政院國家科學委員會專題研究計畫 期中進報告政院國家科學委員會專題研究計畫 期中進報告用核內基因之序研究青剛櫟與杉之親緣地形式 (2/3) 期中進報告(簡版) 用核內基因之序研究青剛櫟與杉之親緣地形式 (2/3) 期中進報告(簡版) 計 畫 別 ： 個別型 計 畫 編 號 ： NSC 95-2621-B-002-002- 執 期 間 ： 95 08 月 01 日至 96 07 月 31 日 執 單 位 ： 國臺灣大學植物科學研究所 計 畫 主 持 人 ： 讚標 處 方 式 ： 期中報告提供公開查詢 中 華 民 國 96 06 月 21 日 PARTIAL CONCORDANCE BETWEEN NUCLEAR AND ORGANELLE DNA IN REVEALING THE GENETIC DIVERGENCE AMONG QUERCUS GLAUCA (FAGACEAE) POPULATIONS IN TAIWANF. L. Shih,1,* Y. P. Cheng,1,* S. Y. Hwang,yand T. P. Lin2,*Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan, Republic of China; andyGraduate Institute of Biotechnology, Chinese Culture University, Yangmingshan, Taipei 111, Taiwan, Republic of ChinaQuercus glauca (Thunb. ex Murray) Oerst (Fagaceae) has a wide distributional range in Taiwan. In this study, the evolutionary history and the most genetically divergent sites of Q. glauca were studied using a nuclear gene marker, glyceraldehyde-3-phosphate dehydrogenase. Also, the consistency of the results obtained from nuclear gene and cytoplasmic loci was investigated. Using a genealogical approach (TCS software), we determined haplotypes and their relationships to one another. We used the level of divergence for each population from the remaining populations (calculated as mean values of pairwise population differentiation, FST, for each population) to locate the most genetically divergent areas in Taiwan. According to the average FST of each population in comparison with the remaining ones, a peak was found in the northern part of centralTaiwan, and another was found in the southeastern region. The peak profiles of the mean FSTvalues for all three DNA data sets (nDNA, cpDNA, and mtDNA) showed similar trends on both sides of the Central Mountain Ridge, except for the mtDNA sequence on the western side. This study suggests that two potential refugia existed in Taiwan during the last glaciation: one in the northern part of central Taiwan and another in southern Taiwan.Keywords: glyceraldehyde-3-phosphate dehydrogenase, phylogeography, refugium, genetic divergence, Taiwan, Quercus glauca.IntroductionUsing molecular markers in combination with paleoecolog- ical studies for the analysis of the late Quaternary history of angiosperms in order to deduce historical information from their present-day geographical distributions has led to the recognition of glacial refugia of many species of Europe, North America, and Asia (Comes and Kadereit 1998). DNA sequences can even provide evidence of refugium sites that have not been detected by geological or fossil data (Rowe et al. 2004). The power of nucleotide sequences comes from the fact that they can be organized into hierarchically or- dered networks of descent and can provide historical infor- mation that nonordered markers are unable to provide (Schaal et al. 1998). The availability of DNA sequence data and the development of coalescent-based analysis of allele ge- nealogies can therefore form the basis of the study of intra-specific processes within a phylogenetic framework (Avise 2000) and can be used to examine the geographic distribu- tion of genetic variations, postglacial recolonizations, and the ways in which recent evolutionary history has shaped pat-terns of intraspecific variations of a wide range of species (Newton et al. 1999).Gene flow between populations may be achieved throughpollen or seeds. Pollen-mediated gene flow is not necessarilyfaster than gene flow by seeds; however, the rate of the flow through pollen in tree species like oaks with large heavy seeds is faster than that through seeds because pollen grains are smaller and can be carried more easily over longer distances by diverse agents including wind and insects (Ennos 1994). In addition, the chloroplast genome is haploid, whereas nuclear genomes are diploid or polyploid; thus, the effective popula- tion size of cytoplasmic genomes is half that of the diploid nu- clear genome (McCauley 1995; Moore 1995). The deeper coalescence times expected for nuclear haplotypes will obscure spatial genetic patterns revealed by the plastid genomes. To test this idea, we compared the spatial genetic pattern of the plastid genome, including mitochondrial DNA (mtDNA) and chloroplast DNA (cpDNA), with nuclear DNA (nDNA) of a subtropical tree species, Quercus glauca (Fagaceae). In addi- tion, we examined whether the patterns from different genemarkers reflect different genetic histories, which may be inte- grated to postulate the possible historical events that have oc- curred in Q. glauca in Taiwan. Quercus glauca is a member of the subgenus Cyclobala- nopsis. Cyclobalanopsis is monophyletic within the genus Quercus according to molecular data (Manos et al. 2001). The subgenus Cyclobalanopsis contains ca. 122 species in tropical and subtropical eastern Asia (Luo and Zhou 2001). In consequence, Cyclobalanopsis is considered to be of tropi- cal and subtropical origin (Luo and Zhou 2001). Amon