用叶绿体ndhF和核核糖体ITS序列推断李属(蔷薇科)的系统发育

Sequences of the chloroplast ndhF gene and the nuclear ribosomal ITS regions are employed to reconstruct the phylogeny of Prunus (Rosaceae), and evaluate the classification schemes of this genus. The two data sets are congruent in that the genera Prunus s.l. and Maddenia form a monophyletic group, with Maddenia nested within Prunus. However, the ndhF data set is incongruent with the ITS data supporting two major groups within Prunus one consisting of subgenera Laurocerasus (including Pygeum) and Padus as well as the genus Maddenia and another of subgenera Amygdalus, Cerasus, and Prunus. The ITS data, on the other hand, support a clade composed of subgenera Amygdalus and Prunus and Prunus sect. Microcerasus in addition to a paraphyletic grade of subgenera Laurocerasus and Padus (and the genus Maddenia) taxa. In general, the subgeneric classifications of Prunus s.l. are not supported. The ITS and ndhF phylogenies differ mainly in interspecific relationships and the relative position of the Padus/Laurocerasus group. Both ITS and ndhF data sets suggest that the formerly recognized genus Pygeum is polyphyletic and that the distinction of the subgenera Padus and Laurocerasus is not supported. The biogeographic interactions of the temperate and tropical members in the Padus/Laurocera- sus/Maddenia alliance including Pygeum are shown to be highly dynamic and complex.     

Phylogenetics and biogeography of eastern Asian-North American disjunct genus Pachysandra （Buxaceae） inferred from nucleotide sequences

Pachysandra is an eastern Asian-North American disjtunct genus with three species, two in eastern Asia （Pachysandra axillaris and Pachysandra terminalis） and one in eastern North America （Pachysandra procurnbens）. Although morphological and cytological studies suggest a close affinity of Pprocumbens with P axillaris, molecular data from nuclear and chloroplast DNA regions have provided conflicting signals. In this study, we tested previous phylogenetic hypotheses using sequences of nuclear ribosomal DNA internal transcribed spacers and chloroplast ndhF gene from multiple individuals of each of the three species. We also estimated the time of divergence between eastem Asia and eastern North America. Our results support the morphological and cytological conclusion that P procumbens is more closely related to P axillaris than to P terminalis. The estimated time of divergence of P axillaris and P procumbens was 14.6±5.5 mya, consistent with estimates from many other eastern Asian-North American disjunct genera. The migration of Pachysandra populations from eastern Asia to North America might have occurred by way of the North Atlantic land bridge.     

基于ITS序列探讨珍珠菜属过路黄组的系统关系

测定了紫脉过路黄、临时救和过路黄的nrDNA ITS序列,并分析了珍珠菜属过路黄组17个物种的遗传距离及亲缘关系。结果表明,过路黄组植物的ITS序列长度在620～628间,一致性高达90.59%,种间遗传距离为0.002～0.199。系统发育树表明:(1)紫脉过路黄、临时救和小茄亲缘关系较近;(2)大叶过路黄、落地梅和过路黄亲缘关系较近;(3)山萝过路黄、贯叶过路黄、管茎过路黄、叶头过路黄、峨眉过路黄及三角叶过路黄亲缘关系较近。ITS序列分析结果为组内植物的鉴定、分类及系统进化提供了新的参考。     

基于ITS序列探讨山茶属金花茶组的系统发育关系

测定了分布于我国的 2 2个山茶属金花茶组的种或变种的nrDNAITS区序列 ,它们的序列长度在 476～ 496之间。GC含量都超过了 70 % ,应用Kimura2 模型计算了序列间的分化程度 ,构建了最大简约树、邻接树和最大似然树 ,分析结果表明 :( 1 )淡黄金花茶、毛籽金花茶、陇瑞金花茶、弄岗金花茶、大样金花茶和凹脉金花茶的关系较近 ;( 2 )小瓣金花茶、小花金花茶、薄叶金花茶、多瓣金花茶、夏石金花茶和龙州金花茶的关系较近。ITS区序列分析结果与AFLP分析结果相近     

Toward a global phylogeny of the Brassicaceae

The Brassicaceae is a large plant family (338 genera and 3,700 species) of major scientific and economic importance. The taxonomy of this group has been plagued by convergent evolution in nearly every morphological feature used to define tribes and genera. Phylogenetic analysis of 746 nrDNA internal transcribed spacer (ITS) sequences, representing 24 of the 25 currently recognized tribes, 146 genera, and 461 species of Brassicaceae, produced the most comprehensive, single-locus-based phylogenetic analysis of the family published to date. Novel approaches to nrDNA ITS analysis and extensive taxonomic sampling offered a test of monophyly for a large complement of the currently recognized tribes and genera of Brassicaceae. In the most comprehensive analysis, tribes Alysseae, Anchonieae plus Hesperideae, Boechereae, Cardamineae, Eutremeae, Halimolobeae, Iberideae, Noccaeeae, Physarieae, Schizopetaleae, Smelowskieae, and Thlaspideae were all monophyletic. Several broadly defined genera (e.g., Draba and Smelowskia) were supported as monophyletic, whereas others (e.g., Sisymbrium and Alyssum) were clearly polyphyletic. Analyses of ITS data identified several problematic sequences attributable to errors in sample identification or database submission. Results from parsimony ratchet and Bayesian analyses recovered little support for the backbone of the phylogeny, suggesting that many lineages of Brassicaceae have undergone rapid radiations that may ultimately be difficult to resolve with any single locus. However, the development of a preliminary supermatrix including the combination of 10 loci for 65 species provides an initial estimate of intertribal relations and suggests that broad application of such a method will provide greater understanding of relationships in the family.     

基于ITS和matK序列的兰科沼兰族分子系统研究及二新种(英文)

沼兰族是兰科植物的大族之一,约2000种,除了极地和沙漠地区,全球均有分布.该族植物主要分布在热带地区,尤其在东南亚、热带美洲、非洲以及澳大利亚等地区种类非常丰富.目前,已有关于该族植物形态和分子系统的研究,但有关该族亚族和属间的系统关系尚不清楚,属的界定争议也较大.该文基于核基因片段 ITS 和叶绿体基因片段 mat K 序列,采用最大简约法、最大似然法贝叶斯推理分析法,对现有沼兰族主要属的123种植物和10个外类群植物进行了分子系统学研究.结果表明：沼兰族主要分为3个亚族分支,包括附生的鸢尾兰亚族(Oberoniinae)、地生的羊耳蒜亚族(Liparidinae)和沼兰亚族分支(Crepidium clade).鸢尾兰亚族包括6个属、羊耳蒜亚族分支包括5个属、沼兰亚族分支包括4个属;丫瓣兰亚族(Ypsilorchidinae)应归并为鸢尾兰亚族;Disticholiparis 属与 Stichorkis 属的模式标本相同,应并入 Stichorkis 属;沼兰属(Cre-pidium )和无耳沼兰属(Dienia )的唇瓣结构差异较大,但二者均为单系类群.此外,在收集野外实验材料过程中,发现了2种产自中国西南部和越南北部的沼兰族新种,分别命名为麻栗坡羊耳蒜(Platystyliparis mali-poensis G．D．Tang,X．Y．Zhuang & Z．J．Liu)和秉滔羊耳蒜(Cestichis pingtaoi G．D．Tang,X．Y．Zhuang &Z．J．Liu).