Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| a re-examination of wolbachia-induced cytoplasmic incompatibility in california drosophila simulans. | in california drosophila simulans, the maternally inherited riverside strain wolbachia infection (wri) provides a paradigm for rapid spread of wolbachia in nature and rapid evolutionary change. wri induces cytoplasmic incompatibility (ci), where crosses between infected males and uninfected females produce reduced egg-hatch. the three parameters governing wri infection-frequency dynamics quantify: the fidelity of maternal transmission, the level of cytoplasmic incompatibility, and the relative f ... | 2011 | 21799900 |
| desiccation resistance and mating behaviour in laboratory populations of drosophila simulans originating from the opposing slopes of lower nahal oren (israel). | lower nahal oren in northern israel, often referred to as 'evolution canyon', has been proposed as a microscale model site for ecological evolution. however, conflicting stress resistance and mating assay results contribute to controversy over the nahal oren model. in this study, we further tested the nahal oren model, while extending its focus from drosophila melanogaster to its sister species, drosophila simulans. using fly populations derived from the opposing canyon slopes and acclimated to ... | 2011 | 21696478 |
| inter-island divergence within drosophila mauritiana, a species of the d. simulans complex: past history and/or speciation in progress? | speciation with gene flow may be more common than generally thought, which makes detailed understanding of the extent and pattern of genetic divergence between geographically isolated populations useful. species of the drosophila simulans complex provide a good model for speciation and evolutionary studies, and hence understanding their population genetic structure will increase our understanding of the context in which speciation has occurred. here, we describe genetic diversity and genetic dif ... | 2011 | 21599771 |
| does positive selection drive transcription factor binding site turnover? a test with drosophila cis-regulatory modules. | transcription factor binding site(s) (tfbs) gain and loss (i.e., turnover) is a well-documented feature of cis-regulatory module (crm) evolution, yet little attention has been paid to the evolutionary force(s) driving this turnover process. the predominant view, motivated by its widespread occurrence, emphasizes the importance of compensatory mutation and genetic drift. positive selection, in contrast, although it has been invoked in specific instances of adaptive gene expression evolution, has ... | 2011 | 21572512 |
| rapid rise and fall of selfish sex-ratio x chromosomes in drosophila simulans: spatiotemporal analysis of phenotypic and molecular data. | sex-ratio drive, which has been documented in several drosophila species, is induced by x-linked segregation distorters. contrary to mendel's law of independent assortment, the sex-ratio chromosome (x(sr)) is inherited by more than half the offspring of carrier males, resulting in a female-biased sex ratio. this segregation advantage allows x(sr) to spread in populations, even if it is not beneficial for the carriers. in the cosmopolitan species d. simulans, the paris sex-ratio is caused by rece ... | 2011 | 21498605 |
| females with a mutation in a nuclear-encoded mitochondrial protein pay a higher cost of survival than do males in drosophila. | males and females age at different rates in a variety of species, but the mechanisms underlying the difference is not understood. in this study, we investigated sex-specific costs of a naturally occurring mildly deleterious deletion (dtrp85, dval86) in cytochrome c oxidase subunit 7a (cox7a) in drosophila simulans. we observed that females and males homozygous for the mutation had 30% and 26% reduced cox activity, respectively, compared with wild type. furthermore, 4-day-old females had 34%-42% ... | 2011 | 21498433 |
| drosophila genomes and the development of affordable molecular markers for species genotyping. | the recent completion of genome sequencing of 12 species of drosophila has provided a powerful resource for hypothesis testing, as well as the development of technical tools. here we take advantage of genome sequence data from two closely related species of drosophila, drosophila simulans and drosophila sechellia, to quickly identify candidate molecular markers for genotyping based on expected insertion or deletion (indel) differences between species. out of 64 candidate molecular markers select ... | 2011 | 21491976 |
| local adaptation of stress related traits in drosophila buzzatii and drosophila simulans in spite of high gene flow. | we addressed the question if local adaptation to a thermal gradient is possible in spite of a high gene flow among closely spaced populations of two species of drosophila from the island of la gomera (canary islands). variation in multiple traits related to stress resistance in different life stages was measured in both species in flies collected from five localities at different altitudes and thereby with different climatic conditions. based on microsatellite loci, the populations were not gene ... | 2009 | 21462416 |
| functional conservatism among drosophila simulans flies experiencing different thermal regimes and mitochondrial dna introgression. | drosophila simulans possesses three different mitochondrial haplotypes (sii, ii and iii) that are nonrandomly geographically subdivided with a 3% interhaplogroup variation. the aim of this study was to determine whether perturbation of mitochondrial metabolism and ros management by temperature variation and mtdna introgression would influence the development of aerobic capacity and the intensity of oxidative stress in d. simulans at different ages. environmental temperature divergences during de ... | 2011 | 21462313 |
| thermal sensitivity of mitochondrial functions in permeabilized muscle fibers from two populations of drosophila simulans with divergent mitotypes. | in ectotherms, the external temperature is experienced by the mitochondria, and the mitochondrial respiration of different genotypes is likely to change as a result. using high-resolution respirometry with permeabilized fibers (an in situ approach), we tried to identify differences in mitochondrial performance and thermal sensitivity of two drosophila simulans populations with two different mitochondrial types (siii and siiii) and geographical distributions. maximal state 3 respiration rates obt ... | 2011 | 21451139 |
| population transcriptomics: insights from drosophila simulans, drosophila sechellia and their hybrids. | sequence differentiation has been widely studied between populations and species, whereas interest in expression divergence is relatively recent. using microarrays, we compared four geographically distinct populations of drosophila simulans and a population of drosophila sechellia, and interspecific hybrids. we observed few differences between populations, suggesting a slight population structure in d. simulans. this structure was observed in direct population comparisons, as well as in interspe ... | 2011 | 21424276 |
| wolbachia infections in anopheles gambiae cells: transcriptomic characterization of a novel host-symbiont interaction. | the endosymbiotic bacterium wolbachia is being investigated as a potential control agent in several important vector insect species. recent studies have shown that wolbachia can protect the insect host against a wide variety of pathogens, resulting in reduced transmission of parasites and viruses. it has been proposed that compromised vector competence of wolbachia-infected insects is due to up-regulation of the host innate immune system or metabolic competition. anopheles mosquitoes, which tran ... | 2011 | 21379333 |
| pervasive adaptive protein evolution apparent in diversity patterns around amino acid substitutions in drosophila simulans. | in drosophila, multiple lines of evidence converge in suggesting that beneficial substitutions to the genome may be common. all suffer from confounding factors, however, such that the interpretation of the evidence-in particular, conclusions about the rate and strength of beneficial substitutions-remains tentative. here, we use genome-wide polymorphism data in d. simulans and sequenced genomes of its close relatives to construct a readily interpretable characterization of the effects of positive ... | 2011 | 21347283 |
| cytoplasmic incompatibility in drosophila simulans: evolving complexity. | 1996 | 21237786 | |
| genetic mapping of adaptive wing size variation in drosophila simulans. | many ecologically important traits exhibit latitudinal variation. body size clines have been described repeatedly in insects across multiple continents, suggesting that similar selective forces are shaping these geographical gradients. it is unknown whether these parallel clinal patterns are controlled by the same or different genetic mechanism(s). we present here, quantitative trait loci (qtl) analysis of wing size variation in drosophila simulans. our results show that much of the wing size va ... | 2011 | 21157499 |
| comparative analysis of transposable elements in the melanogaster subgroup sequenced genomes. | transposable elements (tes) are indwelling components of genomes, and their dynamics have been a driving force in genome evolution. although we now have more information concerning their amounts and characteristics in various organisms, we still have little data from overall comparisons of their sequences in very closely-related species. while the drosophila melanogaster genome has been extensively studied, we have only limited knowledge regarding the precise te sequences in the genomes of the r ... | 2011 | 21156200 |
| fine-scale genetic mapping of a hybrid sterility factor between drosophila simulans and d. mauritiana: the varied and elusive functions of "speciation genes". | hybrid male sterility (hms) is a usual outcome of hybridization between closely related animal species. it arises because interactions between alleles that are functional within one species may be disrupted in hybrids. the identification of genes leading to hybrid sterility is of great interest for understanding the evolutionary process of speciation. in the current work we used marked p-element insertions as dominant markers to efficiently locate one genetic factor causing a severe reduction in ... | 2010 | 21144061 |
| early life benefits and later life costs of a two amino acid deletion in drosophila simulans. | linking naturally occurring genotypic variation to the organismal phenotype is critical to our understanding of, and ability to, model biological processes such as adaptation to novel environments, disease, and aging. rarely, however, does a simple mutation cause a single simple observable trait. rather it is more common for a mutation to elicit an entangled web of responses. here, we employ biochemistry as the thread to link a naturally occurring two amino acid deletion in a nuclear encoded mit ... | 2011 | 21143473 |
| evolution and inheritance of early embryonic patterning in drosophila simulans and d. sechellia. | pattern formation in drosophila is a widely studied example of a robust developmental system. such robust systems pose a challenge to adaptive evolution, as they mask variation that selection may otherwise act upon. yet we find variation in the localization of expression domains (henceforth "stripe allometry") in the pattern formation pathway. specifically, we characterize differences in the gap genes giant and kruppel, and the pair-rule gene even-skipped, which differ between the sibling specie ... | 2011 | 21121913 |
| male attractiveness, fertility and susceptibility to oxidative stress are influenced by inbreeding in drosophila simulans. | inbreeding frequently leads to inbreeding depression, a reduction in the trait values of inbred individuals. inbreeding depression has been documented in sexually selected characters in several taxa, and while there is correlational evidence that male fertility is especially susceptible to inbreeding depression, there have been few direct experimental examinations of this. here, we assessed inbreeding depression in male fertility and a range of other male fitness correlates in drosophila simulan ... | 2011 | 21091568 |
| the effect of developmental temperature on the genetic architecture underlying size and thermal clines in drosophila melanogaster and d. simulans from the east coast of australia. | body size and thermal tolerance clines in drosophila melanogaster occur along the east coast of australia. however the extent to which temperature affects the genetic architecture underlying the observed clinal divergence remains unknown. clinal variation in these traits is associated with cosmopolitan chromosome inversions that cline in d. melanogaster. whether this association influences the genetic architecture for these traits in d. melanogaster is unclear. drosophila simulans shows linear c ... | 2011 | 21091469 |
| infection with the wmel and wmelpop strains of wolbachia leads to higher levels of melanization in the hemolymph of drosophila melanogaster, drosophila simulans and aedes aegypti. | introduction of the life-shortening strain of wolbachia pipientis, wmelpop, into the key dengue vector, aedes aegypti, and the anti-pathogen effects in wolbachia-infected hosts highlights the need for more research into its interactions with its original host, drosophila melanogaster, and the novel mosquito host. the visual difference in darkness between the eggs of wmelpop wolbachia-infected and uninfected mosquito hosts after egg deposition led to further investigation into melanization levels ... | 2010 | 21075139 |
| multiple hybridization events between drosophila simulans and drosophila mauritiana are supported by mtdna introgression. | the study of speciation has advanced considerably in the last decades because of the increased application of molecular tools. in particular, the quantification of gene flow between recently diverged species could be addressed. drosophila simulans and drosophila mauritiana diverged, probably allopatrically, from a common ancestor approximately 250,000 years ago. however, these species share one mitochondrial dna (mtdna) haplotype indicative of a recent episode of introgression. to study the exte ... | 2010 | 20958812 |
| cost of a naturally occurring two-amino acid deletion in cytochrome c oxidase subunit 7a in drosophila simulans. | this study aimed to determine whether a naturally occurring (deltatrp85, deltaval86) deletion from a protein subunit of cytochrome c oxidase (complex iv) influenced cytochrome c oxidase activity, mrna expression levels of electron transport chain genes, and aspects of adult female fitness in the fly drosophila simulans. we modeled the tertiary structure of d. simulans cox7a containing the deletion by homology to the bovine cox7a structure and predicted that it would decrease the function of comp ... | 2010 | 20698788 |
| introgression of drosophila simulans nuclear pore protein 160 in drosophila melanogaster alone does not cause inviability but does cause female sterility. | we have been analyzing genes for reproductive isolation by replacing drosophila melanogaster genes with homologs from drosophila simulans by interspecific backcrossing. among the introgressions established, we found that a segment of the left arm of chromosome 2, int(2l)s, carried recessive genes for hybrid sterility and inviability. that nuclear pore protein 160 (nup160) in the introgression region is involved in hybrid inviability, as suggested by others, was confirmed by the present analysis. ... | 2010 | 20647504 |
| r2 dynamics in triops cancriformis (bosc, 1801) (crustacea, branchiopoda, notostraca): turnover rate and 28s concerted evolution. | the r2 retrotransposon is here characterized in bisexual populations of the european crustacean triops cancriformis. the isolated element matches well with the general aspects of the r2 family and it is highly differentiated from that of the congeneric north american triops longicaudatus. the analysis of 5' truncations indicates that r2 dynamics in t. cancriformis populations show a high turnover rate as observed in drosophila simulans. for the first time in the literature, though, individuals h ... | 2010 | 20628416 |
| artificial triple wolbachia infection in aedes albopictus yields a new pattern of unidirectional cytoplasmic incompatibility. | obligately intracellular wolbachia bacteria infect numerous invertebrates and often manipulate host reproduction to facilitate the spread of infection. an example of reproductive manipulation is wolbachia-induced cytoplasmic incompatibility (ci), which occurs commonly in insects. this ci has been the focus both of basic scientific studies of naturally occurring invasion events and of applied investigations on the use of wolbachia as a vehicle to drive desired genotypes into insect populations (" ... | 2010 | 20601501 |
| female mate preferences in drosophila simulans: evolution and costs. | female mate preference is central to sexual selection, and all indirect benefit models require that there is genetic variation in female preference. this has rarely been tested however, with relatively few studies documenting heritable variation in female preference and even fewer that have directly selected on mate preference to unequivocally show that it can evolve. additionally, costs of mate preference are poorly understood even though these have implications for preference evolution. we sel ... | 2010 | 20546089 |
| thermal sensitivity of mitochondrial metabolism in two distinct mitotypes of drosophila simulans: evaluation of mitochondrial plasticity. | the overall aim of this study was to (1) evaluate the adaptive value of mitochondrial dna by comparing mitochondrial performance in populations possessing different haplotypes and distribution, and to (2) evaluate the sensitivity of different enzymes of the electron transport system (ets) during temperature-induced changes. we measured the impact of temperature of mitochondrial respiration and several key enzymes of mitochondrial metabolism in two mitotypes (siii and siiii) of drosophila simulan ... | 2010 | 20435817 |
| r2 retrotransposons encode a self-cleaving ribozyme for processing from an rrna cotranscript. | the non-long terminal repeat (non-ltr) retrotransposon r2 is inserted into the 28s rrna genes of many animals. expression of the element appears to be by cotranscription with the rrna gene unit. we show here that processing of the rrna cotranscript at the 5' end of the r2 element in drosophila simulans is rapid and utilizes an unexpected mechanism. using rna synthesized in vitro, the 5' untranslated region of r2 was shown capable of rapid and efficient self-cleavage of the 28s-r2 cotranscript. t ... | 2010 | 20421411 |
| recognition and detoxification of the insecticide ddt by drosophila melanogaster glutathione s-transferase d1. | gstd1 is one of several insect glutathione s-transferases capable of metabolizing the insecticide ddt. here we use crystallography and nmr to elucidate the binding of ddt and glutathione to gstd1. the crystal structure of drosophila melanogaster gstd1 has been determined to 1.1 a resolution, which reveals that the enzyme adopts the canonical gst fold but with a partially occluded active site caused by the packing of a c-terminal helix against one wall of the binding site for substrates. this hel ... | 2010 | 20417639 |
| hosimary: a new hat transposon group involved in horizontal transfer. | a pcr screening approach was used to search for sequences homologous to a previously described hat transposon found in drosophila simulans and drosophila sechellia, named here as hosimary. in this study, 52 drosophilidae species were analyzed and these sequences seem to be restricted to some species of the melanogaster group and zaprionus indianus. these species present variable number of copies and most of those appear to be putatively encoding. the high hosimary sequences similarity among diff ... | 2010 | 20339871 |
| monitoring long-term evolutionary changes following wolbachia introduction into a novel host: the wolbachia popcorn infection in drosophila simulans. | wolbachia may act as a biological control agent for pest management; in particular, the wolbachia variant wmelpop (popcorn) shortens host longevity and may be useful for dengue suppression. however, long-term changes in the host and wolbachia genomes can alter wolbachia spread and/or host effects that suppress disease. here, we investigate the phenotypic effects of wmelpop in a non-native host, drosophila simulans, following artificial transinfection approximately 200 generations ago. long-term ... | 2010 | 20219740 |
| transgenic drosophila simulans strains prove the identity of the speciation gene lethal hybrid rescue. | speciation genes are responsible for genetic incompatibilities in hybrids of incipient species and therefore participate in reproductive isolation leading to complete speciation. hybrid males between drosophila melanogaster females and d. simulans males die at late larval or prepupal stages due to a failure in chromosome condensation during mitosis. however a mutant male of d. simulans, named lethal hybrid rescue (lhr), produces viable hybrid males when crossed to females of d. melanogaster. rec ... | 2009 | 20154422 |
| translocation of y-linked genes to the dot chromosome in drosophila pseudoobscura. | one of the most striking cases of sex chromosome reorganization in drosophila occurred in the lineage ancestral to drosophila pseudoobscura, where there was a translocation of y-linked genes to an autosome. these genes went from being present only in males, never recombining, and having an effective population size of 0.5n to a state of autosomal linkage, where they are passed through both sexes, may recombine, and their effective population size has quadrupled. these genes appear to be function ... | 2010 | 20147437 |
| incorporating sequence quality data into alignment improves dna read mapping. | new dna sequencing technologies have achieved breakthroughs in throughput, at the expense of higher error rates. the primary way of interpreting biological sequences is via alignment, but standard alignment methods assume the sequences are accurate. here, we describe how to incorporate the per-base error probabilities reported by sequencers into alignment. unlike existing tools for dna read mapping, our method models both sequencer errors and real sequence differences. this approach consistently ... | 2010 | 20110255 |
| altered heterochromatin binding by a hybrid sterility protein in drosophila sibling species. | hybrid sterility of the heterogametic sex is one of the first postzygotic reproductive barriers to evolve during speciation, yet the molecular basis of hybrid sterility is poorly understood. we show that the hybrid male sterility gene odysseus-site homeobox (odsh) encodes a protein that localizes to evolutionarily dynamic loci within heterochromatin and leads to their decondensation. in drosophila mauritiana x drosophila simulans male hybrids, odsh from d. mauritiana (odshmau) acts as a steriliz ... | 2009 | 19933102 |
| variation in antiviral protection mediated by different wolbachia strains in drosophila simulans. | drosophila c virus (dcv) is a natural pathogen of drosophila and a useful model for studying antiviral defences. the drosophila host is also commonly infected with the widespread endosymbiotic bacteria wolbachia pipientis. when dcv coinfects wolbachia-infected d. melanogaster, virus particles accumulate more slowly and virus induced mortality is substantially delayed. considering that wolbachia is estimated to infect up to two-thirds of all insect species, the observed protective effects of wolb ... | 2009 | 19911047 |
| recurrent selection on the winters sex-ratio genes in drosophila simulans. | selfish genes, such as meiotic drive elements, propagate themselves through a population without increasing the fitness of host organisms. x-linked (or y-linked) meiotic drive elements reduce the transmission of the y (x) chromosome and skew progeny and population sex ratios, leading to intense conflict among genomic compartments. drosophila simulans is unusual in having a least three distinct systems of x chromosome meiotic drive. here, we characterize naturally occurring genetic variation at t ... | 2010 | 19897749 |
| species-specific heterochromatin prevents mitotic chromosome segregation to cause hybrid lethality in drosophila. | postzygotic reproductive barriers such as sterility and lethality of hybrids are important for establishing and maintaining reproductive isolation between species. identifying the causal loci and discerning how they interfere with the development of hybrids is essential for understanding how hybrid incompatibilities (his) evolve, but little is known about the mechanisms of how hi genes cause hybrid dysfunctions. a previously discovered drosophila melanogaster locus called zhr causes lethality in ... | 2009 | 19859525 |
| wolbachia interferes with ferritin expression and iron metabolism in insects. | wolbachia is an intracellular bacterium generally described as being a facultative reproductive parasite. however, wolbachia is necessary for oogenesis completion in the wasp asobara tabida. this dependence has evolved recently as a result of interference with apoptosis during oogenesis. through comparative transcriptomics between symbiotic and aposymbiotic individuals, we observed a differential expression of ferritin, which forms a complex involved in iron storage. iron is an essential element ... | 2009 | 19851452 |
| drosophila melanogaster males respond differently at the behavioural and genome-wide levels to drosophila melanogaster and drosophila simulans females. | drosophila melanogaster are found in sympatry with drosophila simulans, and matings between the species produce nonfertile hybrid offspring at low frequency. evolutionary theory predicts that females choose mates, so males should alter their behaviour in response to female cues. we show that d. melanogaster males quickly decrease courtship towards d. simulans females. courtship levels are reduced within 5 min of exposure to a heterospecific female, and overall courtship is significantly lower th ... | 2009 | 19765174 |
| allele-specific expression assays using solexa. | allele-specific expression (ase) assays can be used to identify cis, trans, and cis-by-trans regulatory variation. understanding the source of expression variation has important implications for disease susceptibility, phenotypic diversity, and adaptation. while ase is commonly measured via relative fluorescence at a snp, next generation sequencing provides an opportunity to measure ase in an accurate and high-throughput manner using read counts. | 2009 | 19740431 |
| effect of intracellular wolbachia on interspecific crosses between drosophila melanogaster and drosophila simulans. | wolbachia are bacteria that live inside the cells of a large number of invertebrate hosts and are transmitted from infected females to their offspring. their presence is associated with cytoplasmic incompatibility in several species of drosophila. cytoplasmic incompatibility results when the sperm of infected males fertilize eggs of uninfected females, causing more or less intense embryonic mortality (unidirectional incompatibility). this phenomenon also appears in crosses between populations in ... | 2009 | 19731208 |
| identification of quantitative trait loci function through analysis of multiple cuticular hydrocarbons differing between drosophila simulans and drosophila sechellia females. | the genetics of sexual isolation, behavioral differences between species that prevent mating, is understood poorly. pheromonal differences between species can influence sexual isolation in many animals and in some cases a single locus can cause large functional changes in pheromonal mating signals. drosophila cuticular hydrocarbons (chcs) can function as pheromones and consequently affect mate recognition. in a previous study of the two major chcs in females that affect mating discrimination bet ... | 2009 | 19654611 |
| high genetic differentiation between an african and a non-african strain of drosophila simulans revealed by segregation distortion and reduced crossover frequency. | drosophila simulans strains originating from madagascar and nearby islands in the indian ocean often differ from those elsewhere in the number of sex comb teeth and the degree of morphological anomaly in hybrids with d. melanogaster. here, we report a strong segregation distortion in the f1 intercross between two d. simulans strains originating from madagascar and the us, possibly at both the gametic and zygotic levels. strong bias against alleles of the madagascar strain was observed for all te ... | 2009 | 19590966 |
| molecular signature of epistatic selection: interrogating genetic interactions in the sex-ratio meiotic drive of drosophila simulans. | fine scale analyses of signatures of selection allow assessing quantitative aspects of a species' evolutionary genetic history, such as the strength of selection on genes. when several selected loci lie in the same genomic region, their epistatic interactions may also be investigated. here, we study how the neutral polymorphism pattern was shaped by two close recombining loci that cause 'sex-ratio' meiotic drive in drosophila simulans, as an example of strong selection with potentially strong ep ... | 2009 | 19589187 |
| evolution of postmating reproductive isolation: measuring the fitness effects of chromosomal regions containing hybrid male sterility factors. | at least six regions of the x chromosome can cause male sterility when introgressed from drosophila mauritiana into drosophila simulans. in this article, we present the results of the other fitness effects caused by two x-linked regions that contain hybrid male sterility factors. in both regions, females that are heterozygous for an introgression with such a sterility factor produce substantially-fewer offspring than females heterozygous for an introgression that lacks the sterility factor. thus ... | 1993 | 19425976 |
| the mosaic genome structure of the wolbachia wri strain infecting drosophila simulans. | the obligate intracellular bacterium wolbachia pipientis infects around 20% of all insect species. it is maternally inherited and induces reproductive alterations of insect populations by male killing, feminization, parthenogenesis, or cytoplasmic incompatibility. here, we present the 1,445,873-bp genome of w. pipientis strain wri that induces very strong cytoplasmic incompatibility in its natural host drosophila simulans. a comparison with the previously sequenced genome of w. pipientis strain ... | 2009 | 19307581 |
| the pattern of r2 retrotransposon activity in natural populations of drosophila simulans reflects the dynamic nature of the rdna locus. | the pattern and frequency of insertions that enable transposable elements to remain active in a population are poorly understood. the retrotransposable element r2 exclusively inserts into the 28s rrna genes where it establishes long-term, stable relationships with its animal hosts. previous studies with laboratory stocks of drosophila simulans have suggested that control over r2 retrotransposition resides within the rdna loci. in this report, we sampled 180 rdna loci of animals collected from tw ... | 2009 | 19229317 |
| sperm dumping as a defense against meiotic drive. | sperm from drosophila simulans that carry a sex-ratio distorter is preferentially lost from females' sperm-storage organs. this suggests that sperm dumping is a major factor affecting sperm competition in this species, and may have evolved in response to sex-ratio distorters. | 2009 | 19216726 |
| evolution of the drosophila nuclear pore complex results in multiple hybrid incompatibilities. | speciation often involves the evolution of incompatible gene interactions that cause sterility or lethality in hybrids between populations. these so-called hybrid incompatibilities occur between two or more functionally divergent loci. we show that the nucleoporin 160kda (nup160) gene of the fruitfly drosophila simulans is incompatible with one or more factors on the d. melanogaster x chromosome, causing hybrid lethality. nup160 encodes a nuclear pore complex protein and shows evidence of adapti ... | 2009 | 19197064 |
| genomic environment influences the dynamics of the tirant ltr retrotransposon in drosophila. | combining genome sequence analysis and functional analysis, we show that some full-length copies of tirant are present in heterochromatic regions in drosophila simulans and that when tested in vitro, these copies have a functional promoter. however, when inserted in heterochromatic regions, tirant copies are inactive in vivo, and only transcription of euchromatic copies can be detected. thus, our data indicate that the localization of the element is a hallmark of its activity in vivo and raise t ... | 2009 | 19141532 |
| female-driven mechanisms, ejaculate size and quality contribute to the lower fertility of sex-ratio distorter males in drosophila simulans. | sex-ratio meiotic drive refers to the preferential transmission of the x chromosome by xy males. the loss of y-bearing sperm is caused by an x-linked distorter and results in female-biased progeny. the fertility of sex-ratio (sr) males expressing the distorter is usually strongly reduced compared to wild-type males, especially when they are in competition. the aim of this study was to identify the post-copulatory mechanisms that lower the fertility of sr males in drosophila simulans. parameters ... | 2008 | 19055718 |
| molecular population genetics and evolution of drosophila meiosis genes. | while many functional elements of the meiotic process are well characterized in model organisms, the genetic basis of most of the natural phenotypic variation observed in meiotic pathways has not been determined. to begin to address this issue, we characterized patterns of polymorphism and divergence in the protein-coding regions of 33 genes across 31 lines of drosophila melanogaster and 6 lines of drosophila simulans. we sequenced genes known to be involved in chromosome segregation, recombinat ... | 2009 | 18984573 |
| investigating latitudinal clines for life history and stress resistance traits in drosophila simulans from eastern australia. | latitudinal clines have been demonstrated for many quantitative traits in drosophila and are assumed to be due to climatic selection. however, clinal studies are often performed in species of drosophila that contain common cosmopolitan inversion polymorphisms that also show clinal patterns. these inversion polymorphisms may be responsible for much of the observed clinal variation. here, we consider latitudinal clines for quantitative traits in drosophila simulans from eastern australia. drosophi ... | 2008 | 18811666 |
| behavior of wolbachia endosymbionts from drosophila simulans in drosophila serrata, a novel host. | many species harbor the incompatibility-inducing microbe wolbachia, a maternally inherited endoparasite that causes reduced egg hatch in crosses between infected males and uninfected females. infected females are immune to this effect, which gives them a relative fitness advantage that results in the spread of the infection. the strength of incompatibility, fitness deficits associated with the infection, and transmission rate from mother to offspring largely determine the rate and extent of spre ... | 1997 | 18811258 |
| recurrent positive selection of the drosophila hybrid incompatibility gene hmr. | lethality in hybrids between drosophila melanogaster and its sibling species drosophila simulans is caused in part by the interaction of the genes hybrid male rescue (hmr) and lethal hybrid rescue (lhr). hmr and lhr have diverged under positive selection in the hybridizing species. here we test whether positive selection of hmr is confined only to d. melanogaster and d. simulans. we find that hmr has continued to diverge under recurrent positive selection between the sibling species d. simulans ... | 2008 | 18755760 |
| gene expression disruptions of organism versus organ in drosophila species hybrids. | hybrid dysfunctions, such as sterility, may result in part from disruptions in the regulation of gene expression. studies of hybrids within the drosophila simulans clade have reported genes expressed above or below the expression observed in their parent species, and such misexpression is associated with male sterility in multigenerational backcross hybrids. however, these studies often examined whole bodies rather than testes or had limited replication using less-sensitive but global techniques ... | 2008 | 18714377 |
| starvation resistance is positively correlated with body lipid proportion in five wild caught drosophila simulans populations. | stress resistance traits in drosophila often show clinal variation, suggesting that selection affects resistance traits either directly or indirectly. one of the most common causes of stress for animals is the shortage or suboptimal quality of food, and individuals within many species must survive periods of starvation or exposure to nutritionally imbalanced diets. this study determines the relationship between starvation resistance, body lipid content, and lifespan in five recently collected dr ... | 2008 | 18706419 |
| genomic analysis of the relationship between gene expression variation and dna polymorphism in drosophila simulans. | understanding how dna sequence polymorphism relates to variation in gene expression is essential to connecting genotypic differences with phenotypic differences among individuals. addressing this question requires linking population genomic data with gene expression variation. | 2008 | 18700012 |
| quantifying the stationarity and time reversibility of the nucleotide substitution process. | markov models describing the evolution of the nucleotide substitution process, widely used in phylogeny reconstruction, usually assume the hypotheses of stationarity and time reversibility. although these models give meaningful results when applied to biological data, it is not clear if the 2 assumptions mentioned above hold and, if not, how much sequence evolution processes deviate from them. to this aim, we introduce 2 sets of indices that can be calculated from the nucleotide distribution and ... | 2008 | 18682605 |
| epigenetic regulation of retrotransposons within the nucleolus of drosophila. | r2 retrotransposable elements exclusively insert into a conserved region of the tandemly organized 28s rrna genes. despite inactivating a subset of these genes, r2 elements have persisted in the ribosomal dna (rdna) loci of insects for hundreds of millions of years. controlling r2 proliferation was addressed in this study using lines of drosophila simulans previously shown to have either active or inactive r2 retrotransposition. lines with active retrotransposition were shown to have high r2 tra ... | 2008 | 18678644 |
| validation of manometric microrespirometers for measuring oxygen consumption in small arthropods. | scientists have used numerous techniques to measure organismal metabolic rate, including assays of oxygen (o2) consumption and carbon dioxide (co2) production. relatively few studies have directly compared estimates of metabolic rate on the same groups of animals as determined by different assay methods. this study directly compared measures of the metabolic rate of three lines of drosophila simulans as determined either from direct measures of co2 production using infrared gas analysis (irga), ... | 2008 | 18606168 |
| estimation of isolation times of the island species in the drosophila simulans complex from multilocus dna sequence data. | the drosophila simulans species complex continues to serve as an important model system for the study of new species formation. the complex is comprised of the cosmopolitan species, d. simulans, and two island endemics, d. mauritiana and d. sechellia. a substantial amount of effort has gone into reconstructing the natural history of the complex, in part to infer the context in which functional divergence among the species has arisen. in this regard, a key parameter to be estimated is the initial ... | 2008 | 18560591 |
| positive and negative selection on noncoding dna in drosophila simulans. | there is now a wealth of evidence that some of the most important regions of the genome are found outside those that encode proteins, and noncoding regions of the genome have been shown to be subject to substantial levels of selective constraint, particularly in drosophila. recent work has suggested that these regions may also have been subject to the action of positive selection, with large fractions of noncoding divergence having been driven to fixation by adaptive evolution. however, this wor ... | 2008 | 18515263 |
| non-neutral processes drive the nucleotide composition of non-coding sequences in drosophila. | the nature of the forces affecting base composition is a key question in genome evolution. there is uncertainty as to whether differences in the gc contents of non-coding sequences reflect differences in mutational bias, or in the intensity of selection or biased gene conversion. we have used a polymorphism dataset for non-coding sequences on the x chromosome of drosophila simulans to examine this question. the proportion of gc-->at versus at-->gc polymorphic mutations in a locus is correlated w ... | 2008 | 18505714 |
| genetic and functional characterization of the type iv secretion system in wolbachia. | a type iv secretion system (t4ss) is used by many symbiotic and pathogenic intracellular bacteria for the successful infection of and survival, proliferation, and persistence within hosts. in this study, the presence and function of the t4ss in wolbachia strains were investigated by a combination of genetic screening and immunofluorescence microscopy. two operons of virb-vird4 loci were found in the genome of wolbachia pipientis strain watab3, from the hymenoptera asobara tabida, and strain wri, ... | 2008 | 18502862 |
| the mariner transposable element in natural populations of drosophila simulans. | in cosmopolitan species, geographical variations in copy number and/or level of transposition activity have been observed for several transposable elements (tes). environment, history and population structure can contribute to such variation in ways that are difficult to tease apart. for the mariner element, previous studies of the geographic variation of its somatic activity in natural populations of drosophila simulans have shown contradictory results (latitudinal clines of divergent orientati ... | 2008 | 18461087 |
| wolbachia infection alters olfactory-cued locomotion in drosophila spp. | wolbachia pipientis is an endosymbiotic bacterium present in diverse insect species. although it is well studied for its dramatic effects on host reproductive biology, little is known about its effects on other aspects of host biology, despite its presence in a wide array of host tissues. this study examined the effects of three wolbachia strains on two different drosophila species, using a laboratory performance assay for insect locomotion in response to olfactory cues. the results demonstrate ... | 2008 | 18456851 |
| the acylphosphatase (acyp) alleles associate with male hybrid sterility in drosophila. | hybrid defects are believed to result from genetic incompatibilities between genes that have evolved in separate parental lineages. these genetic dysfunctions on the hybrid genomic background, also known as dobzhansky-muller incompatibilities, can be an incipient signature of speciation, and as such - a subject of active research. here we present evidence that acyp locus (cg16870) that encodes acylphosphatase, a small enzyme that catalyzes the hydrolysis of acylphosphates and participates in ion ... | 2008 | 18440166 |
| multiple rescue factors within a wolbachia strain. | wolbachia-induced cytoplasmic incompatibility (ci) is expressed when infected males are crossed with either uninfected females or females infected with wolbachia of different ci specificity. in diploid insects, ci results in embryonic mortality, apparently due to the the loss of the paternal set of chromosomes, usually during the first mitotic division. the molecular basis of ci has not been determined yet; however, several lines of evidence suggest that wolbachia exhibits two distinct sex-depen ... | 2008 | 18430940 |
| recurrent tandem gene duplication gave rise to functionally divergent genes in drosophila. | tandem gene duplication is one of the major gene duplication mechanisms in eukaryotes, as illustrated by the prevalence of gene family clusters. tandem duplicated paralogs usually share the same regulatory element, and as a consequence, they are likely to perform similar biological functions. here, we provide an example of a newly evolved tandem duplicate acquiring novel functions, which were driven by positive selection. cg32708, cg32706, and cg6999 are 3 clustered genes residing in the x chrom ... | 2008 | 18408233 |
| a candidate complex approach to study functional mitochondrial dna changes: sequence variation and quaternary structure modeling of drosophila simulans cytochrome c oxidase. | a problem with studying evolutionary dynamics of mitochondrial (mt) dna is that classical population genetic techniques cannot identify selected substitutions because of genetic hitchhiking. we circumvented this problem by employing a candidate complex approach to study sequence variation in cytochrome c oxidase (cox) genes within and among three distinct drosophila simulans mtdna haplogroups. first, we determined sequence variation in complete coding regions for all cox mtdna and nuclear loci a ... | 2008 | 18320260 |
| an intron loss of dfak gene in species of the drosophila melanogaster subgroup and phylogenetic analysis. | drosophila focal adhesion kinase (dfak) gene is a single-copy nuclear gene. previous study revealed that drosophila melanogaster and drosophila simulans had lost an intron precisely within the tyrosine kinase (tyk) domain of this gene. however, this did not happen in several other drosophila species, including drosophila elegans, drosophila ficusphila, drosophila biarmipes, drosophila jambulina, drosophila prostipennis, drosophila takahashii, and drosophila pseudoobscura. in the current study, h ... | 2009 | 18310070 |
| drosophila simulans lethal hybrid rescue mutation (lhr) rescues inviable hybrids by restoring x chromosomal dosage compensation and causes fluctuating asymmetry of development. | the drosophila simulans lhr rescues lethal hybrids from the cross of d. melanogaster and d. simulans. we describe here, the phenotypes of lhr dependent rescue hybrids and demonstrate the effects of lhr on functional morphology of the salivary chromosomes in the hybrids. our results reveal that the phenotypes of the 'lhr dependent rescued' hybrids were largely dependent on the genetic background and the dominance in species and hybrids, and not on lhr. cytological examination reveal that while th ... | 2007 | 18305340 |
| evolution of gene expression in the drosophila olfactory system. | host plant shifts by phytophagous insects play a key role in insect evolution and plant ecology. such shifts often involve major behavioral changes as the insects must acquire an attraction and/or lose the repulsion to the new host plant's odor and taste. the evolution of chemotactic behavior may be due, in part, to gene expression changes in the peripheral sensory system. to test this hypothesis, we compared gene expression in the olfactory organs of drosophila sechellia, a narrow ecological sp ... | 2008 | 18296696 |
| a new test for selection applied to codon usage in drosophila simulans and d. mauritiana. | in many organisms, synonymous codon usage is biased by a history of natural selection. however, codon bias, itself, does not indicate that selection is ongoing; it may be a vestige of past selection. simple statistical tests have been devised to infer ongoing selection on codon usage by comparing the derived state frequency spectra at polymorphic sites segregating either derived preferred codons or derived unpreferred codons; if selection is effective, the frequency of derived states should be h ... | 2008 | 18288436 |
| divergence times in caenorhabditis and drosophila inferred from direct estimates of the neutral mutation rate. | accurate inference of the dates of common ancestry among species forms a central problem in understanding the evolutionary history of organisms. molecular estimates of divergence time rely on the molecular evolutionary prediction that neutral mutations and substitutions occur at the same constant rate in genomes of related species. this underlies the notion of a molecular clock. most implementations of this idea depend on paleontological calibration to infer dates of common ancestry, but taxa wi ... | 2008 | 18234705 |
| evolution of a desaturase involved in female pheromonal cuticular hydrocarbon biosynthesis and courtship behavior in drosophila. | drosophila species exhibit polymorphism in female pheromonal cuticular hydrocarbons, with 7-monoenes produced in drosophila simulans and 7,11-dienes in most populations of drosophila melanogaster (5,9-dienes in several african populations). a female-biased desaturase, desatf, expressed only in d. melanogaster is involved in the synthesis of 7,11-dienes. we investigated the role of desatf in 5,9-diene flies. we constructed a 5,9-diene strain knock-down for desatf and showed that desatf is involve ... | 2008 | 18207084 |
| the impact of shared ancestral variation on hybrid male lethality--a 16 codon indel in the drosophila simulans lhr gene. | the lethal hybrid rescue (lhr) gene causes hybrid male lethality in crosses between drosophila simulans and d. melanogaster. lhr(2) is a d. simulans allele, which rescues hybrid males. it has been recently proposed that a 16 codon insertion, which distinguishes the d. melanogaster and the canonical d. simulans allele, and is lacking in lhr(2), may be responsible for the functional divergence of d. melanogaster and d. simulans lhr alleles. here, we show that the lhr(2) allele lacking the insertio ... | 2008 | 18194231 |
| the expression of alleles at the cubitus interrupts locus in hybrids between drosophila melanogaster and drosophila simulans. | 1949 | 18131555 | |
| tetracycline treatment influences mitochondrial metabolism and mtdna density two generations after treatment in drosophila. | tetracycline is commonly used to clear wolbachia from infected insects. studies then compare specific biochemical and/or life-history traits between infected and uninfected individuals with the same genetic background. we investigated the potential for tetracycline to influence mitochondrial efficiency and mitochondrial (mt)dna density two generations after treatment in drosophila simulans. we observed that antibiotic treatment resulted in a decline in inorganic phosphate incorporated into atp p ... | 2007 | 18093008 |
| the structure of the 18s rrna, a molecule that might be evolutionarily related to some receptors of innate immunity. | comparisons between the sequences of insect and vertebrate 18s rrnas and the sequences of mammalian formyl peptide and some vertebrate chemokine receptor mrnas demonstrated non-random structural similarities between these two groups of rnas. it has been proposed that sections of the more ancient and conserved rrna genes could have participated in the building of these more recent genes involved in immune responses. here we analyze the sequence architecture of the 18s rrna in insects (drosophila ... | 2007 | 18075861 |
| genomewide spatial correspondence between nonsynonymous divergence and neutral polymorphism reveals extensive adaptation in drosophila. | the effect of recurrent selective sweeps is a spatially heterogeneous reduction in neutral polymorphism throughout the genome. the pattern of reduction depends on the selective advantage and recurrence rate of the sweeps. because many adaptive substitutions responsible for these sweeps also contribute to nonsynonymous divergence, the spatial distribution of nonsynonymous divergence also reflects the distribution of adaptive substitutions. thus, the spatial correspondence between neutral polymorp ... | 2007 | 18073425 |
| selective sweeps in a 2-locus model for sex-ratio meiotic drive in drosophila simulans. | a way to identify loci subject to positive selection is to detect the signature of selective sweeps in given chromosomal regions. it is revealed by the departure of dna polymorphism patterns from the neutral equilibrium predicted by coalescent theory. we surveyed dna sequence variation in a region formerly identified as causing "sex-ratio" meiotic drive in drosophila simulans. we found evidence that this system evolved by positive selection at 2 neighboring loci, which thus appear to be required ... | 2008 | 18071199 |
| do wolbachia-associated incompatibilities promote polyandry? | the genetic incompatibility avoidance hypothesis as an explanation for the polyandrous mating strategies (mating with more than one male) of females of many species has received significant attention in recent years. it has received support from both empirical studies and a meta-analysis, which concludes that polyandrous females enjoy increased reproductive success through improved offspring viability relative to monandrous females. in this study we investigate whether polyandrous female drosoph ... | 2008 | 18067571 |
| rapid r2 retrotransposition leads to the loss of previously inserted copies via large deletions of the rdna locus. | r2 non-long terminal repeat retrotransposable elements insert specifically into the 28s rrna genes of a wide range of animals. these elements maintain long-term stable relationships with the host genome. by scoring the variation present at the 5' ends of individual r2 copies, lines of drosophila simulans have been identified with high rates of r2 retrotransposition. comparing the r2 elements present in the parents with that of their progeny after 1 or 30 generations in this report revealed that ... | 2008 | 18003600 |
| population genomics: whole-genome analysis of polymorphism and divergence in drosophila simulans. | the population genetic perspective is that the processes shaping genomic variation can be revealed only through simultaneous investigation of sequence polymorphism and divergence within and between closely related species. here we present a population genetic analysis of drosophila simulans based on whole-genome shotgun sequencing of multiple inbred lines and comparison of the resulting data to genome assemblies of the closely related species, d. melanogaster and d. yakuba. we discovered previou ... | 2007 | 17988176 |
| a sex-ratio meiotic drive system in drosophila simulans. ii: an x-linked distorter. | the evolution of heteromorphic sex chromosomes creates a genetic condition favoring the invasion of sex-ratio meiotic drive elements, resulting in the biased transmission of one sex chromosome over the other, in violation of mendel's first law. the molecular mechanisms of sex-ratio meiotic drive may therefore help us to understand the evolutionary forces shaping the meiotic behavior of the sex chromosomes. here we characterize a sex-ratio distorter on the x chromosome (dox) in drosophila simulan ... | 2007 | 17988173 |
| a sex-ratio meiotic drive system in drosophila simulans. i: an autosomal suppressor. | sex ratio distortion (sex-ratio for short) has been reported in numerous species such as drosophila, where distortion can readily be detected in experimental crosses, but the molecular mechanisms remain elusive. here we characterize an autosomal sex-ratio suppressor from d. simulans that we designate as not much yang (nmy, polytene chromosome position 87f3). nmy suppresses an x-linked sex-ratio distorter, contains a pair of near-perfect inverted repeats of 345 bp, and evidently originated throug ... | 2007 | 17988172 |
| rampant adaptive evolution in regions of proteins with unknown function in drosophila simulans. | adaptive protein evolution is pervasive in drosophila. genomic studies, thus far, have analyzed each protein as a single entity. however, the targets of adaptive events may be localized to particular parts of proteins, such as protein domains or regions involved in protein folding. we compared the population genetic mechanisms driving sequence polymorphism and divergence in defined protein domains and non-domain regions. interestingly, we find that non-domain regions of proteins are more frequen ... | 2007 | 17971876 |
| adaptive gene expression divergence inferred from population genomics. | detailed studies of individual genes have shown that gene expression divergence often results from adaptive evolution of regulatory sequence. genome-wide analyses, however, have yet to unite patterns of gene expression with polymorphism and divergence to infer population genetic mechanisms underlying expression evolution. here, we combined genomic expression data--analyzed in a phylogenetic context--with whole genome light-shotgun sequence data from six drosophila simulans lines and reference se ... | 2007 | 17967066 |
| comparative analysis of mitochondrial genotype and aging. | a common feature across all animals, including humans, is that mitochondrial bioenergetics is linked to oxidative stress, but the nature of these relationships with survival is yet to be properly defined. in this study we included 12 drosophila simulans isofemale lines: four of each distinct mtdna haplogroup (sii, -ii, and -iii). first, we investigated sequence variation in six mtdna and 13 nuclear encoded genes (nine nuclear-encoded subunits, and the four known isoforms, of complex iv of the el ... | 2007 | 17934050 |
| working harder to stay alive: metabolic rate increases with age in drosophila simulans but does not correlate with life span. | the hypothesis that metabolic rate is inversely correlated with life span has long been debated. another area of controversy has been the relationship between metabolic rate and aging. in most molecular studies key aspects of cellular metabolism have been shown to decline with age. less attention has been focused on metabolic rate as an organism ages. we studied the survival of three drosophila simulans fly lines and measured whole organism metabolic rate, mitochondrial dna copy number and walki ... | 2007 | 17915248 |
| adaptive protein evolution of x-linked and autosomal genes in drosophila: implications for faster-x hypotheses. | patterns of sex chromosome and autosome evolution can be used to elucidate the underlying genetic basis of adaptative change. evolutionary theory predicts that x-linked genes will adapt more rapidly than autosomes if adaptation is limited by the availability of beneficial mutations and if such mutations are recessive. in drosophila, rates of molecular divergence between species appear to be equivalent between autosomes and the x chromosome. however, molecular divergence contrasts are difficult t ... | 2007 | 17884828 |
| species-specific positive selection of the male-specific lethal complex that participates in dosage compensation in drosophila. | in many taxa, males and females have unequal ratios of sex chromosomes to autosomes, which has resulted in the invention of diverse mechanisms to equilibrate gene expression between the sexes (dosage compensation). failure to compensate for sex chromosome dosage results in male lethality in drosophila. in drosophila, a male-specific lethal (msl) complex of proteins and noncoding rnas binds to hundreds of sites on the single male x chromosome and up-regulates gene expression. here we use populati ... | 2007 | 17878295 |
| intersexes in drosophila simulans. | 1920 | 17773838 | |
| sex differences in survival and mitochondrial bioenergetics during aging in drosophila. | the goal of this study is to test the role of mitochondria and of mitochondrial metabolism in determining the processes that influence aging of female and male drosophila. we observe that drosophila simulans females tended to have shorter lifespan, higher levels of hydrogen peroxide production and significantly lower levels of catalase but not superoxide dismutase compared to males. in contrast, mammalian females tend to be longer lived, have lower rates of reactive oxygen species production and ... | 2007 | 17725690 |
| effects of wolbachia on sperm maturation and architecture in drosophila simulans riverside. | wolbachia is an intracellular obligate symbiont, that is relatively common in insects and also found in some nematodes. cytoplasmic incompatibility (ci) is the most commonly expressed form, of several sex altering phenotypes caused by this rickettsial-like bacterium. ci is induced when infected males mate with uninfected females, and is likely the result of bacterial-induced modification of sperm grown in a wolbachia-infected environment. several studies have explored the dynamics of wolbachia b ... | 2007 | 17693061 |