全长rDNA簇在蝽类昆虫生命树构建中的应用前景(昆虫纲,半翅目)

在昆虫纲中,生命树计划正在以目级阶元中的分类单元为单位逐步推进.针对这一大的背景,以及高级阶元和种级阶元分子系统学研究间脱节现状,提出以rDNA簇为一组分子标记、并且在未来高级阶元系统发育研究中将目前选取少量代表类群的做法改为将尽量多的物种包含到一棵系统发育树中的建议.其中首先简要介绍了rDNA簇的结构及其中各分子标记在分子系统学研究中的应用价值,随后以蝽类昆虫为例,有针对性地总结了rDNA簇中不同基因序列已有数据的丰富程度及其在分子系统学研究中的应用情况.首次给出了蝽类昆虫28S rRNA近全长序列的二级结构模型.基于对18S rRNA和28S rRNA二级结构研究所积累的认识,强调了18S rDNA和28S rDNA内部不同区段之间变异模式和应用价值的差异,论证了未来在生命树构建中深化对rDNA簇中各基因进行联合应用的合理性和可行性.     

基于线粒体COⅡ基因的中国蝽科分子系统学研究(半翅目,异翅亚目)

扩增并测定了我国蝽科4亚科8属11种昆虫线粒体COⅡ基因585 bp的序列,对序列的碱基组成、转换颠换、遗传距离等进行分析,探讨了COⅡ基因在该科的分子进化机制.并基于COⅡ基因序列数据,分别采用邻接法(NI)、最大简约法(MP)和贝叶斯推论法(BI)建立蝽科分子系统发育关系.研究结果表明,蝽科昆虫COⅡ基因A T含量平均为71.7%,存在较强的A T含量偏向性,氨基酸的变异率为27.2%;亚科间的遗传距离介于0.168～0.242之间,大于亚科内属种间的遗传距离,蝽科与盾蝽科2外群之间遗传距离最大,两科之间存在明显的间断.分子系统发育树表明,短喙蝽亚科为蝽科中较为原始的类群,分化较早,益蝽亚科与舌盾蝽亚科关系较近,形成一对姐妹群,蝽科中捕食性种类--益蝽亚科是较为特化的类群,它是由植食性种类分化而来.蝽科4亚科间的分子系统发育关系为Phyllocephalinae (Pentatominae (Asopinae Podopinae).     

基于COI基因序列的九种真蝽属昆虫的分子系统学研究(半翅目:蝽科)

通过对真蝽属Pentatoma 9种昆虫线粒体COI基因约798bp的序列进行分子进化分析,并以同蝽科宽铗同蝽Acanthosoma labiduroides为外群,采用最大简约法、最大似然法和邻接法构建了分子系统树,来探讨真蝽属的系统发育关系.研究结果支持褐真蝽群P. semiannulata-group的划分,绿角真蝽Pentatoma viridicornuta应划归到褐真蝽群P. Semiannulata-group;红足真蝽群中的角肩真蝽P. angulata与红足真蝽P. rufipes遗传距离较小,它们是否为1个物种值得关注;真蝽属各群之间的系统发育关系以及是否可分为3个属值得进一步研究.     

盲蝽科昆虫的食性

盲蝽科是半翅目最大的科 ,该科昆虫既有植食性和肉食性类群 ,又有杂食性类群 ,有很大的经济价值。作者综述了盲蝽科昆虫各食性类群中重要种类的寄主范围 ,指出在杂食性盲蝽中作为害虫的天敌作用远远大于对植物的危害 ,同时探讨了盲蝽科昆虫与植物的关系类型及食性的进化。     

水生异翅亚目昆虫化石简介

半翅目异翅亚目昆虫俗称"蝽",该类昆虫出现于三叠纪晚期,最古老的蝽类昆虫大多为水生蝽类。概述了水生蝽类的地质历史,并介绍了划蝽、仰泳蝽、水蝽、负子蝽、三叠蝽及中蝽等代表类群。     

小长蝽线粒体基因组全序列测定与长蝽总科系统发育分析

为了解小长蝽Nysius ericae（Schilling）线粒体基因组结构及长蝽总科的分子系统发育关系。本试验采用Illumina MiSeq测序平台对小长蝽线粒体基因进行测序,对基因组序列进行拼装、注释和特征分析,利用最大似然法和贝叶斯法构建基于12种长蝽总科昆虫线粒体全基因组核苷酸序列的系统发育树。小长蝽线粒体基因组全长为16 330 bp（GenBank登录号：MW465654）,基因组包括13个蛋白编码基因（PCGs）,22个tRNA基因,2个rRNA基因和1段非编码控制区。11个蛋白质编码基因的起始密码子为典型的ATN;cox1,nad4l的起始密码子为TTG。cob的终止密码子为TAG,其余蛋白编码基因的终止密码子为TAA。只有trnS1缺少DHU臂,其余tRNA基因均能形成典型的三叶草结构。12种长蝽总科昆虫线粒体全基因组序列构建的昆虫系统发育树结果显示,小长蝽与Nysius plebeius具有更近的亲缘关系,且与传统形态学分类基本一致。小长蝽线粒体基因组符合长蝽总科线粒体基因组的一般特征。结果表明小长蝽与N. plebeius的亲缘关系更近。     

蝽科部分昆虫细胞色素b基因序列及其系统发育关系的探讨

以线粒体细胞色素b(Cyt b)基因作为分子标记,对蝽科蝽亚科3种、益蝽亚科2种、荔蝽亚科1种、盾蝽亚科2种昆虫进行序列测定,获得Cyt b基因432bp的序列片段,该片段中碱基T、C、A、G的平均含量分别为31．3％、12．4％、37．6％和18．7％,A T平均含量为68．9％,明显高于G C含量(30．1％);密码子第三位点A T含量更高达82．7％。属和种间序列变异大,碱基替换多发生在第三位点。以筛豆龟蝽(Megacopta cribraria)为外群构建系统发育树,结合形态特征与序列变异率,赞同将盾蝽亚科、荔蝽亚科从蝽科划分出来并提升为科的观点,它们之间的系统关系为：盾蝽科与荔蝽科形成姊妹群,较蝽科发育得早;蝽科作为一个单系群,是蝽总科中最为进化的类群。     

蛾蛉类昆虫化石研究进展

蛾蛉类昆虫是脉翅目中化石记录最完整的的类群之一,现生类群蛾蛉、美蛉和山蛉统称为蛾蛉科,但是现生类群与化石类群分类标准的不一致性,为蛾蛉类昆虫化石研究带来较大的困难。本文统计了世界已发现的蛾蛉类昆虫化石属种名录,介绍了蛾蛉类昆虫化石研究历史、地质年代及地理分布、系统发育研究进程,并提出了现今有待解决的问题以及对未来研究的展望。     

鞘喙蝽总科（半翅目）在中国的首次发现

半翅目鞘喙亚目是一类具有重要演化意义的昆虫。该亚目包括三个科：鞘喙蝽科(Peloridiidae)和卡拉蝽科(Karabasiidae)同属于鞘喙蝽总科;原臭虫科(Progonocimicidae)属于原臭虫总科。鞘喙蝽科是唯一的现生类群,孑遗于南半球。卡拉蝽科化石较丰富,但只发现于中亚、西伯利亚和蒙古中生代地层。本文...     

中国缘蝽科部分种类细胞色素b基因序列及系统进化研究

以线粒体细胞色素b(Cyt b)基因作为分子标记,首次对缘蝽科4亚科14种昆虫进行序列测定,获得Cyt b基因412 bp的序列片段,该片段中碱基T、C、A、G的平均含量分别为34.2%、11.4%、35.7 %和18.7 %,A T平均含量为69.9 %,明显高于G C含量(30.1 %).密码子第3位点的A T含量高达82.8%,亚科间序列变异大,有193个核苷酸位点发生变异,碱基替换多发生于第3位点.以筛豆龟蝽为外群构建系统发育树,表明在亚科级关系上,姬缘蝽亚科最原始,蛛缘蝽亚科次之,巨缘蝽亚科和缘蝽亚科亲缘关系较近,为较进化种类.     

MODELING THE MAINTENANCE OF A DEPENDENT LINEAGE SYSTEM: THE INFLUENCE OF POSITIVE FREQUENCY-DEPENDENT SELECTION ON SEX RATIO

In insect societies, worker versus queen development (reproductive caste) is typically governed by environmental factors, but some Pogonomyrmex seed-harvester ants exhibit strict genetic caste determination, resulting in an obligate mutualism between two reproductively isolated lineages. Queens mate randomly with multiple males from each lineage and intralineage crosses produce new queens, whereas interlineage crosses produce workers. Early colony survival is negatively frequency dependent; when lineage frequencies are unequal, queens from the rarer lineage benefit because they acquire more interlineage sperm, and produce more workers. Here we examine theoretically and empirically the effect of relative lineage frequency on sex ratio. We predict that the ratio of inter- to intralineage sperm acquired by queens of each lineage will affect the sex ratio produced at colony maturity. Consistent with model predictions, we found that gyne production in mature colonies was positively frequency dependent, increasing significantly with increasing lineage frequency across 15 populations. Unequal lineage frequencies are common and likely maintained by a complex interplay between an ecological advantage specific to one lineage, and opposing frequency-dependent selection pressures experienced throughout the colonies life-cycle; rare lineage colonies benefit during early colony growth, and common lineage colonies benefit at reproductive maturity.     

THE AGE AND RELATIONSHIPS OF THE MAJOR ANIMAL PHYLA

Given the uncertainties in the fossil record and the paucity of informative morphological characters, there is still considerable uncertainty as to the phylogenetic affinities and times of origins of essentially all of the phyla of animals. A multilocus analysis of amino-acid sequence data for mitochondrial genes suggests that the major triploblast phyla began diverging approximately 630 million years ago. These results support the hypothesis that the so-called Cambrian radiation of animals actually initiated about 100 million years prior to the Cambrian, as the fossil evidence suggests. In addition, phylogenetic analysis supports the monophyly of animals, an early (~900 million years ago) branching off of the cnidarian lineage, the monophyly of deuterostomes and protostomes, and the inclusion of nematodes in the protostome lineage. The results of this study suggest that, with appropriate levels of taxon sampling and a focus on conserved regions of protein-coding sequence, complete mitochondrial genome analysis may be sufficiently powerful to elucidate the genealogical relationships of many of the animal phyla.     

EVOLUTIONARY SIGNIFICANCE OF THE LOSS OF THE CHLOROPLAST-DNA INVERTED REPEAT IN THE LEGUMINOSAE SUBFAMILY PAPILIONOIDEAE

The distribution of a rare chloroplast-DNA structural mutation, the loss of a large inverted repeat, has been determined for 95 species representing 77 genera and 25 of the 31 tribes in the legume subfamily Papilionoideae. This mutation, which is regarded as a derived feature of singular origin within the subfamily, marks a group comprising six temperate tribes, the Galegeae, Hedysareae, Carmichaelieae, Vicieae, Cicereae, and Trifolieae, an assemblage traditionally considered to be monophyletic. This mutation also occurs in the chloroplast genome of Wisteria, a member of the tropical tribe Millettieae whose other members so far surveyed lack the mutation. These new DNA data, together with traditional evidence, support the hypothesis that Wisteria is an unspecialized member of a lineage that gave rise to the temperate tribes marked by the chloroplast-DNA mutation; the probable paraphylesis of Millettieae is revealed. Two other tribes, Loteae and Coronilleae (traditionally regarded as a derived element of the aforesaid temperate tribes) do not possess this chloroplast-DNA structural mutation and, therefore, presumably represent a distinct temperate lineage. This hypothesis is supported by additional evidence from pollen, inflorescence, and root-nodule morphology that suggests that the Loteae and Coronilleae share a more recent ancestry with tropical tribes such as Phaseoleae and Millettieae than with other temperate tribes.     

沅江常德段蚬属贝类的谱系、倍性与性别特征

研究以沅江常德段蚬Corbicula为例, 采用线粒体COⅠ分子标记对其进行谱系构建, 梳理谱系与形态、倍性、性别和遗传多样性之间的关系, 以期为蚬属的系统分类和生殖特征研究提供理论参考。结果显示, 99条COⅠ序列(526 bp)中存在12个单倍型, 共有17个变异位点, 单倍型多样性、核苷酸多样性和平均核苷酸差异数分别为0.599、0.01236和6.503。12个单倍型在系统进化树中被聚为独立的两支(谱系RA和RlcB), 但谱系间壳长、壳高和壳宽没有显著差异(P>0.05)。99个样品中有二倍体50个、三倍体49个、 雌雄同体71个、 雌性21个、 雄性7个。卡方检验发现, 谱系与性别及倍性与性别之间均存在显著的相关性(P<0.05)。谱系RlcB的单倍型数、变异位点数、单倍型多样性、核苷酸多样和平均核苷酸变异数均高于谱系RA。结果表明, 虽然形态、倍性、性别和遗传多样性在谱系RA和RlcB蚬之间存在一定的差异, 但均不足以作为区分两个谱系的生物学特征, 而不同谱系是否为不同的种还有待于进一步的证实。     

A REEXAMINATION OF THE SYSTEMATICS OF THE ACROCHAETIALES (RHODOPHYTA) USING LARGE-SUBUNIT RDNA SEQUENCE DATA

The taxonomic history of the red algal order Acrochaetiales is chaotic. There is no consensus in the literature as to how many genera should be recognized or in the assignment of the over 400 species to these genera. Morphological and anatomical studies have provided a suite of possible characters to delineate genera within this order, but there have been major discrepancies in the assessment and use of these features. The phylogenetic placement of the Acrochaetiales has also been the focus of debate. Once thought to be the most ancestral florideophyte lineage, recent molecular systematic studies have illustrated that this order is a derived lineage closely related to the Nemaliales and Palmariales. Phylogenies using sequences of the small-subunit (SSU) rDNA have strongly supported two very divergent lineages within a possibly polyphyletic Acrochaetiales. The relationships between these two groups and among other closely related rhodophyte orders were not resolved. We have generated large-subunit (LSU) rDNA sequence data for representatives of the Acrochaetiales and related taxa. Distance and parsimony phylogenies based on LSU and combined SSU and LSU data will be presented. The increased phylogenetic signal afforded by this approach will shed light on previous conundrums in the systematics of this group.     

THE PHYLOGENY AND EVOLUTION OF SOME PHACOPID TRILOBITES

Abstract A data matrix of 32 characters, with a total of 132 character states and 48 terminal taxa of phacopid trilobites, was analysed using parsimony. The 108 most parsimonious trees have a length of 301 steps and a consistency index of 0.29. Two major clades were found, one including species referred to Acernaspis and one with species referred to Ananaspis, Paciphacops, Viaphacops , and Phacops . Most homoplasy occurs between the major clades of the trees, rather than within them. The major clades were also analysed separately, resulting in trees with significantly higher consistency indices. We redefine the following supraspecific taxa to make them monophyletic: Acernaspis, Ananaspis , and Paciphacops . In addition, Kainops , new genus, is described for a clade consisting of six taxa previously assigned to Ananaspis and Paciphacops . The evolutionary pattern resulting from our cladogram is compared with the approaches of Campbell and Eldredge, and it is argued that some of the assumptions made by these authors regarding the phylogeny of the group are not valid. The biogeography of the group was also analysed. It is found that phacopids from the Ludlow and older strata are distributed globally, with an emphasis, perhaps due to a large number of suitable localities, on Northern Europe. However, the lineage of phacopines leading up to Phacops is, with some slight exceptions, basically confined to the United States, being entirely absent in Northern Europe. The main phacopine lineage does not re-establish itself geographically until the middle Devonian. Finally, we analysed the evidence for polymorphism in phacopid trilobites, and reject this hypothesis on the basis of stratigraphy and the present cladogram.     

TRACING BACK THE ORIGIN OF THE INDO-PACIFIC MOLLUSC FAUNA: BASAL TRIDACNINAE FROM THE OLIGOCENE AND MIOCENE OF THE SULTANATE OF OMAN

Abstract:  Two new tridacnine species are described from the Chattian and Aquitanian of the Arabian Peninsula. For these, the new names Omanidacna eos gen. et sp. nov. and Tridacna evae sp. nov. are erected. Omanidacna is interpreted as an Oligocene ancestor of Hippopus , being the oldest record of this tridacnine lineage. The Aquitanian Tridacna evae is the first occurrence of the genus Tridacna . These Arabian taxa imply that the modern tridacnine lineages are rooted in the Palaeogene and early Neogene of the East African-Arabian Province, although their Eocene ancestors, such as Byssocardium , are Western Tethyan taxa. During the Neogene they successfully settled the Indo-Polynesian Province and became typical elements of the entire Indo-West Pacific Region. The tridacnines are thus an example of a successive transformation and gradual eastward dispersal of an originally Tethyan element contributing to late Neogene diversity in the Indo-West Pacific.     

FOUNDER EFFECTS AND THE RATE OF MITOCHONDRIAL DNA EVOLUTION IN HAWAIIAN DROSOPHILA

The nearly-neutral-mutation theory predicts that populations with small effective sizes will undergo more rapid molecular evolution than populations with very large effective sizes. In particular, Ohta (1976) predicted that populations of Hawaiian Drosophila that are known to have small population sizes and to experience repeated population bottlenecks due to founder events should show a more rapid rate of molecular evolution relative to the rate of molecular evolution of species with large population sizes such as the continental Drosophila. In this paper we test this prediction by comparing the rate of molecular evolution in two closely related lineages of Hawaiian Drosophila that have experienced very different evolutionary histories. Both lineages belong to the planitibia subgroup of Hawaiian Drosophila. The beta lineage (which includes D. silvestris, D. planitibia, D. differens, and D. hemipeza) has undergone repeated founder events, as evidenced by their geographic distribution and behavioral biology. On the other hand, evidence on geographic distribution and behavior indicates that the alpha lineage (which includes D. melanocephala, D. cyrtaloma, and D. neoperkinsi) has arisen from large ancestral populations without founder effects. The mitochondrial DNA data reveal that, within a lineage, the rate of molecular evolution is rather uniform, while all comparisons between the two lineages show that the rate of molecular evolution in the beta lineage is three times that of the alpha lineage. This analysis strongly supports the predictions made by Ohta.     

松江鲈线粒体DNA控制区结构和遗传多样性分析

为探讨松江鲈(Trachidermus fasciatus Heckel)线粒体控制区特征及其群体遗传结构, 研究测定分析了中国和日本沿海共8个群体的线粒体控制区序列, 分析了其结构特征, 识别出终止序列区(ETAS)、中央保守区(CD)和保守序列区(CSB)的特征序列。遗传多样性分析结果显示: 69个松江鲈个体共检测到47个单倍型, 呈现出核苷酸多样性(0.0079)较低和单倍型多样性(0.978)较高的特点。单倍型邻接关系树和单倍型网络关系图均显示松江鲈分为中国和日本两大世系。遗传分化系数(Fst)和分子方差分析(AMOVA)结果表明, 松江鲈中国群体和日本群体之间存在的遗传差异较显著, 中国沿海各群体之间亦存在着一定程度的遗传差异, 该分化主要由历史环境变动、当代环境因素和自身生态习性等原因造成。     

THE EVOLUTION OF EARLY HOMO: A REPLY TO SCOTT

Scott presents a welcome reply to our article, “A single lineage in early Pleistocene Homo” (Van Arsdale and Wolpoff 2012 ). However, Scott's reply mischaracterizes and fails to directly address the hypothesis of a single lineage that we test. Additionally, the approach taken by Scott fails to replicate the methods used in our analysis. As Scott himself suggests, our null hypothesis of a single evolving lineage in early Homo remains without refutation. Although many evolutionary scenarios might explain the complex pattern of variation present in the early Homo fossil record, the most parsimonious remains that of a single lineage displaying evolutionary change over time.