North American face flies Old World origins: mitochondrial evidence

Analysis of a 513 base sequence of mitochondrial cytochrome oxidase I gene in Musca autumnalis De Geer (Diptera: Muscidae) from the U.S.A., England, Russia and Kazakhstan confirms that North American flies originated in Western Europe. Flies from the U.S.A., England and southern Russia shared most of their mitochondrial diversities, but face flies from Kazakhstan were substantially dissimilar, suggesting highly restricted gene flow and a species complex within the Palearctic.     

Variation in mitochondrial cytochrome c oxidase subunit I gene in Nezara viridula (Hemiptera: Pentatomidae) from Argentina

Here, we examine the genetic diversity in the agricultural pest Nezara viridula (Linnaeus, 1758 ) from populations of Argentina using mitochondrial cytochrome c oxidase subunit I (COI) gene sequences. The DNA sequence comparisons of 718 base pairs of the COI gene revealed seven haplotypes. The observed total haplotype diversity (Hd) value was of 0.138, and the nucleotide diversity was of 0.00039 and 0.00135 according to π and θ_W, respectively. Eight out of the 10 populations analysed, mostly from soya bean crops, only presented the more frequent haplotype, while 2 haplotypes were found in a mixed culture and 6 haplotypes in a peanut culture. Factors such as differential insecticide applications, as well as the surrounding habitat, and the host plant preference could be related to the genetic diversity differences observed among samples of N. viridula. The analysis of genetic diversity in samples collected in crops treated and non‐treated with insecticides, as well as in samples collected from different seasons, could help to clarify the role of the factors that led to the pattern of genetic diversity detected in this study. The result of a comparative analysis of COI gene sequences among populations from South America, Africa, Asia and Europe was consistent with the hypothesis of an African origin of N. viridula. On the other hand, the haplotypes of Europe were clustered with haplotypes from South America. In addition, specimens from Madeira (west of Europe) shared ancestry with South America and Europe. It has been suggested that a probable route of colonization of America could have been from Western Europe towards the eastern coasts of South America.     

Mitochondrial diversity of Musca domestica housefly populations in the Asian and western Pacific biogeographical regions

Houseflies (Musca domestica L., Diptera: Muscidae) are cosmopolitan, colonizing, and eusynanthropic. Their distribution in the Malaysian archipelago provides an opportunity to study successive waves of colonization and extinction during the Pleistocene and Recent epochs. We scored single-strand conformation polymorphisms (SSCPs) at 16S2 and COII mitochondrial loci in 47 housefly samples from the Australian, Austro-Malayan, Indo-Malayan, Manchurian and Indo-Chinese subregions of Wallace's zoogeographical classification. We discuss the results in light of the Pleistocene vs. post-Pleistocene dispersal and faunal exchange in the Asia-Pacific area. Fourteen haplotypes were detected, of which 10 were confined to a single subregion. No haplotype was ubiquitous and only one was found in four subregions. Population diversity, HS, was greatest in the Indo-Malayan (0.36) and heterogeneous among subregions. The mean subregional diversity was 0.21 +/- 0.03, representing the probability that two randomly chosen flies, from any subregion, had different haplotypes. The hierarchical partition of diversity indicated restricted maternal gene flow among subregions (GRT = 0.60, Nm approximately 0.32). These results suggest long-standing genetic isolation of houseflies in the Malaysian archipelago and support the hypothesis that they dispersed widely during the Pleistocene. Haplotypes common among mainland populations but shared with island groups in low frequencies (<1%) indicate surprisingly little recent gene flow.     

Cytonuclear coadaptation in Drosophila: disruption of cytochrome c oxidase activity in backcross genotypes

Abstract The cytochrome c oxidase enzyme (COX) is comprised of 10 nuclear-encoded subunits and three mito-chondrial-encoded subunits in close physical association in the inner mitochondrial membrane. COX passes electrons from cytochrome c to molecular oxygen and pumps protons into the inner mitochondrial space for ATP production. Selection on nuclear-mitochondrial interactions within species should lead to coadaptation of the proteins comprising this important enzyme. Under this model, there should be relatively little disruption of COX activity when mitochondrial genomes are crossed among strains within species. A more pronounced disruption of activity is expected when the mitochondrial genome is expressed in the nuclear background of a different species. We test these hypotheses in Drosophila using hybridization and backcrossing among lines of D. simulans and D. mauritiana. Disrupted cytonuclear genotypes were constructed using backcrosses between two lines of D. simulans (siI and si II ) that introduced each divergent mitochondrial DNA (mtDNA) into each nuclear background due to maternal inheritance of mtDNA. Similar crosses were used to introduce eachD. simulans mtDNA into the D. mauritiana maI nuclear background. Reconstituted cytonuclear control genotypes were constructed by backcrossing the initial F1 females to males of the maternal genotype. COX enzyme activities were compared among these disrupted and reconstituted backcross genotypes within and between species. The disruption effect on COX activity was restricted to males of interspecific genotypes. These data support the coadaptation hypothesis and are consistent with predictions that the evolution of modifiers of male mitochondrial dysfunction is hindered by the maternal inheritance of mtDNA. New sequence data for nuclear encoded subunits of COX identified amino acids that may play a role in the disruption effect.     

基于线粒体基因Cytb和COI的蝗科中五亚科分子系统发育关系分析（直翅目: 蝗总科）（英文）

本研究基于Cytb 基因和COI基因的部分序列来推断17种蝗虫之间的系统发育关系。这17种蝗虫均采自国内,代表了蝗科(Acrididae)5个亚科：黑蝗亚科(Melanoplinae)、斑腿蝗亚科(Catantopinae)、刺胸蝗亚科(Cyrtacanthacridinae)、斑翅蝗亚科(Oedipodinae)和大足蝗亚科(Gomphocerinae)。采用联合序列方法进行分析,结果显示：Cytb 和COI联合序列长度为1 998 bp,其中A和T总含量为72.13%,G和C总含量为27.87%。联合序列共包含了889个保守位点,1 109个变异位点,在这些变异位点中有838个简约信息位点。系统发生树采用邻接法（NJ）、最大简约法（MP）和最大似然法（ML）进行构建。使用蜢总科的变色乌蜢Erianthus versicolor 和 Erianthus sp. 两个种作为外群。结果表明：大足蝗亚科和斑腿蝗亚科的单系性没有得到支持。斑翅蝗亚科内部各种聚成一个大支,在本研究中该亚科的单系性得到支持,与前人的研究结论相同。大足蝗亚科、斑腿蝗亚科、刺胸蝗亚科和黑蝗亚科这4科关系非常近,可以考虑将其合并为一个亚科。同时,我们发现基于Cytb和COI基因联合序列推断蝗科内各亚科间的系统发生关系并不十分可靠。     

Characterization of microsatellite loci in the house fly,Musca domestica L. (Diptera: Muscidae)

The house fly, Musca domestica L., is a cosmopolitan species with a capacity to transmit human pathogens. Here, we report on the development of polymorphic microsatellite loci for house flies and present preliminary results from four house fly subpopulations from Manhattan, Kansas. Twenty‐four microsatellite loci were isolated and characterized using DNA enriched for repeat sequences. Forty individuals from four locations in Kansas were assayed to identify for polymorphic loci. Eight loci were polymorphic with the number of alleles ranging from three to six.     

Studying the “fly factor” phenomenon and its underlying mechanisms in house flies Musca domestica

The “fly factor” was first discovered >60 years ago and describes the phenomenon that food currently or previously fed on by flies attracts more foraging flies than the same type and amount of food kept inaccessible to flies. Since then, there has been little progress made to understanding this phenomenon. Our objectives were (i) to demonstrate the existence of the fly factor in house flies, Musca domestica and (ii) to study underlying mechanisms that may cause or contribute to the fly factor. In 2‐choice laboratory bioassays, we obtained unambiguous evidence for a fly factor phenomenon in house flies, in that we demonstrated that feeding flies are more attractive to foraging flies than are nonfeeding flies, and that fed‐on food is more attractive to foraging flies than is “clean” food. Of the potential mechanisms (fly excreta, metabolic output parameters [elevated temperature, relative humidity, carbon dioxide]), causing the fly factor, fly feces, and regurgitate do attract foraging flies but none of the metabolic output parameters of feeding flies does. Even though feeding flies produce significantly more CO₂ than nonfeeding flies, elevated levels of CO₂ have no behavior‐modifying effect on flies. Preferential attraction of house flies to fly feces and regurgitate indicates that the flies sense airborne semiochemicals emanating from these sources. Hypothesizing that these semiochemicals are microbe‐produced, future studies will aim at isolating and mass producing these microbes to accumulate semiochemicals for identification.     

Diverging patterns of mitochondrial and nuclear DNA diversity in subarctic black spruce: imprint of a founder effect associated with postglacial colonization

High-latitude ecotonal populations at the species margins may exhibit altered patterns of genetic diversity, resulting from more or less recent founder events and from bottleneck effects in response to climate oscillations. Patterns of genetic diversity were investigated in nine populations of the conifer black spruce (Picea mariana [Mill.] BSP.) in northwestern Québec, Canada, using seed-dispersed mitochondrial (mt) DNA and nuclear (nc) DNA. mtDNA diversity (mitotypes) was assessed at three loci, and ncDNA diversity was estimated for nine expressed sequence tag polymorphism (ESTP) loci. Sampling included populations from the boreal forest and the southern and northern subzones of the subarctic forest-tundra, a fire-born ecotone. For ncDNA, populations from all three vegetation zones were highly diverse with little population differentiation (thetaN = 0.014); even the northernmost populations showed no loss of rare alleles. Patterns of mitotype diversity were strikingly different: within-population diversity and population differentiation were high for boreal forest populations [expected heterozygosity per locus (HE) = 0.58 and thetaM = 0.529], but all subarctic populations were fixed for a single mitotype (HE = 0). This lack of variation suggests a founder event caused by long-distance seed establishment during postglacial colonization, consistent with palaeoecological data. The estimated movement of seeds alone (effective number of migrants per generation, NmM < 2) was much restricted compared to that estimated from nuclear variants, which including pollen movement (NmN > 17). This could account for the conservation of a founder imprint in the mtDNA of subarctic black spruce. After reduction, presumably in the early Holocene, the diversity in ncDNA would have been replenished rapidly by pollen-mediated gene flow, and maintained subsequently through vegetative layering during the current cooler period covering the last 3000 years.     

Molecular evolution of tephritid fruit flies in the genus Bactrocera based on the cytochrome oxidase I gene

Fruit flies of the genus Bactrocera (Diptera: Tephritidae) are one of the major economically important insects in Asia and Australia. Little attention has been given to analyses of molecular phylogenetic relationships among Bactrocera subgenera. By using mitochondrial cytochrome oxidase I gene (COI) sequences, the phylogenetic relationships among four subgenera, Asiadacus, Bactrocera, Hemigymnodacus, and Zeugodacus, were investigated. Nucleotide diversity within subgenera ranged from 11.7 to 12.4%, and the net divergence among subgenera ranged from 11.2 to 15.7%. Phylogenetic trees calculated from both maximum parsimony and neighbor-joining phylogenetic analysis methods were highly congruent in terms of tree topologies. Phylogenetic analysis of mitochondrial COI sequences suggests that tephritid fruit fly species, which attack cucurbit plants, that is, Asiadacus, Hemigymnodacus and Zeugodacus, were more closely related to each other than to fruit fly species of the subgenus Bactrocera, which attack plants of numerous families. Our data supports previous classification of Bactrocera based on morphological characters. However, the phylogenetic tree showed the polyphyletic of fruit flies in subgenus Zeugodacus. Possible causes of speciation among fruit flies species in this genus were also discussed.     

Mitochondrial diversity analysis of Glossina palpalis gambiensis from Mali and Senegal

West African riverine tsetse populations of Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) were investigated for gene flow, inferred from mitochondrial diversity in samples of 69 flies from Senegal and 303 flies from three river drainages in Mali. Four polymorphic mitochondrial loci were scored. Mean haplotype diversities were 0.30 in Mali, 0 in Senegal and 0.18 over both Mali and Senegal. These diversities estimate the probabilities that two randomly chosen tsetse have different haplotypes. Substantial rates of gene flow were detected among flies sampled along tributaries belonging to the river basins of the Senegal, Niger, and Bani in Mali. There was virtually no gene flow between tsetse in Senegal and Mali. No seasonal effects on gene flow were detected. The implications of these preliminary findings for the implementation of area-wide integrated pest management (AW-IPM) programmes against riverine tsetse in West Africa are discussed.     

基于线粒体细胞色素c氧化酶亚基I基因序列的帘蛤科贝类分子系统发育研究

对21种帘蛤科贝类线粒体细胞色素c氧化酶亚基Ⅰ(cytochrome c oxidase subunit I,COI)基因核苷酸序列进行了分析,以探讨这一序列在种质鉴定、分子系统发生研究中的应用价值。测序结果表明,所有物种扩增片段长度均为707 bp(含引物),序列A+T含量(62.4%—67.8%)明显高于G+C含量。物种间共有变异位点379个,其中简约信息位点334个;此区段共编码235个氨基酸,种间共有氨基酸变异位点100个。以COI基因片段序列为标记,用中国蛤蜊(Mactra chinensis)作外群,构建了35种帘蛤科贝类(其中14种贝类COI序列从GenBank下载)的系统发生树,结合拓扑结构分析和序列比对分析,结果表明:支持将短文蛤(Meretrix petechinalis)和丽文蛤(M.lusoria)订为文蛤(M.meretrix)的同物异名的观点,建议将丽文蛤和短文蛤订为文蛤的地理亚种;支持将薄片镜蛤(Dosinia corrugata)和D.angulosa订为2个独立种的观点;认为将波纹巴非蛤(Paphia undulata)和织锦巴非蛤(P.textile)订为2个独立种是合适的。COI基因序列含有丰富的遗传信息,适合作为帘蛤科贝类种群遗传结构和系统发生研究的分子标记。     

Phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit 1 gene from 13 sipunculan genera: intra- and interphylum relationships

Abstract. Sipunculans are a phylum of non-segmented, marine worms. Although they are well characterized morphologically, relationships within the phylum and the relationship of Sipuncula to other spiralian phyla have been strongly debated. I analyzed representatives of 13 of 17 described genera using a 654-bp fragment of the mitochondrial gene, cytochrome c oxidase subunit I, to construct the first intraphylum phylogenetic hypothesis for sipunculans based on molecular sequence data. Within the phylum, tree topologies are loosely congruent with a previously published morphological analysis, except that the monotypic genus Phascolopsis occurred within the Golfingiaformes as a sister group to, or nested within, the Themistidae. Phylogenetic analyses, including 30 sequences from additional invertebrate taxa, suggest that sipunculans are most closely related to the Annelida (including Echiura). A previously proposed sipunculan-molluscan relationship is not supported. While not universally accepted, this hypothesis is consistent with other recent and past data on phylum-level relationships.     

Survey of insect growth regulator (IGR) resistance in house flies (Musca domestica L.) from southwestern Turkey

Insect growth regulators (IGRs) are currently the fastest‐growing class of insecticides, and in Turkey these products represent a new approach to pest control. In recent years, several IGRs were also registered for the control of the house fly, Musca domestica L. (Diptera: Muscidae), in Turkey. A field survey was conducted in the summers of 2006 and 2007 to evaluate resistance to some agriculturally and medically used IGRs on house flies from livestock farms and garbage dumps in the greenhouse production areas (Merkez, Kumluca, Manavgat, and Serik) of Antalya province (Southwestern Turkey). The results of larval feeding assay with technical diflubenzuron, methoprene, novaluron, pyripoxyfen, and triflumuron indicate that low levels (RF<10‐fold) of resistance to the IGRs exist in the house fly populations from Antalya province. Exceptions, however, were two populations, Guzoren and Toptas, from the Kumluca area which showed moderate resistance to diflubenzuron with 11.8‐fold in 2006 and 13.2‐fold in 2007, respectively. We found substantial variation in susceptibility of field‐collected house fly populations from year to year and from product to product. We generally observed an increase in resistance at many localities sampled from 2006 to 2007. The implications of these results to the future use of IGRs for house fly control are discussed. It will be critically important to continue monitoring efforts so that appropriate steps can be taken if resistance levels start to increase.     

Intraspecific genetic variation in Paramecium revealed by mitochondrial cytochrome C oxidase I sequences

Studies of intraspecific genetic diversity of ciliates, such as population genetics and biogeography, are particularly hampered by the lack of suitable DNA markers. For example, sequences of the non-coding ribosomal internal transcribed spacer (ITS) regions are often too conserved for intraspecific analyses. We have therefore identified primers for the mitochondrial cytochrome c oxidase I (COI) gene and applied them for intraspecific investigations in Paramecium caudatum and Paramecium multimicronucleatum. Furthermore, we obtained sequences of the ITS regions from the same strains and carried out comparative sequence analyses of both data sets. The mitochondrial sequences revealed substantially higher variation in both Paramecium species, with intraspecific divergences up to 7% in P. caudatum and 9.5% in P. multimicronucleatum. Moreover, an initial survey of the population structure discovered different mitochondrial haplotypes of P. caudatum in one pond, thereby demonstrating the potential of this genetic marker for population genetic analyses. Our primers successfully amplified the COI gene of other Paramecium. This is the first report of intraspecific variation in free-living protozoans based on mitochondrial sequence data. Our results show that the high variation in mitochondrial DNA makes it a suitable marker for intraspecific and population genetic studies.     

mtDNA中COⅠ分子标记在常见食尸性蝇类鉴定中的应用

死后不同时间,在尸体上出现不同种类食尸性蝇类的演替规律,可用于准确推断死亡时间。传统上仅依据蝇类形态学特征来判断种属,但由于蝇类的形态结构复杂和种间形态差异微小等特点,对蝇类尤其是对蝇类幼虫的种属鉴别很难。因此应用分子生物学方法对食尸性蝇类及其幼虫进行种属鉴定非常重要。本研究主要是利用此方法对我国西部部分地区常见双翅目食尸性蝇类包括：开普黑蝇、大头金蝇、丝光绿蝇及部分卵,铜绿蝇、棕尾别麻蝇及部分幼虫和蛹的线粒体DNA(mtDNA)上细胞色素氧化酶辅酶Ⅰ(COⅠ)中278 bp的基因序列进行鉴别。除个别蝇类如丝光绿蝇与铜绿蝇外,该方法均能有效地将上述食尸性蝇类鉴定到种属水平。在我国,它将成为法医鉴别食尸性蝇类种属的可靠依据。     

Genetic diversity at electrophoretic loci in the house fly,Musca domestica L.

Vertical polyacrylamide gel electrophoresis was used to separate enzyme proteins at 73 putative loci in natural house fly populations sampled in central Iowa. Thirty-nine of the loci were polymorphic (53%). The mean effective number of alleles per polymorphic locus was 1.93 and 1.47 alleles among 68 scored loci. Observed and expected heterozygosities at 34 house fly loci were 0.1628 and 0.1834, respectively. No statistically significant differentiation was detected among nine central Iowa fly populations in 1989 or among nine Iowa and three Minnesota populations in 1990. Journal Paper No. J-14125 of the Iowa Agriculture and Home Economics Experiment Station, Ames. Project No. 2949.     

Correlations between a nuclear and a mitochondrial mRNA of cytochrome c oxidase subunits,enzymatic activity and total mRNA content,in rat tissues

Summary Cytochrome c oxidase (COX), like other multi-subunit components of the respiratory chain, is controlled by both the nuclear and the mitochondrial genome. In order to find wether there is a close relationship between mRNAs encoded by the nucleus and by the mitochondrion, and between these mRNAs and enzyme activity, we compared six rat tissues (ventricle, liver, m. soleus, m. plantaris, and the white and red portions of m. gastrocnemius). We found a tenfold range for COX activity, a tenfold range for the contents of mRNA III (mitochondrial) and mRNA VIc (nuclear), a threefold range for total [poly(A)⁺] mRNA content and a sevenfold range for total RNA content in these tissues. The ratio of mRNA III to mRNA VIc was equal in each tissue, indicating the presence of a mechanism that coordinates the two genomes. There was a good correlation between mRNA content and COX activity (r = 0.78 for VIc, r = 0.77 for 111; p < 0.0001), demonstrating that the expression of this enzyme is mainly under pretranslational control.     

Sequence of mitochondrial DNA cytochrome oxidase II inCryptopygus nanjiensis and Phylogeny of Apterygota

The mitochondrial cytochrome oxidase II (Co II) from four different apterygotens Cryptopygus nanjiensis (Collembola), Neanura latior (Collembola), Gracilentulus maijiawensis (Protura) and Lepidocampa weberi (Diplura) were sequenced. Their A T content, number of nucleotide substitutions, TV/TV ratio, and Tamura-Nei's distance were calculated. A series of phylogenetic trees were constructed by parsimony and distance methods using a crustacean Artemia franciscana as outgroup. Finally the evolutionary trend A T content of CO II genetic divergence and phylogenetic relationship of apterygotan groups were discussed.     

Molecular defects in cytochrome oxidase in mitochondrial diseases

Defects of cytochromec oxidase (COX) show remarkable clinical, biochemical, and genetic heterogeneity. Clinically, there are two main groups of disorders, one dominated by muscle involvement, the other by brain dysfunction. Biochemically, the enzyme defect may be confined to one or a few tissues (reflecting the existence of tissue-specific isozymes) or affect all tissues. Immunologically reactive enzyme protein is decreased in some forms of COX deficiency but not in others. Because COX is encoded both by nuclear and by mitochondrial genes, COX deficiencies may be due to mutations of either genome and may offer useful models to study the communication between nuclei and mitochondria. We have isolated full-length cDNA clones encoding human COX subunits IV, Vb, and VIII and a partial-length clone for subunit Va. These clones are being used as probes to analyze the DNA and RNA of patients with COX deficiency.     

云南中缅树鼩线粒体细胞色素b和D-loop区遗传多样性研究

对3个地方种群的49只样本的线粒体Cyt b基因全序列（1140 bp）及33只样本的控制区D-loop基因区段（745 bp）进行了序列测定。结果表明：Cyt b基因多态性位点有47个,其中单变异位点位点23个,简约信息位点24个。共定义了24个单倍型,其中种群间的共享单倍型有2个（8.33%）,其余均为某个种群所特有,单倍型多样度范围为0.80952（剑川种群）~0.91532（禄劝种群）,核苷酸多样度指数介于0.00326（禄劝种群）~0.00635（剑川种群）之间;D-loop基因多态性位点有18个,其中单变异位点8个,简约信息位点10个。共定义了16个单倍型,无种群间的共享单倍型,单倍型多样度范围为0.76615（禄劝种群）~0.93333（丽江种群）,核苷酸多样度指数介于0.00269（禄劝种群）~0.00583（丽江种群）之间。从各单倍型的TCS网络进化图显示横断山种群位于分支的末端,表现出中缅树鼩由南向北的扩散模式,支持＂岛屿起源＂假说。