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题名	东亚—北美间断代表类群的分子生物地理与进化研究
作者	聂泽龙
学位类别	博士
答辩日期	2008-01-23
授予单位	中国科学院昆明植物研究所
授予地点	昆明植物研究所
导师	孙航
关键词	东亚 北美东部 北美西部 间断 生物地理 透骨草 钩毛草属 檫木属 爬山虎属 漆属 Orontioideae亚科 木兰科
其他题名	Molecular Biogeography and evolution on representative plants disjunct between eastern Asia and North America
学位专业	植物学
中文摘要	在全球生物地理学研究中，北半球温带成分的间断是最著名和复杂的地理分布模式，一直都是研究和关注的热点。本论文从种到科共选取了7组不同级别的代表性类群: 透骨草科透骨草Phryma leptostachys、茜草科钩毛草属Kelloggia、樟科檫木属Sassafras、葡萄科爬山虎属Parthenocissus、漆树科漆属Toxicodendron、天南星科Orontioideae亚科、以及木兰科Magnoliaceae。通过对每个类群进行系统发育重建以及分子生物地理分析等，探讨它们起源、分化和散布途径。通过对间断类群的迭合分析，探索形成东亚—北美间断分布的时空演化规律和机理以及对东亚植物区系的启示意义。 透骨草(Phryma leptostachys)：透骨草科透骨属，单种属，间断分布于东亚与北美东部的多年生草本。通过对ITS、rps16以及trnL-F序列的研究表明东亚和北美的类群明显地分成两支。它们分化的时间约为3.68--5.23百万年前。谱系地理和DIVA分析揭示透骨草起源于北美，然后经白令陆桥迁移到东亚。对23个形态特征的多元分析表明东亚和北美的居群在形态上并不存在明显的差别，而分子上存在明显的变异，这可能是由于其生态环境相似而造成的形态保守。 钩毛草属(Kelloggia)：茜草科，仅2种，间断分布于北美西部和我国西南山地。叶绿体rbcL、atpB-rbcL和rps16数据支持本属的单系地位。间断分化时间约为5.42±2.32百万年前。起源地分析以及DIVA分析表明钩毛草属起源于旧世界。本属的洲际间断分布模式可能是从亚洲通过长距离传播到北美。 檫木属(Sassafras)：来自樟科，包含3个种，间断分布于东亚(S. tzumu 和 S. randaiense)和北美东部(S. albidum)。ITS和rpl16, trnL-F, psbA-trnH的系统发育分析结果表明Sassafras为一个单系类群，北美东部的种S. albidum与东亚的两个种形成姐妹类群。它们形成洲际间断的时间为13.80至16.69百万年前。它可能是北半球的一个孑遗类群。我国大陆与台湾的两个种的分化时间约为0.61至2.23百万年前，台湾种最有可能来自于中国大陆。 爬山虎属(Parthenocissus)：是葡萄科中少有的以北温带分布为主的属之一，约15种，间断分布于东亚与北美东部。叶绿体(trnL-F, rps16, atpB_rbcL)和核基因(GAI1)研究表明本属为单系，并分成与其地理分布相吻合的东亚和北美两支。它们的分化时间经化石校正估算为14.37百万年前，这与第三纪古气候以及葡萄科化石证据相吻合，可能是通过白令海峡扩散形成的。 漆属(Toxicodendron)：是漆树科中少见的以北温带分布为主的类群，约有24种。核基因（ITS 和 NIA-i3）和叶绿体(trnL-F和ndhF) 序列，支持本属的单系地位，属内的裂果漆和毒漆藤组也是单系类群，但本属最大的漆树组则不为单系。两个主要的温带间断分布类群发现于毒漆藤组以及T. vernix – T. vernicifluum 之间，分化时间分别为14.55和9.24百万年前，DIVA与化石证据支持它们由东亚经北令海峡到北美的迁移路线。亚洲的裂果漆组与热带美洲的T. stratium 之间的泛热带性质间断分化时间大约在中新世早期的22.55百万年前。漆属的热带性质的间断更有可能是经北令海峡与北美再至中美的迁移路线，而不是常规的北大西洋的途径。 Orontioideae亚科: 属于天南星科，包括Symplocarpus, Lysichiton和Orontium三个属，是本科中少有的北温带属。Symplocarpus 间断分布于东亚和北美东部；Lysichiton 在东亚和北美西部各有一个种；单种属Orontium仅分布于北美东部。基于trnL-F和ndhF 的分子系统结果支持它们各自为单系类群。Symplocarpus 和Lysichiton的间断时间分别为4.49-6.88和4.02-7.18百万年前，它们可能在晚第三纪经白令陆桥由东亚传播到北美。尽管真天南星的种类远比原始类群丰富，但相对速率检测表明它们的trnL-F 序列的碱基替代率相近。第三纪气候变冷可能导致了天南星科原始类群的大量灭绝。 木兰科(Magnoliaceae)：3个核基因(PHYA, LFY, GAI1)的系统发育研究结果表明木兰科分为十二个主要的类群，这些类群大致与最近的分类修订中的组或亚组相对应。然而在木兰亚科内的大支间的系统关系仍不清楚，可能是由于早期辐射进化造成的。贝叶斯法推算的分化时间表明木兰亚科早期有着复杂的进化历史，它的分化始于始新世早期(54.57百万年前)，这与古气候和化石证据一致。木兰科在北半球的洲际间断至少发生于两个地质历史时期：一是发生于较近的中新世中期以后，包括两个明显的东亚与北美东部的温带间断谱系；另一个发生于渐新世以前，包含热带和温带孑遗间断类群。 本研究所选7组类群囊括了科，亚科，属和种不同的等级，包括了草本、木本、藤本等生活型；代表了北半球温带和泛热带间断模式以及北温带东亚—北美不同间断子类型。综合古地质学以及化石证据的系统发育与分子生物地理进化研究结果表明它们的间断分布格局是第三纪广布于北半球的北方热带森林成分(Boretropical flora)孑遗的假说。这种格局主要是在整个第三纪多次分化形成的。草本植物的间断分化时间大多在晚第三纪的中新世中期以后，而木本间断类群的分化大多在中新世前，另外北温带间断比泛热带间断也要年轻很多。白令陆桥对温带间断和泛热带间断类群的形成和演化都有重要作用。迁移扩散与隔离分化一样在北半球的间断分化中都起到了重要作用。本研究也揭示东亚植物区系是多次形成的，是新老兼备来源复杂的植物区系，具体表现在中国—日本成分的古老性和中国—喜马拉雅成分的年轻性。北半球第三纪曾发生大量的物种灭绝。东亚—北美地理间断格局的复杂也直接导致了中国-喜马拉雅成分来源的复杂性。形态保守和趋同在东亚北美间断中普遍存在，可能暗示北半球孑遗植物区系长期稳定和相似的生态环境。
英文摘要	Biogeographic disjunction in Northern Hemisphere is one of the most well-known and complicate patterns in the world. It has always been the hot spot for biogeographic researches and attentions. In this study, 7 representatives from species to family level were selected, i.e., Phryma leptostachys, Kelloggia, Sassafras, Parthenocissus, Toxicodendron, Orontioideae, and Magnoliaceae. Phylogenetic reconstruction, divergence time, and ancestral areas were analyzed for understanding their biogeographic origin, diversification, and migration. Moreover, sythensized analyses with these taxa may throw light on temporal and spatial evolutionary processes and mechansim of eastern Asia – North American disjunction and evolutionary implications on the eastern Asian flora. Phryma leptostachys: Phrymaceae, monotypic Phryma, and disjunct perennial herbs between eastern Asia and eastern North America. Molecular analysis of ITS, rps16, and trnL-F revealed two clades corresponding to their biogeographic distribution, with a divergence time of 3.68-5.23mya. Phylogeographic and DIVA results suggested their North American origin and migration to Asia via Bering strait. Multivariate analysis based on 23 quantitative morphological characters detected no geographic groups at the intercontinental level. The discordance of the molecular and morphological patterns may be explained by morphological stasis due to ecological similarity in both continents. Kelloggia: Rubiaceae, only 2 species, disjunct between western North America and northwestern China. Phylogenetic and biogeographic analysis of rbcL, atpB-rbcL, and rps16 supported the monophyly of the genus with a divergence time of 5.42±2.32mya. Ancestral area and DIVA analysis suggested an Old World origin and long distance dispersal to the New World. Sassafras: Lauraceae, 3 species, disjunct between eastern Asia (S. tzumu and S. randaiense) and eastern North America (S. albidum). Phylogenetic and biogeographic analysis of ITS, rpl16, trnL-F, and psbA-trnH suggested the monophyly of Sassafras with a divergence timeof 13.80-16.69 mya. Sassafras has a relict distribution in the northern hemisphere. The divergence time of the two eastern Asian species is estimated to be 0.61–2.23 mya with Sassafras randaiense from Taiwan most likely derived from an ancestor from continental China. Parthenocissus: one of the few north temperate genera of Vitaceae, 15 species, disjunct between eastern Asia and eastern North America. Phylogenetic analysis of trnL-F, rps16, atpB_rbcL, and GAI1 supported the monophyly of the genus and two clades corresponding to their distribution. A divergence time of 14.37 estimated for the genus is consist with paleoclimatological and fossil evidence with possible migration via Bering strait. Toxicodendron: ca. 24 species, one of the few north temperate taxa in Anacardiaceae. Phylogenetic analysis based on ITS, NIA-i3, trnL-F, and ndhF sequences suggested the monophyly of the genus, sect. Griffithii and Toxicodendron, but not sect. Venenata within the genus. Two temperate disjunctions were recognized from section Toxicodendron and T. vernix – T. vernicifluum with divergent times estimated to be 14.55 and 9.24 mya based on Bayesian method, respectively. DIVA results combined with fossil data suggested a migration route from eastern Asia to North America via Beringia. The subtropical – tropical disjunct between Asian section Griffithii and central American T. stratium was first detected with divergent time estimated around 22.55 mya. We proposed a similar Beringia route as the temperate disjuncts with subsequent movement to central America, rather than regular North Atlantic route. Orontioideae: few of the north temperate taxa in Araceae, including Symplocarpus, Lysichiton, and Orontium. Symplocarpus is disjunct in eastern Asia and eastern North America; Lysichiton has an intercontinental distribution in eastern Asia and northwestern North America; and the monotypic Orontium is restricted to eastern North America. Phylogenetic and biogeographic analyses of the trnL-F and ndhF supported the monophyly of Symplocarpus and Lysichiton with divergence at 4.49-6.88 and 4.02-7.18 mya, respectively. Eastern Asia was suggested to be the ancestral area of the Symplocarpus and Lysichiton with independent migrations via the Beringia in the late Tertiary. The relative rate test showed similar substitution rates of the trnL-F between the proto and the true aroids, although the latter has substantially higher species diversity. The proto Araceae perhaps suffered from a higher rate of extinction in the temperate zone associated with periods of climatic cooling in the Tertiary. Magnoliaceae: Three nuclear genes (PHYA, LFY, and GAI1) revealed that 12 major groups largely consistent with the recent taxonomic revision at the sectional and subsectional level. However, relationships at deeper nodes of the subfamily Magnolioideae remained poorly resolved, perhaps due to an early radiation of the subfamily. Bayesian dating suggested that a complicated divergent evolution of Magnolioideae began around the early Eocene (54.57mya), concordant with paleoclimatic and fossil evidence. Intercontinental disjunctions of Magnoliaceae in the Northern Hemisphere originated during at least two geologic periods. The more recent one occurred after the middle Miocene, producing two well-recognized temperate disjunct lineages between eastern Asia and eastern North America. The second may have occurred no later than the Oligocene, with ancient separations between or within tropical and relict temperate lineages. The 7 taxa used in this study were selected from family, subfamily, genus to species levels, including herbs, woods, and vines, and representing temperate and pantropical as well as different subtypes within eastern Asian – North American disjunctions. Synthesized with geological and fossil data, phylogenetic and biogeographic results supported the hypothesis that north temperate disjunctions were relicts of the Boretropical flora once widely distributed in the Northern Hemisphere. The disjunct pattern was formed in multiple times in the whole Tertiary, with migration more relatated to Beringia forboth temperate and pantropical taxa rather than North Alantic land bridge. Herbs usually had a divergence time after middle Miocene, while those of woody taxa no later than the Miocene. North temperate disjuncts are also younger than pantropical ones. Long distance dispersal played a similar important role as varcariance. This study also suggested multiple origins of the eastern Asian flora, represented by both ancient Sino-Japanese and young Sino-Himalayan elements. In the Tertiary, large extinction had been occurred in the Northern Hemisphere. The complex disjunct pattern in eastern Asia – North America might directly lead to the complicate origin and source of Sino-Himalayan elements. Morphological stasis or convergence is common in disjunct taxa, which indicates a long stable and similar habitat among relitct floras in the Northern Hemisphere.
语种	中文
公开日期	2011-10-25
页码	205
内容类型	学位论文
源URL	[http://ir.kib.ac.cn/handle/151853/194]
专题	昆明植物研究所_昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	聂泽龙. 东亚—北美间断代表类群的分子生物地理与进化研究[D]. 昆明植物研究所. 中国科学院昆明植物研究所. 2008.

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