斑皮蠹属昆虫COⅠ基因比较及系统学初步研究

对6种斑皮蠹线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)进行比较并对斑皮蠹属系统发育关系进行初步探讨。本研究测定分析了6种斑皮蠹线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ),并采用简约法和贝叶斯推论法构建了斑皮蠹的分子进化树。序列比对分析得到365 bp大小的COⅠ基因片段,其中可变异位点182个(49.9%),保守位点174个(47.7%),转换/颠换的平均值(R值)为0.9,说明此段序列适合于分子进化树。利用不同系统发育重建方法得到的进化树具有相似的拓扑结构,同时结合形态学分类特征对斑皮蠹属昆虫的分子系统进化关系进行探讨。研究显示分子结果与形态分类结果相似。利用COⅠ基因构建的斑皮蠹系统发育树是探讨斑皮蠹系统学的有效方法。     

墨天牛属昆虫COⅠ基因比较及系统学初步研究

【目的】对11种墨天牛线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)进行比较并对墨天牛属系统发育关系进行初步探讨。【方法】本文测定分析了11种墨天牛线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ),并采用简约法和贝叶斯推论法构建了墨天牛属的分子进化树。【结果】序列比对分析得到470 bp大小的COⅠ基因片段,其中可变异位点169个(36.0%),保守位点301个(64.0%),转换/颠换的平均值(R值)为1.03,说明此段序列适合于分子进化树。利用不同系统发育重建方法得到的进化树具有相似的拓扑结构,同时结合形态学分类特征对墨天牛属昆虫的分子系统进化关系进行探讨。结果显示分子结果与形态分类结果相似。【结论】利用COⅠ基因构建的墨天牛属系统发育树是探讨墨天牛分类的有效方法。     

家鸭细胞色素C氧化酶Ⅲ（COⅢ）基因的克隆及序列分析

线粒体是存在于绝大多数真核细胞内的一种基本的、重要的细胞器,是细胞进行氧化磷酸化的场所。不同脊椎动物同源基因序列的比较显示,细胞色素b(Cytb)、细胞色素C氧化酶Ⅰ（COⅠ）、细胞色素C氧化酶Ⅱ（COⅡ）、细胞色素C氧化酶Ⅲ（COⅢ） 基因最保守,同源性最高,ATPase6、ATPase8基因、ND基因变异比较大。本试验以家鸭（家鸭起源于绿头鸭：Anas platyrhynchos）肝脏的线粒体DNA为模板,按照GenBank已经公布的潜鸭族（AF090337）的全序列及其绿头鸭的mtDNA部分序列（L22476、L16770、L22477）设计合成特异引物进行PCR扩增,克隆并测定了线粒体细胞色素C氧化酶Ⅲ亚基（COⅢ）的全序列784bp以及ATPase6基因的3'端和tRNA-Gly基因的5'端序列共934bp。 用DNAStar分析软件对家鸭与GenBank中7种禽类的COⅢ序列进行比较分析,显示家鸭与这些动物的COⅢ基因具有较高的同源性,与同科潜鸭属中的Aythya Americana的相似性 最高为90.6 %,与同目不同科的加拿大雁、小天鹅、白额雁的相似性分别为89%、88.6%、88.6%。根据家鸭与其他7种禽类的COⅢ基因序列相似性所建立的进化树,与传统的分类地位基本吻合。     

线粒体Cyt b基因与昆虫分子系统学研究

细胞色素b(cytochrorrle b,Cyt b)是线粒体13个蛋白质编码基因中结构和功能被研究得最为清楚的基因之一,该基因的进化速度适中,适合研究种内到种间甚至科间的系统发育关系,研究内容涉及种及种下阶元的分类鉴定、种上阶元的系统发育分析、种群的遗传变异和进化研究、分子进化研究等方面,本文对Cyt b基因的分子特点及其在昆虫系统学研究中的应用进行综述。     

线粒体DNA编码细胞色素氧化酶亚基基因的进展

细胞色素氧化酶由13个亚基组成,其中构成级联反应核心的最大3个亚基(COXⅠ,COXⅡ和COXⅢ)由mtDNA编码,其余10个亚基(COⅣ,Ⅴa,Ⅴb,Ⅵa,Ⅵb,Ⅵc,Ⅶa,Ⅶb,Ⅶc,和Ⅷ)均由nDNA编码。COXⅠ亚基与hemea、hemea3、CuB结合,直接参与质子泵过程;COXⅡ亚基与CuA结合,位于线粒体包质面与细胞色素C进行反应;COXⅠП亚基参与氧化还原连接的质子易位过程;其余10个亚基的功能尚不明确。COX是线粒体组装所必需的基因,其表达调控与nDNA和mtDNA相互作用有关。     

基于四个线粒体基因片段的银鱼科鱼类系统发育

银鱼科鱼类是我国重要的经济鱼类,但其属间系统发育关系与属、种的界定尚存争议。研究使用线粒体12S/16S核糖体RNA、细胞色素c氧化酶亚基Ⅰ(COⅠ)基因部分序列以及NADH脱氢酶亚基1全长序列重建银鱼科属间的系统发育。结果显示银鱼科鱼类是单系群,白肌银鱼属在银鱼系统发育的基部,"大银鱼属+新银鱼属"、"间银鱼属+银鱼属"形成两个单系亚群,但日本银鱼属的位置没有很好解决。基于COI基因序列计算的"短吻-陈氏-太湖-近太湖新银鱼复合群"种间遗传距离为0—0.19%、"乔氏-寡齿新银鱼复合群"种间遗传距离为0%。整合研究结果与前人形态、分子证据,详细地讨论了银鱼的属、种分类。     

线粒体DNA序列在半翅目异翅亚目昆虫分子系统学上的应用

随着PCR技术的发展以及大量DNA序列的累积,昆虫分子系统学近年来快速发展。线粒体DNA(mtDNA)序列相对于核内DNA序列进化速率较快,常被用于昆虫的系统发育研究。本文综述了国内外学者利用各种线粒体DNA序列来研究半翅目异翅亚目昆虫系统发育的研究概况。总结发现,COⅠ、COⅡ、12S rDNA、16S rDNA、Cytb、ND1、ND2和ND5等线粒体区段被用于半翅目异翅亚目系统发育的研究,其中以COI、COⅡ、16S rDNA和Cytb应用最广泛,但目前尚缺乏不同分子标记间的联合分析。进一步的研究最好在选定半翅目异翅亚目昆虫的分类阶元(如科间、亚科间、科内属间、种间或种内)后,集中测定线粒体某几个区段的DNA序列,然后进行单一分析和联合分析,并与传统形态学研究结果进行比较,可望全面分析半翅目异翅亚目昆虫的系统发育关系。     

暗纹东方鲀线粒体COⅡ及两侧tRNA基因的克隆和序列分析

用细胞色素氧化酶第二亚基基因(COⅡ)特异性引物对暗纹东方(Takifugu fasciatus)的线粒体DNA(mtDNA)进行PCR扩增,克隆并测定了COⅡ及其侧翼tRNA基因的全序列,结果显示,COⅡ基因691 bp和5′端上游的tRNAAsn基因及3′端下游的tRNALys基因序列共890 bp。用DNA分析软件比较暗纹东方与GenBank中9个目11种鱼类的COⅡ序列,显示暗纹东方与这些鱼类的COⅡ基因具有较高的同源性;其中与同属红鳍东方(T.rubripes)的同源性最高为99.0%。暗纹东方COⅡ基因的核苷酸组成中,A T含量为56%,与其他11种鱼类的A T含量(55%~62%)相近。鱼类COⅡ序列组成对A T核苷酸的偏倚程度比较低。根据暗纹东方与其他11种鱼的COⅡ基因序列同源性所建立的分子进化树,与传统的分类地位基本吻合。推定的tRNA二级结构为典型的三叶草型结构。     

基于细胞色素C氧化酶亚基Ⅰ基因的小蜡螟系统进化分析

【目的】小蜡螟Achroia Grisella Fabricius作为蜂业生产中的主要虫害,为确认它在鳞翅目昆虫中的遗传地位,本研究克隆了小蜡螟细胞色素C氧化酶亚基Ⅰ基因COⅠ,并对其序列进行相关生物信息学分析。【方法】根据NCBI已登录鳞翅目昆虫线粒体基因组mtDNA中COⅠ基因保守序列设计简并引物,以小蜡螟基因组为模板进行PCR,克隆并测序得到小蜡螟mtDNA CO Ⅰ基因序列(GenBank登录号:MF509586)。【结果】对CO Ⅰ基因编码区进行序列分析发现,其翻译的起始码子为TTG,以碱基T作为不完全终止;通过CO Ⅰ基因同源性和遗传距离分析发现,小蜡螟与大蜡螟Galleria mellonella同源性最高且遗传距离最近,分别为88.3%、0.117。系统进化分析发现,小蜡螟与其它鳞翅目昆虫聚为一支,其中螟蛾科昆虫大蜡螟、小蜡螟、米蛾Corcyra cephalonica和梢斑螟Corcyra cephalonica聚在一个小的分支。【结论】小蜡螟与大蜡螟的进化地位最为相近,也说明了利用CO Ⅰ基因可以区分同属不同种的蜡螟,研究结果为了解小蜡螟的遗传背景提供理论基础。     

线粒体DNA序列分析在鳞石蛾科(昆虫纲：毛翅目)成、幼虫联系中的应用

水生昆虫幼虫的种类鉴定是影响水质生物监测准确性的重要因素 ,我国这方面的形态学鉴定资料极其缺乏。本研究测定和分析了 4种鳞石蛾成虫及其疑似幼虫的mtDNA COⅠ、Ⅱ及tRNA基因序列 ,发现鳞石蛾成虫与其疑似幼虫的序列歧异度均 <1% ,属于种内差异 ,由此确认了 4种供试幼虫与其对应成虫的联系。研究表明利用线粒体DNA细胞色素氧化酶基因序列分析鉴定鳞石蛾类幼虫是可行的 ,为加快水生昆虫的幼虫分类研究提供了新途径。     

Molecular systematics and phylogeography of Amazonian poison frogs of the genus Dendrobates

The study of Amazonian biodiversity requires detailed knowledge of the phylogenetic relationships of closely related taxa distributed across Amazonia. The Amazonian poison frogs of the genus Dendrobates have undergone many taxonomic revisions, but the phylogenetic relationships within this group remain poorly understood. Most previous classifications were based on morphology and skin toxin analyses, with limited use of DNA sequence data. Using mtDNA sequence data from four gene regions (cytochrome b, cytochrome oxidase I, 16S rRNA, and 12S rRNA), we present a molecular phylogenetic analysis of the evolutionary relationships within a representative group of Amazonian Dendrobates. We use the resulting phylogenetic hypothesis to investigate different biogeographic hypotheses concerning genetic divergence and species diversity in Amazonia. The results of the analysis support the presence of ancient paleogeographic barriers to gene flow between eastern and western Amazonia, and indicate substantial genetic divergence between species found in the northern and southern regions of western Amazonia.     

Evolution of ecological traits and wing morphology in Hemileuca (Saturniidae) based on a two-gene phylogeny

We present a molecular phylogeny for the genus Hemileuca (Saturniidae), based on 624 bp of mitochondrial cytochrome oxidase I (COI) and 932 bp of the nuclear gene elongation factor 1 alpha (EF1alpha). Combined analysis of both gene sequences increased resolution and supported most of the phylogenetic relationships suggested by separate analysis of each gene. However, a maximum parsimony (MP) model for just COI sequence from one sample of most taxa produced a phylogeny incongruent with EF1alpha and combined dataset analyses under either MP or ML models. Time of year and time of day during which adult moths fly corresponded strongly with the phylogeny. Although most Hemileuca are diurnal, ancestral Hemileuca probably were nocturnal, fall-flying insects. The two-gene molecular phylogeny suggests that wing morphology is frequently homoplastic. There was no correlation between the primary larval hostplants and phylogenetic placement of taxa. No phylogenetic pattern of specialization was evident for single hostplant families across the genus. Our results suggest that phenological behavioral characters may be more conserved than the wing morphology characters that are more commonly used to infer phylogenetic relationships in Lepidoptera. Inclusion of a molecular component in the re-evaluation of systematic data is likely to alter prior assumptions of phylogenetic relationships in groups where such potentially homoplastic characters have been used.     

Molecular systematics of cytochrome oxidase I and 16S from Neochlamisus leaf beetles and the importance of sampling.

If a gene tree is to be judiciously used for inferring the histories of closely related taxa, (1) its topology must be sufficiently resolved and robust that noteworthy phylogenetic patterns can be confidently documented, and (2) sampling of species, populations, and pertinent biological variation must be sufficiently broad that otherwise misleading sources of genetic variation can be detected. These principles are illustrated by the complex gene tree of Neochlamisus leaf beetles that I reconstructed using 90,000 bp of cytochrome oxidase I (COI) and 16S mitochondrial DNA (mtDNA) sequences from over 100 specimens. Cytochrome oxidase I haplotypes varied up to 25.1% within Neochlamisus and up to 11.1% within the gibbosus species group, while exhibiting very low A + T bias for insect mtDNA (63%), low transition saturation, and conservative patterns of amino acid variation. 16S exhibited lower sequence divergences and greater A + T bias and transition saturation than COI, and substitutions were more constrained in stems than in loops. Comparisons with an earlier study of Ophraella leaf beetles highlighted conservative and labile elements of molecular evolution across genes and taxa. Cytochrome oxidase I parsimony and neighbor-joining analyses strongly supported a robust mtDNA genealogy that revealed the monophyly of Neochlamisus and of the gibbosus species group. Phylogeographic relationships suggested that the eastern U.S. gibbosus group derives from southwestern velutinus group ancestors. Haplotypes from individual velutinus group species clustered monophyletically, as expected. However, haplotypes from each of several gibbosus group taxa were polyphyletically distributed, appearing in divergent parts of the tree. 16S provided a less-resolved gibbosus group topology that was congruent with the COI tree and corroborated patterns of mitochondrial polyphyly. By subsampling haplotypes corresponding to particular species, populations, and ecological variants of gibbosus group taxa, I demonstrate that recovered topologies and genetic distances vary egregiously according to sampling regime. This study thus documents the potentially dire consequences of inadequate sampling when inferring the evolutionary history of closely related and mitochondrially polyphyletic taxa.     

An ancient tripartite symbiosis of plants, ants and scale insects

In the Asian tropics, a conspicuous radiation of Macaranga plants is inhabited by obligately associated Crematogaster ants tending Coccus (Coccidae) scale insects, forming a tripartite symbiosis. Recent phylogenetic studies have shown that the plants and the ants have been codiversifying over the past 16-20 million years (Myr). The prevalence of coccoids in ant-plant mutualisms suggest that they play an important role in the evolution of ant-plant symbioses. To determine whether the scale insects were involved in the evolutionary origin of the mutualism between Macaranga and Crematogaster, we constructed a cytochrome oxidase I (COI) gene phylogeny of the scale insects collected from myrmecophytic Macaranga and estimated their time of origin based on a COI molecular clock. The minimum age of the associated Coccus was estimated to be half that of the ants, at 7-9Myr, suggesting that they were latecomers in the evolutionary history of the symbiosis. Crematogaster mitochondrial DNA (mtDNA) lineages did not exhibit specificity towards Coccus mtDNA lineages, and the latter was not found to be specific towards Macaranga taxa, suggesting that patterns of associations in the scale insects are dictated by opportunity rather than by specialized adaptations to host plant traits.     

Utility of the mitochondrial cytochrome oxidase II gene for resolving relationships among black flies (Diptera: simuliidae)

The complete mitochondrial cytochrome oxidase II gene was sequenced from 17 black flies, representing 13 putative species, and used to infer phylogenetic relationships. A midge (Paratanytarsus sp.) and three mosquitoes (Aedes aegypti, Anopheles quadrimaculatus, and Culex quinquefasciatus) were used as outgroup taxa. All outgroup taxa were highly divergent from black flies. Phylogenetic trees based on weighted parsimony (a priori and a posteriori), maximum likelihood, and neighbor-joining (log-determinant distances) differed topologically, with deeper nodes being the least well-supported. All analyses supported current classification into species groups but relationships among those groups were poorly resolved. The majority of phylogenetic signal came from closely related sister taxa. The CO-II gene may be useful for exploring relationships at or below the subgeneric level, but is of questionable value at higher taxonomic levels. The weighting method employed gave phylogenetic results similar to those reported by other authors for other insect CO-II data sets. A best estimate of phylogenetic relationships based on the CO-II gene is presented and discussed in relation to current black fly classification.     

A molecular phylogeny of the Cephinae (Hymenoptera, Cephidae) based on mtDNA COI gene: a test of traditional classification

Cephinae is traditionally divided into three tribes and about 24 genera based on morphology and host utilization. There has been no study testing the monophyly of taxa under a strict phylogenetic criterion. A molecular phylogeny of Cephinae based on a total of 68 sequences of mtDNA COI gene, representing seven genera of Cephinae, is reconstructed to test the traditional limits and relationships of taxa. Monophyly of the traditional tribes is not supported. Monophyly of the genera are largely supported except for Pachycephus. A few host shift events are suggested based on phylogenetic relationships among taxa. These results indicate that a more robust phylogeny is required for a more plausible conclusion. We also report two species of Cephus for the first time from Turkey.     

Phylogenetic analysis of the genus Cheilosia (Diptera, Syrphidae) using mitochondrial COI sequence data

The genus Cheilosia is one of the most diverse and speciose genera of Syrphidae (Diptera). The phylogenetic relationships of the hoverfly genus Cheilosia was investigated for the first time using molecular data. The mitochondrial protein-coding gene cytochrome c oxidase subunit I (COI) was chosen for sequencing; 1341 characters were obtained for 24 ingroup taxa and these were analyzed with parsimony. The monophyly of the genus Cheilosia was well supported. Current taxonomic division of Cheilosia into two subgenera (sg. Nigrocheilosia and sg. Neocheilosia) and most nonformalized species groups based on morphology were supported by the monophyletic groups identified in the molecular analysis. The phylogenetic informativeness of COI in resolving the subtribal relationships within the tribe Cheilosiini remains ambiguous.     

Phylogenetic relationships of Nembrothinae (Mollusca: Doridacea: Polyceridae) inferred from morphology and mitochondrial DNA

Within the Polyceridae, Nembrothinae includes some of the most striking and conspicuous sea slugs known, although several features of their biology and phylogenetic relationships remain unknown. This paper reports a phylogenetic analysis based on partial sequences of two mitochondrial genes (cytochrome c oxidase subunit I and 16S rRNA) and morphology for most species included in Nembrothinae. Our phylogenetic reconstructions using both molecular and combined morphological and molecular data support the taxonomic splitting of Nembrothinae into several taxa. Excluding one species (Tambja tentaculata), the monophyly of Roboastra was supported by all the phylogenetic analyses of the combined molecular data. Nembrotha was monophyletic both in the morphological and molecular analyses, always with high support. However, Tambja was recovered as para- or polyphyletic, depending on the analysis performed. Our study also rejects the monophyly of "phanerobranch" dorids based on molecular data.     

黄河裸裂尻鱼细胞色素C氧化酶Ⅰ、Ⅱ和Ⅲ亚基基因的克隆及序列特征分析

采用RT-PCR技术克隆获得了黄河裸裂尻鱼(Schizopygopsis pylzovi)CO Ⅰ、Ⅱ、Ⅲ基因的编码序列,并对此进行了初步分析.结果表明,黄河裸裂尻鱼CO I基因全长为1 551 bp,开放阅读框(ORF)由基因全长组成,编码516个氨基酸;COⅡ基因全长为691 bp,开放阅读框为690 bp,编码2...