Cytochrome Oxidase Subunit II Research Articles

Molecular identification of tsetse fly (Diptera: Glossinidae) species based on mitochondrial DNA (COII and CytB) sequences

Tsetse fly (Diptera: Glossinidae) anti-vector measures are reliant upon accurate identification of species and their subpopulations. Two species were studied, Glossina palpalis palpalis and Glossina morsitans submorsitans using two mitochondrial DNA: cytochrome oxidase subunit II (COII) and cytochrome b (CytB). Sequencing data were used to perform phylogenetic analysis of the two reared species together with other Glossina species’ sequences from the DNA data base. For each gene, members of the same species group, palpalis or morsitans demonstrated a common ancestry and closer relatedness by belonging to one cluster. Within each species group members of the same species clustered together, an indication of common ancestry and relatedness too. Inspite of the few mixed clusters, the pattern produced in the phylogenetic trees can provide a good guide to support any other method of Glossina identification. It was recommended that evaluations be made to validate other genetic markers that can produce better resolutions to identify tsetse fly species using phylogenetic tree. Key words: Trypanosomiasis, Glossina palpalis palpalis, Glossina morsitans submorsitans, cytochrome oxidase II, cytochrome b, neighbour joining tree.

Mitochondrial DNA-based genetic diversity of Anopheles nivipes in North East India

Malaria is a major public health problem in north-east India mainly transmitted by Anopheles baimai and An. minimus while Anopheles nivipes plays an important supportive role. The genetic diversity of An. nivipes in north-east India was investigated by employing two mitochondrial DNA markers namely NADH dehydrogenase 5 (ND5) and cytochrome oxidase sub unit II (COII). High genetic diversity in An. nivipes was observed by the detection of 16 haplotypes among 30 sequences of ND5 gene and 29 haplotypes among 29 COII sequences. Anopheles nivipes of north-east India was significantly differentiated genetically with that of neighboring South-east Asian An. nivipes as revealed by pairwise FST values of 0.127 (p < 0.01) and 0.044 (p < 0.001) for ND5 and COII genes, respectively, suggesting geographical barriers to gene flow in this species between the two geographical areas resulting in significant population structuring.

Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon.

BackgroundChagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU’s. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil.MethodsBlood culture and xenodiagnosis were performed in 36 patients with positive serology for Chagas disease who participated in a serological survey performed in urban and rural areas of Manaus, Amazonas. DNA samples were extracted from the feces of triatomines used for xenodiagnosis, and the nontranscribed spacer of the mini-exon gene and the mitochondrial gene cytochrome oxidase subunit II (COII) were amplified by PCR and sequenced.ResultsBlood culture and xenodiagnosis were negative in 100% of samples; however, molecular techniques revealed that in 13 out of 36 (36%) fecal samples from xenodiagnosis, T. cruzi was characterized as the DTU TcI, and different haplotypes were identified within the same DTU.ConclusionThe DTU TcI, which is mainly associated with acute cases of Chagas disease in the Amazon region, is also responsible for chronic infection in patients from a region in the State of Amazonas.

Anopheles culicifacies sibling species in Odisha, eastern India: First appearance of Anopheles culicifacies E and its vectorial role in malaria transmission

To identify the Anopheles culicifacies sibling species complex and study their vectorial role in malaria endemic regions of Odisha. Mosquitoes were collected from 6 malaria endemic districts using standard entomological collection methods. An.culicifacies sibling species were identified by multiplex polymerase chain reaction (PCR) using cytochrome oxidase subunit II (COII) region of mitochondrial DNA. Plasmodium falciparum (Pf) sporozoite rate and human blood fed percentage (HBF) were estimated by PCR using Pf- and human-specific primers. Sequencing and phylogenetic analysis were performed to confirm the type of sibling species of An.culicifacies found in Odisha. Multiplex PCR detected An.culicifacies sibling species A, B, C, D and E in the malaria endemic regions of Odisha. An.culicifacies E was detected for the first time in Odisha, which was further confirmed by molecular phylogenetics. Highest sporozoite rate and HBF percentage were observed in An.culicifacies E in comparison with other sibling species. An.culicifacies E collected from Nawarangapur, Nuapara and Keonjhar district showed high HBF percentage and sporozoite rates. An.culicifacies B was the most abundant species, followed by An.culicifacies C and E. High sporozoite rate and HBF of An.culicifacies E indicated that it plays an important role in malaria transmission in Odisha. Appropriate control measures against An.culicifacies E at an early stage are needed to prevent further malaria transmission in Odisha.

PCR-RFLP-based method for reliable discrimination of cryptic species within Mecinus janthinus species complex (Mecinini, Curculionidae) introduced in North America for biological control of invasive toadflaxes

Several populations of the stem-mining weevil Mecinus janthinus Germar species complex (Mecinini, Curculionidae), identified based on morphological characteristics, have been introduced in North America for the biological control of invasive toadflaxes of European origin: Linaria vulgaris Miller and L. dalmatica (L.) Miller (Plantaginaceae). According to the mitochondrial cytochrome oxidase subunit II (COII) gene haplotype divergence of Mecinus janthinus species complex, a total of 20 M. janthinus s.s., 3 M. janthinus s.l. of the ‘speciosa’ genotype and 29 M. janthiniformis haplotypes have been recorded across their native range in central and southeastern Europe. A polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) diagnostic assay of COII gene using Hpy188III and MnlI enzyme-mix, was developed for fast and cost-effective discrimination of these morphologically very similar cryptic weevil species. It is shown that digestion generates unique 4-fragment restriction profile in M. janthinus s.s., 2-fragment profile in M. janthiniformis and 3-fragment profile in M. janthinus s.l. ‘speciosa’ group of haplotypes, allowing precise identification of each species or genotype. The proposed method represents a practical tool for fast and accurate identification of the target biocontrol agents and should prevent using inappropriate weevil species in redistribution programs for biological control of invasive toadflax species.

Distribution and genetic diversity of root‐knot nematodes (Meloidogyne spp.) in potatoes from South Africa

A molecular‐based assay was employed to analyse and accurately identify various root‐knot nematodes (Meloidogyne spp.) parasitizing potatoes (Solanum tuberosum) in South Africa. Using the intergenic region (IGS) and the 28S D2–D3 expansion segments within the ribosomal DNA (rDNA), together with the region between the cytochrome oxidase subunit II (COII) and the 16S rRNA gene of the mtDNA, 78 composite potato tubers collected from seven major potato growing provinces were analysed and all Meloidogyne species present were identified. During this study, M. incognita, M. arenaria, M. javanica, M. hapla, M. chitwoodi and M. enterolobii were identified. The three tropical species M. javanica, M. incognita and M. arenaria were identified as the most prevalent species, occurring in almost every region sampled. Meloidogyne hapla and M. enterolobii occurred in Mpumalanga and KwaZulu‐Natal, respectively, while M. chitwoodi was isolated from two growers located within the Free State. Results presented here form part of the first comprehensive surveillance study of root‐knot nematodes to be carried out on potatoes in South Africa using a molecular‐based approach. The three genes were able to distinguish various Meloidogyne populations from one another, providing a reliable and robust method for future use in diagnostics within the potato industry for these phytoparasites.

Genetic population structure of the malaria vector Anopheles baimaii in north-east India using mitochondrial DNA

BackgroundAnopheles baimaii is a primary vector of human malaria in the forest settings of Southeast Asia including the north-eastern region of India. Here, the genetic population structure and the basic population genetic parameters of An. baimaii in north-east India were estimated using DNA sequences of the mitochondrial cytochrome oxidase sub unit II (COII) gene.MethodsAnopheles baimaii were collected from 26 geo-referenced locations across the seven north-east Indian states and the COII gene was sequenced from 176 individuals across these sites. Fifty-seven COII sequences of An. baimaii from six locations in Bangladesh, Myanmar and Thailand from a previous study were added to this dataset. Altogether, 233 sequences were grouped into eight population groups, to facilitate analyses of genetic diversity, population structure and population history.ResultsA star-shaped median joining haplotype network, unimodal mismatch distribution and significantly negative neutrality tests indicated population expansion in An. baimaii with the start of expansion estimated to be ~0.243 million years before present (MYBP) in north-east India. The populations of An. baimaii from north-east India had the highest haplotype and nucleotide diversity with all other populations having a subset of this diversity, likely as the result of range expansion from north-east India. The north-east Indian populations were genetically distinct from those in Bangladesh, Myanmar and Thailand, indicating that mountains, such as the Arakan mountain range between north-east India and Myanmar, are a significant barrier to gene flow. Within north-east India, there was no genetic differentiation among populations with the exception of the Central 2 population in the Barail hills area that was significantly differentiated from other populations.ConclusionsThe high genetic distinctiveness of the Central 2 population in the Barail hills area of the north-east India should be confirmed and its epidemiological significance further investigated. The lack of genetic population structure in the other north-east Indian populations likely reflects large population sizes of An. baimaii that, historically, were able to disperse through continuous forest habitats in the north-east India. Additional markers and analytical approaches are required to determine if recent deforestation is now preventing ongoing gene flow. Until such information is acquired, An. baimaii in north-east India should be treated as a single unit for the implementation of vector control measures.

Cytochrome oxidase II gene "short fragment" applicability in identification of forensically important insects

Correct insect identification is an important issue in the forensic entomological analysis. Short DNA segments can be used to uniquely identify species. In order to be useful as a forensic tool, a short DNA sequence must be not only easily sequenced, but also contains enough variation to generate unique identifiers at either the species or population levels. In the present study, we assessed the applicability of a 189-bp mitochondrial cytochrome oxidase subunit II (COII) gene fragment in identification. We analyzed 53 specimens representing 14 species belong to Sarcophagidae (Sarcophaga carnaria, Sarcophaga dux, Sarcophaga albiceps, Helicophagella melanura, Phallosphaera gravelyi, Boettcherisca peregrina and Wohlfahrtia nuba), Calliphoridae (Lucilia cuprina, Lucilia sericate, Chrysomya megacephala, Chrysomya rufifacie and Chrysomya albiceps) and Muscidae (Musca domestica and Musca autumnalis). This region was amplified using polymerase chain reaction (PCR) followed by direct sequencing of the amplification products. Nucleotide sequence divergences were calculated using the Kimura two- parameter (K2P) distance model and a neighbour-joining (NJ) phylogenetic tree generated. No intraspecific variation within same species (0%), while interspecific variation ranged from 2% to 25%. All specimens were properly assigned into correct species apart from H. melanura and M. autumalis. Although molecular methods are very useful to identify forensically important insect, we propose to use it only in addition to the conventional methods.

Molecular phylogeny of Pamphagidae (Acridoidea, Orthoptera) from China based on mitochondrial cytochrome oxidase II sequences

Phylogenetic relationships of Pamphagidae were examined using cytochrome oxidase subunit II (COII) mtDNA sequences (684 bp). Twenty-seven species of Acridoidea from 20 genera were sequenced to obtain mtDNA data, along with four species from the GenBank nucleotide database. The purpose of this study was analyzing the phylogenetic relationships among subfamilies within Pamphagidae and interpreting the phylogenetic position of this family within the Acridoidea superfamily. Phylogenetic trees were reconstructed using neighbor-joining (NJ), maximum parsimony (MP) and Bayesian inference (BI) methods. The 684 bp analyzed fragment included 126 parsimony informative sites. Sequences diverged 1.0%–11.1% between genera within subfamilies, and 8.8%–12.3% between subfamilies. Amino acid sequence diverged 0–6.1% between genera within subfamilies, and 0.4%–7.5% between subfamilies. Our phylogenetic trees revealed the monophyly of Pamphagidae and three distinct major groups within this family. Moreover, several well supported and stable clades were found in Pamphagidae. The global clustering results were similar to that obtained through classical morphological classification: Prionotropisinae, Thrinchinae and Pamphaginae were monophyletic groups. However, the current genus Filchnerella (Prionotropisinae) was not a monophyletic group and the genus Asiotmethis (Prionotropisinae) was a sister group of the genus Thrinchus (Thrinchinae). Further molecular and morphological studies are required to clarify the phylogenetic relationships of the genera Filchnerella and Asiotmethis.

Phylogeny of Rhus gall aphids (Hemiptera : Pemphigidae) based on combined molecular analysis of nuclear EF1α and mitochondrial COII genes

Abstract Rhus gall aphids (Fordinae : Melaphidini) have a disjunct distribution in East Asia and North America and have specific host plant relationships. Some of them are of economic importance and all species form sealed galls which show great variation in shape, size, structure, and galling‐site. We present a phylogeny incorporating ten species and four subspecies of Rhus gall aphids based on 1694 base pairs of nuclear elongation factor‐1α (EF1α) and mitochondrial cytochrome oxidase subunit II (COII) DNA sequence data. The results suggest that Melaphidini is monophyletic and at the genus level, Schlechtendalia, Nurudea, and Floraphis were each monophyletic. Kaburagia and Meitanaphis were not monophyletic and therefore inconsistent with the current classification. The North American sumac gall aphid, Melaphis rhois, was most closely related to the East Asian Floraphis species, although this was poorly supported. The conservation of gall morphology with respect to aphid phylogeny rather than their host plants suggests that gall morphology is largely determined by the aphids. While there is no evidence of strict co‐speciation between the aphids and their primary host plants, switching between recently diverged host plants may be involved in the speciation process in Melaphidini.

Genetic diversity of the root‐knot nematode Meloidogyne enterolobii and development of a SCAR marker for this guava‐damaging species

The objectives of this work were to evaluate the genetic variability of Meloidogyne enterolobii by molecular markers, and develop species‐specific molecular markers for application in detection. Sixteen M. enterolobii isolates from different geographical regions (Brazil and other countries) and hosts were used in this study. The identification and purification of the populations were carried out based on isoenzyme phenotype. The DNA amplification of the intergenic region (IGS) of the rDNA and of the region between the cytochrome oxidase subunit II (COII) and 16S rRNA genes (mtDNA) produced specific fragments of the expected size for this nematode, i.e. 780 and 705 bp, respectively. Intraspecific variability among the isolates was evaluated with three different neutral molecular markers: AFLP, ISSR and RAPD. The results showed a low level of diversity among the isolates tested, indicating that M. enterolobii is a genetically homogeneous root‐knot nematode species. The RAPD method allowed the identification of a species‐specific RAPD fragment for M. enterolobii. This fragment was cloned and sequenced, and from the sequence obtained, a set of primers was designed and tested. The amplification of a 520‐bp‐long fragment occurred only for the 16 isolates of M. enterolobii and not for the 10 other Meloidogyne species tested. In addition, positive detection was achieved in a single individual female, egg‐mass and second stage juvenile of this nematode. This SCAR species‐specific marker for M. enterolobii represents a new molecular tool to be used in the detection of this nematode from field samples and as a routine diagnostic test for quarantine devices.

Colombian Trypanosoma cruzi major genotypes circulating in patients: Minicircle homologies by cross-hybridization analysis

Here we present compelling evidence of Trypanosoma cruzi genotypes infecting 77 human cases of Chagas disease in Santander Department of Colombia. The patients were clinically studied and classified according to the presence of cardiac symptoms. We describe the distribution of the major T. cruzi genotypes circulating in this area by means of direct PCR analysis of blood samples. PCR was directed to minicircles and amplified DNAs were hybridized using genotype-specific DNA probes. These samples were previously genotyped with miniexon, 24 α rRNA and cytochrome oxidase subunit II (COII) markers. Minicircle DNA analyses were more sensitive than miniexon, 24 α rRNA and CO II genes in detecting infective T. cruzi II (Tc II). Two Tc II genotypes were identified by hybridization using two complementary DNA probes in 27.3% of the patients, with 15.3% using all three markers. These corresponded to 10 cases genotyped only by hybridization. The lineage Tc I, determined by hybridization, was the most prevalent singly or combined with different genotypes (72.7%), and at least three different T. cruzi genotypes were identified. Attempts to find two T. cruzi genotypes Tc I and Tc II in other endemic areas of Colombia revealed that one similar to the most prevalent Tc I genotype was detected in distant geographical areas. A similar Tc II genotype was found in Bolivia and Chile, revealing the great distribution of some ancestral T. cruzi genotypes. We did not detect any association between infective Tc I and Tc II lineages and the severity of the patients’ cardiac symptoms.

Identification of two haplotypes of cytochrome oxidase subunit II (COII) gene of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in southern Mississippi

Coptotermes formosanus Shiraki was accidentally introduced into the United States from Asia. The introduction of the pest has brought significant economic consequences. During the past decade, Mississippi has become a significantly infested state, partly due to the proximity to coastal port cities such as New Orleans. This study was initiated to investigate the origin and infestation route of C. formosanus in southern Mississippi. Twenty-eight colonies (21 colonies from Mississippi, six from Louisiana, one from China) were collected. Sequencing and analysis of 112 sequences revealed 15 haplotypes of cytochrome oxidase subunit II (COII) gene in the world. Two haplotypes of COII were identified in Mississippi. In addition, specific primers were designed and tested differentially to amplify characteristic fragments for verifying and surveying different genotypes of C. formosanus in the future. Of the two haplotypes identified in Mississippi, the GA group was identical to those reported previously in Georgia, Louisiana, Alabama and other infested states. The second haplotype, the AT group, was identified for the first time in southeastern United States. Sequence identity of the AT-group C. formosanus with those reported mainly in southeastern Asian countries provided evidence of at least two introductions of C. formosanus into the United States.

Phylogenetic analysis of the druid flies (Diptera: Schizophora: Clusiidae) based on morphological and molecular data

AbstractIn this paper, the Clusiidae (Diptera: Schizophora) is analyzed phylogenetically using morphological and molecular data sets, and then redefined on the basis of derived morphological characters. The biology and distribution of the Clusiidae are also reviewed, a key is provided to the World genera, the status of the genus Craspedochaeta Czerny is reevaluated and the type of Heterochroa pictipennis Wulp is discussed. Molecular data sets include genomic DNA sequences from the mitochondrial genes COI (cytochrome oxidase subunit I) and COII (cytochrome oxidase subunit II), the large ribosomal nuclear subunit 28S, and the nuclear protein-coding carbomoylphosphate synthase (CPS) domain of CAD (or “rudimentary”). Genes were analyzed separately, in combination with each other, and in combination with a morphological data set. Although individual molecular data sets often provided conflicting phylogenetic signals, the topologies of the cladograms produced from each data set alone or in combination were largely similar. Most genus-level relationships and several basal divergences were unresolved, but Apiochaeta was very strongly and consistently supported as Sobarocephalinae, not Clusiinae. The Clusiinae and Sobarocephalinae are subsequently redefined using an adjusted morphological tree — retaining Apiochaeta in the Sobarocephalinae — that is only slightly longer (8.4%, or seven steps) than the most parsimonious tree. Our results illustrate the benefits of multiple independent data sets for phylogenetic reconstruction in order to verify and refine existing classifications.

Phylogeography of the Iberian populations of Mioscirtus wagneri (Orthoptera: Acrididae), a specialized grasshopper inhabiting highly fragmented hypersaline environments

Phylogeographic studies from western Palaearctic have generally focused on species able to disperse and track their emerging suitable habitats after the last ice age. However, data on species whose biogeographical histories differ from this bulk of Palaearctic fauna are scarce. This is clearly the case of some specialized organisms inhabiting inland hypersaline environments, which are likely to have had a wider distribution range during the late Tertiary and may have persisted through the Pleistocene to the present day only constituting relict populations. In this study, we use partial sequences from two mitochondrial genes [16S rRNA (16S) and cytochrome oxidase subunit II (COII)] to investigate the phylogeography of the Iberian populations of Mioscirtus wagneri (Orthoptera: Acrididae), a specialized grasshopper exclusively inhabiting hypersaline low grounds. Our results show that M. wagneri exhibits a marked phylogeographical structure, forming three main clades which correspond with populations located in north-east, central–south-east and south-west Iberia. These geographical areas did not share any haplotype, indicating that gene flow between them is absent. Nested clade analyses revealed that these lineages have probably evolved in allopatry and data on sequence divergence suggest population fragmentation from the Early Pleistocene. Overall, these results provide a broader perspective on the contribution of historical climate/geological events to biogeographical patterns of organisms currently forming relict populations of great conservation concern. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 623–633.

Limited variation in mitochondrial DNA of maize-associated Ostrinia nubilalis (Lepidoptera: Crambidae) in Russia, Turkey and Slovenia

A sequence analysis of the mitochondrial cytochrome oxidase subunit II (COII) gene in Russian and Turkish maize- associated populations of Ostrinia nubilalis and a Slovenian population of O. nubilalis probably infesting maize revealed little diver- sity. This lack of diversity may have resulted from bottleneck event(s) when the maize-associated population of O. nubilalis expanded from small population(s) in association with the cultivation of maize in Europe ca. 500 years ago. In the genealogy of COII genes obtained in the present and previous studies, Eurasian samples were substantially differentiated from North American samples. Since the North American population of O. nubilalis came from Europe, our finding suggests that there is geographical dif- ferentiation in European maize-associated O. nubilalis, and that maize-associated populations of O. nubilalis expanded multiple times in Europe. Finally, a phylogenetic analysis of the COII gene did not support that O. nubilalis and O. furnacalis are the closest relatives within the O. furnacalis species group.

Mitochondrial COII Introgression into the Nuclear Genome of Gorilla gorilla

Numts are nonfunctional mitochondrial sequences that have translocated into nuclear DNA, where they evolve independently from the original mitochondrial DNA (mtDNA) sequence. Numts can be unintentionally amplified in addition to authentic mtDNA, complicating both the analysis and interpretation of mtDNA-based studies. Amplification of numts creates particular issues for studies on the noncoding, hypervariable 1 mtDNA region of gorillas. We provide data on putative numt sequences of the coding mitochondrial gene cytochrome oxidase subunit II (COII). Via polymerase chain reaction (PCR) and cloning, we obtained COII sequences for gorilla, orangutan, and human high-quality DNA and also from a gorilla fecal DNA sample. Both gorilla and orangutan samples yielded putative numt sequences. Phylogenetically more anciently transferred numts were amplified with a greater incidence from the gorilla fecal DNA sample than from the high-quality gorilla sample. Data on phylogenetically more recently transferred numts are equivocal. We further demonstrate the need for additional investigations into the use of mtDNA markers for noninvasively collected samples from gorillas and other primates.

Relationship Between Chromosomal Races/Subraces in the Brachypterous Grasshopper &lt;I&gt;Podisma sapporensis&lt;/I&gt; (Orthoptera: Acrididae) Inferred from Mitochondrial ND2 and COI Gene Sequences

Podisma sapporensis Shiraki, 1910 (Orthoptera: Acrididae) is distributed on the islands of northern Japan and Far East Russia (Hokkaido, Sakhalin, and Kunashiri), and it exhibits a unique diversity of chromosomal races (X0 and neo-XY) on the island of Hokkaido. To infer the history of geographical isolation and chromosome rearrangements (main races and subraces), we used mito- chondrial DNA (mtDNA) sequence variation in two regions, NADH dehydrogenase subunit 2 (ND2) and cytochrome oxidase subunit II (COII), among 55 individuals representing eight X0/XX and three neo-XY/XX populations. The molecular phylogenetic tree revealed a high level of overall mitochon- drial diversity, but the clustering of the examined population is in most cases closely related to their geographic distribution and associated with chromosomal races and subraces. Together with cyto- genetic observations, we discuss the origin of the polymorphism within the X0 and XY races as well as differences between both northern and eastern races.

TbRGG2, an Essential RNA Editing Accessory Factor in Two Trypanosoma brucei Life Cycle Stages

In the mitochondria of kinetoplastid protozoa, including Trypanosoma brucei, RNA editing inserts and/or deletes uridines from pre-mRNAs to produce mature, translatable mRNAs. RNA editing is carried out by several related multiprotein complexes known as editosomes, which contain all of the enzymatic components required for catalysis of editing. In addition, noneditosome accessory factors necessary for editing of specific RNAs have also been described. Here, we report the in vitro and in vivo characterization of the mitochondrial TbRGG2 protein (originally termed TbRGGm) and demonstrate that it acts as an editing accessory factor. TbRGG2 is an RNA-binding protein with a preference for poly(U). TbRGG2 protein levels are up-regulated 10-fold in procyclic form T. brucei compared with bloodstream forms. Nevertheless, the protein is essential for growth in both life cycle stages. TbRGG2 associates with RNase-sensitive and RNase-insensitive mitochondrial complexes, and a small fraction of the protein co-immunoprecipitates with editosomes. RNA interference-mediated depletion of TbRGG2 in both procyclic and bloodstream form T. brucei leads to a dramatic decrease in pan-edited RNAs and in some cases a corresponding increase in the pre-edited RNA. TbRGG2 down-regulation also results in moderate stabilization of never-edited and minimally edited RNAs. Thus, our data are consistent with a model in which TbRGG2 is multifunctional, strongly facilitating the editing of pan-edited RNAs and modestly destabilizing minimally edited and never-edited RNAs. This is the first example of an RNA editing accessory factor that functions in the mammalian infective T. brucei life cycle stage.

Two mitochondrial lineages occur in the Asian corn borer,Ostrinia furnacalis(Lepidoptera: Crambidae), in Japan

The genealogy and diversity of the mitochondrial cytochrome oxidase subunit II (COII) gene were investigated for Ostrinia furnacalis in Japan. A preliminary examination of mitochondrial lineages in China and the Philippines was also made. Two lineages (A and B) were found in the COII gene. Lineage A was frequent throughout the Japanese main islands (Hokkaido, Honshu, Shikoku and Kyushu), while the frequency of lineage B varied among these islands. No clear patterns of geographical population structure were found. Population genetic features suggested that the O. furnacalis population harboring the lineage A mitochondria expanded in the recent past, while lineage B showed weak signals of a population expansion. It is not clear whether the two lineages of mtDNA evolved in separate or identical geographical regions. We discuss two hypotheses regarding the two lineages of mtDNA: a cryptic race/species hypothesis and a selective sweep hypothesis.