陳章波臺灣大學：漁業科學研究所楊明哲Yang, Ming-CheMing-CheYang2007-11-282018-07-062007-11-282018-07-062004http://ntur.lib.ntu.edu.tw//handle/246246/59372西太平洋長期以來被公認為生物歧異度中心，探索各物種地理親緣關係，可瞭解此地區生物多樣性形成機制。本研究以分子遺傳標誌，粒線體 AT-rich片段，探討現今印度西太平洋地區活化石三棘鱟之遺傳變異。總樣本數為82隻個體採集自台灣、泰國暹羅灣(GT)及安達曼海(AB)三個地區，共五個族群；其中台灣地區包含金門(TK)、澎湖東衛(TD)及澎湖鐵線尾(TT)三個族群。 本研究以鄰接演算法建構三棘鱟族群之單型親緣關係及以最短距離網狀圖，並由化石紀錄及分子鐘評估分歧時間，支持漸新世晚期到中新世早期（21-27百萬年前）印度洋及西太平洋間族群的顯著分歧，並支持印度西太平洋板塊間之隔離作用。另推論中新世晚期到中期（17-21百萬年前）南中國海盆的持續擴張在阻礙三棘鱟基因交流上扮演關鍵角色。由族群成長係數及單峰之mismatch distribution分析支持暹羅灣族群急遽擴張現象，並推論其為受到冰期造成的海面及棲地波動的影響。另外發現鐵線尾三棘鱟族群曾發生嚴重的瓶頸效應，推論源於近年來族群數量衰減及於封閉海灣長久近親繁殖造成的結果。最後藉由三棘鱟地理親緣關係以及族群遺傳數據提出對印度西太平洋三棘鱟在保育上之建議。The Indo-West-Pacific region (IWP) hosts the highest marine biodiversity on earth. The concordance among different species can be used to deduct the common mechanism that forms the IWP marine biodiversity. Genetic variation of mitochondrial AT- rich region in the “living-fossil” horseshoe crab, Tachypleus tridentatus, were revealed for 82 individuals collected from 5 populations in 3 regions, including southern Burma coast of Andaman Sea (AB), Angsila in Gulf of Thailand (GT), and Kinmen (TK), Donwei (TD), Tehsiwei (TT) in Taiwan. Haplotype phylogeny constructed by neighbour-joining algorithm, the network derived from the minimum spanning network, and dating by fossil records demonstrated that a significantly deep divergence between the populations in Indian and Pacific Ocean, suggesting a pattern of Indian-Pacific tectonic plate divergence from late Oligocene to early Miocene (21-27 Ma). In addition, it also indicated that Taiwan population formed a significantly different clade from Gulf of Thailand divergence time indicates that South China Sea Basin might play an important role in retarding gene flow of between the T. tridentatus populations of southern and northern South China Sea from early Miocene to middle Miocene (17-21 Ma). The demography parameter and unimodal mismatch distribution indicates the sudden range expansion of T. tridentatus population in Gulf of Thailand and affected by sea level and habitat fluctuation during glaciations. The mismatch distribution indicated the bottleneck effect on Donwei population due to recent population size decline and inbreeding in this close bay. The implications of phylogeography and demography towards the T. tridentatus conservation in the IWP are also highlighted.Chapter 1 Introduction 1 1.1 Evolutionary history of Horseshoe crab 1 1.2 Life history and phylogeography of horseshoe crab 3 1.3 Marine biogeography in the Indo-West Pacific 5 1.4 Glacial effect on population demography of Tachypleus tridentatus 6 1.5 The question about phylogeography of horseshoe crab in the IWP 7 Chapter 2 Materials and Methods 9 2.1 Collection of Samples 9 2.2 DNA extraction, Polymerase chain reaction (PCR), and Sequencing 9 2.3 Phylogeny construction 10 2.4 Network analysis 11 2.5 Population genetics analyses 12 2.6 Demography 12 Chapter 3 Results 14 3.1 Phylogeny and Network Reconstruction 14 3.2 Population Structure 15 3.3 Demography 16 Chapter 4 Discussions 18 4.1 Ancient divergence of Tachypleus tridentatus? 18 4.2 Unexpected divergence in the South China Sea 19 4.3 Glacial effects on population demography 21 4.4 Implications for conservation 24 Chapter 5 Conclusion 26 Reference 28 Table 32 Figure 40 Appendix 45629417 bytesapplication/pdfen-US印度西太平洋地理親緣鱟分子遺傳演化活化石Tachypleus tridentatusphylogeographyIndo-West Pacificevolutionhorseshoe crabliving fossilmolecular genetics[SDGs]SDG15otherhttp://ntur.lib.ntu.edu.tw/bitstream/246246/59372/1/ntu-93-R91243020-1.pdf