, Stenella attenuata, Stenella longirostris, and Tursiops truncatus, from both east and west coasts of Taiwan for my second part of thesis. All these muscle samples were executed mt DNA sequence analysis on the control region. In addition, the morphometric measurement of the later three species was also collected for cladistic analysis. The mt DNA control region sequence of 16 local species and 5 foreign species from published gene bank were compared and structured into phylogeny tree by Neighbor-joining method. I suggest that Physeteriodea is more similar as those in the Mysticeti than other members in Odontoceti, and Ziphioidea is separated from Delphinoidea in Odontoceti. Further more, Ocinus orca showed obvious distance from the Globicephalinae, which has been stated as a distinguished group from the other species in Delphinidae. Except the taxon Globicephalids, The genetic relationship among other members of Dephinids not show any steady and distinguishable pattern.According to Neighbor-joining method and the maximum parsimony analysis of mt DNA sequence, the phenomenon of stock separation of Stenella attenuata and S. longirostris was not obvious, but slightly obvious among Tursiops truncatus. The nucleon diversity index of S. longirostris is higher than other two species. Thus, it is suggested that the population size of S. longirostris around Taiwan is either quite large or distributed continuously with great variation. One special specimen of a adult S. longirostris with the smaller body length is speculated as a mid form collected from the continuously distributed populations from Japan to Thailand. Three special Tursiops truncatus with greater genetic distance from other individuals of the same species is speculated as immigrants near Peng-hu Island during winter migration. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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