Phylogenetic systematics of the nymphaeales

A cladistic analysis was applied to reveal the phylogenetic relationships among the Nymphaeales. Seventeen out of twenty three characters in gross morphology, anatomy and palynology were analyzed, for their evolutionary polarities. From the results of the present analysis, the phylogenetic status of each genus and their relationships were clarified: 1)Nelumbo is a distinct taxon and is presumed to have originated from an ancestral stock of the Nymphaeales; 2)Ceratophyllum has a close phylogenetic relationship withCabomba; and 3) in the Nymphaeaceaesensu stricto, Nuphar and the remaining genral constitute a monophyletic group. A conclusion obtained from the present analysis was that the following three families should be recognized in the Nymphaeales; Nelumbonaceae Nymphaeaceae, and Ceratophyllaceae. The generaBrasenia andCabomba are traditionally classified in the Nymphaeaceae or in the independent family Cabombaceae. However, they should be included in the family Ceratophyllaceae.     

On the biochemical systematics of selected mammalian taxa: empirical comparison of qualitative and quantitative approaches in the evaluation of protein electrophoretic data

Empirical data sets of Artiodactyla (Antilocapridae, Bovidae, Cervidae, Suidae), Carnivora (Mustelidae) and Rodentia (Sciuridae, Cricetidae, Arvicolidae, Muridae), obtained by horizontal starch el electrophoresis of 15–34 isoenzyme sstems, were used to calculate genetic distances and to construct phylogenetic trees by the following methods: Nei's D (corrected for small sample sizes) - UPGMA, FITCH, KITSCH (out of Felsenstein's PHYLIP-package); Rogers -distance - distance-Wanger tree; maximum likelihood approach (cavalli -Sforza -Edwards ); maximum parsimony method (wagner ); Hennigian cladogram. The results were re-examined using the statisticar methods of jackknife and bootstrap. The following problems became apparent and were studied in more detail: inconstancy of molecular evolutionary rate among taxa, non-uniformity of evolutionary rate among isoenzymes, possible convergence of alloenzymes, different evolutionary histories of taxa (radiations/bottlenecks), methodological influences sample sizes / rare alleles, comparability of data sets). The results show, that many branches of the various phylogenetic trees are fairly constant. The ambiguous position of the remaining OTU's is due to insufficient evidence in the primary data rather than to theroperties of cluster algorithms. However, since these problematic cases are also uncertain in phylogenies based on morphological characters and palaeontological results, even an increased data set may not lead to a cyear decision unless additional taxa of crucial importance are examined. Molecular evolutionary rate among taxa seems to be accelerated in some cases, possibly due to random fixation of different alleles during bottlenecks, when a highly polymorpic ancestral form underwent a series of adaptive radiations. Isoenzymes can be divided into groups with different evolutionary rates. Thus, data sets are only comparable with respect to genetic variability and differentiation, when they contain a similar amount of representatives of each of these categories.     

The role of parsimony,outgroup analysis,and theory of evolution in phylogenetic systematics

It is argued that both the principle of parsimony and the theory of evolution, especially that of natural selection, are essential analytical tools in phylogenetic systematics, whereas the widely used outgroup analysis is completely useless and may even be misleading. In any systematic analysis, two types of patterns of characters and character states must be discriminated which are referred to as completely and incompletely resolved. In the former, all known species are presented in which the characters and their states studied occur, whereas in the latter this is not the case. Dependent on its structure, a pattern of characters and their states may be explained by either a unique or by various conflicting, equally most parsimonious hypotheses of relationships. The so-called permutation method is introduced which facilitates finding the conflicting, equally most parsimonious hypotheses of relationships. The utility of the principle of parsimony is limited by the uncertainty as to whether its application in systematics must refer to the minimum number of steps needed to explain a pattern of characterts and their states most parsimoniously or to the minimum number of evolutionary events assumed to have caused these steps. Although these numbers may differ, the former is usually preferred for simplicity. The types of outgroup analysis are shown to exist which are termed parsimony analysis based on test samples and cladistic type of outgroup analysis. Essentially, the former is used for analysing incompletely resolved patterns of characters and their states, the latter for analysing completely resolved ones. Both types are shown to be completely useless for rejecting even one of various conflicting, equally most parsimonious hypotheses of relationships. According to contemporary knowledge, this task can be accomplished only by employing the theory of evolution (including the theory of natural selection). But even then, many phylogenetic-systematic problems will remain unsolved. In such cases, arbitrary algorithms like those offered by phenetics can at best offer pseudosolutions to open problems. Despite its limitations, phylogenetic systematics is superior to any kind of aphylogenetic systematics (transformed cladistics included) in approaching a (not: the) “general reference system” of organisms.     

蝗虫分子系统学研究进展

本文从遗传多样性、近缘种鉴别以及分子进化和系统发育重建 3个方面综述了蝗虫分子系统学的研究进展。     

叶蝉科昆虫分子系统发育的研究进展

从基因组DNA的提取、研究的基因片段、PCR引物选用、扩增条件以及叶蝉科不同阶元的分子系统发育分析等方面,综述叶蝉科(半翅目:叶蝉科)昆虫分子系统发育的研究进展。目前角顶叶蝉类的研究成果相对较多,大叶蝉亚科次之,其余类群的研究较少或无。线粒体基因与核基因序列联合分析以及线粒体全序列分析以及基因序列与形态数据相结合分析,分子鉴定叶蝉与共生菌之间的协同进化的研究,将是叶蝉分子系统学未来发展的主要研究手段。     

分子系统学研究进展

分子系统学 ( molecular systematics)是近 30年发展起来的一门综合性前沿学科 ,它在分子水平上对生物进行遗传多样性、分类、系统发育和进化等方面的研究 ,其研究结果对于保护生物多样性 (尤其是遗传多样性 ) ,揭示生物进化历程及机理具有十分重要的意义。1　分子系统学的定义及发展简史分子系统学是通过检测生物大分子包含的遗传信息 ,定量描述、分析这些信息在分类、系统发育和进化上的意义 ,从而在分子水平上解释生物的多样性、系统发育及进化规律的一门学科。它以分子生物学、系统学、遗传学、分类学和进化论为理论基础 ,以分子生物学…     

Flavonoid patterns and systematics in Eleusine

A survey of leaf flavonoids was conducted on Eleusine coracana ssp. coracana and ssp. africana, E. indica, E. multiflora, E. tristachya, E. floccifolia, and E. compressa. Twenty phenolic compounds were detected. Those identified were: orientin, isoorientin, vitexin, isovitexin, saponarin, violanthin, lucenin-1, and tricin. The study revealed a general generic flavonoid pattern except for E. compressa, which occupies an isolated position in Eleusine. Flavonoids of the perennial E. floccifolia and the annuals E. multiflora and E. tristachya are markedly different from those of cultivated E. coracana, suggesting that these species are only distantly related to the crop. The morphologically well defined E. coracana—africana—indica group also forms a unit in respect of flavonoids. Subspecies africana exhibits a higher flavonoid similarity to ssp. coracana (finger millet) than does E. indica. The weedy race of ssp. africana usually combines flavonoids of both the wild and domesticated subspecies. The flavonoid pattern of the dedza race of ssp.africana is identical to that of finger millet, suggesting either a direct origin of the crop from this race, or extensive introgression from the crop into ssp. africana. A lack of qualitative differences in flavonoids between cultivated races of finger millet is indicative of the genetic stability of these compounds. The flavonoid data confirms the domestication of finger millet from ssp. africana.     

跳甲亚科系统分类学研究进展

跳甲作为叶甲科Chrysomelidae中最大的一个类群具有重要的经济意义。该文简述了跳甲亚科Alticinae的分类研究历史 ,回顾了世界及中国的研究概况 ,从分类地位、族级阶元的划分、支序系统学及分子系统学等方面综述了跳甲亚科的最新研究进展 ,并简要讨论了存在的问题及研究前景     

Introducing systematics Agenda 2000

Systematics Agenda 2000 is an ambitious initiative emanating from biological systematists in the USA. It proposes an intensive international programme over a 25 year period;-(i) to discover, describe and inventory global species diversity, (ii) to synthesize the resulting data into a predictive classification, and (iii) to develop an appropriate information system to handle the resulting information.     

Alkaloid evolution and angiosperm systematics

The correlation of biosynthetic steps leading to the primary precursors of the shikimate pathway with the distribution of derived alkaloids on dahlgren's system of classification of angiosperm orders suggests that evolution paralleled gradual blocking of these steps. Phenylalanine-derived alkaloids, with the centre of radiation situated in the magnoliales, are of widespread occurrence in angiosperms, an indication of the antiquity of the character. Anthranilic acid-derived alkaloids, with the centre of radiotion in the rutales, are less widespread. Orders in which such alkaloids co-occur with the former biogenetic group are considered to be of more recent origin. Finally, mevalonate-derived iridoid alkaloids, with the centre of radiation in the gentianales, are even less widespread. Orders in which such alkaloids co-occur with the former biogenetic groups should thus be of still more recent origin. These concepts are summarized bg a phylogenetic tree, which illustrates the divergence of three major groups of angiosperm superorders.     

Principles of systematics and the system of bivalves

The systems of the class Bivalvia accepted in recent manuals are discussed. The system proposed by L.A. Nevesskaja, O.A. Skarlato, Ya.I. Starobogatov, and A.G. Eberzin (1971) is substantiated and updated. Morphological characters important for the establishment of taxa of different ranks are listed. Three superorders and 17 orders are established; two orders, which are restricted to the Cambrian and the beginning of the Ordovician, are placed outside the accepted superorders.     

On the information content of characters in comparative morphology and molecular systematics

A review of the fundamental difference between single molecular-sequence positions, or numerical characters, and complex morphological characters is the subject of this study. It has been found that transformation series of single complex structures contain enough information to allow a priori determination of character order and that rooting of a dendrogram is possible without out-group comparison, while trees based on less-informative characters can usually only be rooted with out-group comparison. Furthermore, the quality of total information used is decisive in discriminating between hypotheses of relationships. Numerical methods for the inference of phylogenies have been found to be useful for high numbers of characters that have only a low information content, while the Hennigian procedure seems to be preferable for complex characters.

Zusammenfassung

Ein fundamentaler Unterschied zwischen der einzelnen Sequenzposition oder auch numerischen Merkmalen und komplexen morphologischen Merkmalen ist ihr Informationsgehalt. Merkmalsreihen komplexer Strukturen enthalten meist genügend Information, um a priori die Bestimmung der Lesrichtung zu ermöglichen. Die Feststellung des Ursprunges eines Dendrogramms ist somit ohne kladistischen Außengruppenvergleich möglich, während Bäume (Topologien), die auf wenig informativen Merkmalen beruhen, allgemein nur mit dem kladistischen Außengruppenvergleich 'gewurzelt' werden können. Die Qualität der insgesamt verwendeten Information ist entscheidend für die Wahl zwischen alternativen Verwandtschaftshypothesen. Numerische Methoden der Rekonstruktion der Phylogenese sind nützlich bei Verwendung einer gro β en Zahl informationsarmer Merkmale; das Hennigsche Verfahren ist für komplexe Merkmale vorzuziehen.     

On the information content of characters in comparative morphology and molecular systematics

A review of the fundamental difference between single molecular-sequence positions, or numerical characters, and complex morphological characters is the subject of this study. It has been found that transformation series of single complex structures contain enough information to allow a priori determination of character order and that rooting of a dendrogram is possible without out-group comparison, while trees based on less-informative characters can usually only be rooted with out-group comparison. Furthermore, the quality of total information used is decisive in discriminating between hypotheses of relationships. Numerical methods for the inference of phylogenies have been found to be useful for high numbers of characters that have only a low information content, while the Hennigian procedure seems to be preferable for complex characters.     

Advances in the study of the systematics of Actinidia Lindley

Actinidia (Actinidiaceae) is of economic importance for its edible fruits.Traditional taxonomy divided the genus into four sections,Leiocarpae Dunn,Maculatae Dunn,Strigosae Li,and Stellatae Li.However,phylogenetic studies based on morphology and molecular markers have posed challenges to the four-section scheme.It appears that the natural classification of the genus points to the existence of two groups,one comprising Leiocarpae,and the other Maculatae,Strigosae,and Stellatae.Single- or low-copy genes would probably be useful in untangling the perplexity andthe reticulate evolution of the genus.However,any phylogenetic studies must be firmly based on sound taxonomy and identification.Population sampling throughout the distribution range of the taxa should be carried out in order to study the variation pattern of the morphology and,ultimately,to clarify the confusion existing in some taxa.A combination of morphometrics and molecular data is highly desirable for resolving the uncertainty in Actinidia taxonomy.     

Current status of Kluyveromyces systematics

A brief outline of the current taxonomic status of the genus Kluyveromyces is presented. Noteworthy are the transfer of several former Kluyveromyces species to other genera, the retention of the name Kluyveromyces for K. lactis, K. marxianus, and four related species, and some recent attempts to clarify the variety status of strains assigned to K. lactis.     

Chloroplast pigments and algal systematics

The chloroplast pigments of one typical representative (Pleurochloris magna) and two potential members (clone BSG Sticho and an isolate called Tunis) of the new class Eustigmatophyceae have been examined by modern methods including mass spectrometry. The three cultures all exhibited the same chloroplast pigments: Chlorophyll a, but no b or c, δ-carotene (I), canthaxanthin (II), violaxanthin (IIIa), and esterified vaucheriaxanthin (IVb) plus some free vaucheriaxanthin (IVa). Furanoid rearrangement of the epoxidic carotenoids complicated the analysis. The unique pigment complement hereby indicated for Eustigmatophyceae is clearly different from the pigment distribution patterns reported for Chlorophyceae and Xanthophyceae.     

线粒体DNA序列特点与昆虫系统学研究

昆虫线粒体DNA是昆虫分子系统学研究中应用最为广泛的遗传物质之一。线粒体DNA具有进化速率较核DNA快 ,遗传过程不发生基因重组、倒位、易位等突变 ,并且遵守严格的母系遗传方式等特点。本文概述了mtDNA中的rRNA、tRNA、蛋白编码基因和非编码区的一般属性 ,分析了它们在昆虫分子系统学研究中的应用价值 ,以及应用DNA序列数据来推导分类阶 (单 )元的系统发育关系时 ,基因或DNA片段选择的重要性