Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| cytoplasmic incompatibility in drosophila simulans: evolving complexity. | 1996 | 21237786 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| empirical evidence for son-killing x chromosomes and the operation of sa-zygotic drive. | diploid organisms have two copies of all genes, but only one is carried by each haploid gamete and diploid offspring. this causes a fundamental genetic conflict over transmission rate between alternative alleles. single genes, or gene clusters, only rarely code for the complex phenotypes needed to give them a transmission advantage (drive phenotype). however, all genes on a male's x and y chromosomes co-segregate, allowing different sex-linked genes to code for different parts of the drive pheno ... | 2011 | 21858149 |
| adaptive evolution of a novel drosophila lectin induced by parasitic wasp attack. | drosophila melanogaster has long been used as a model for the molecular genetics of innate immunity. such work has uncovered several immune receptors that recognize bacterial and fungal pathogens by binding unique components of their cell walls and membranes. drosophila also act as hosts to metazoan pathogens such as parasitic wasps, which can infect a majority of individuals in natural populations, but many aspects of their immune responses against these more closely related pathogens are poorl ... | 2012 | 21873297 |
| a general method for calculating likelihoods under the coalescent process. | analysis of genomic data requires an efficient way to calculate likelihoods across very large numbers of loci. we describe a general method for finding the distribution of genealogies: we allow migration between demes, splitting of demes [as in the isolation-with-migration (im) model], and recombination between linked loci. these processes are described by a set of linear recursions for the generating function of branch lengths. under the infinite-sites model, the probability of any configuratio ... | 2011 | 21900266 |
| selection and constraint on regulatory elements in drosophila simulans. | we utilized available drosophila simulans molecular population genomic data to characterize sequence polymorphism in noncoding regulatory regions and their corresponding transcribed target genes or interacting transcription factors. we highlight two properties of regulatory evolution. first, we find that sequence divergence between d. melanogaster and d. simulans is greater at regulatory sites than expected from levels of intraspecific polymorphism, suggestive of positive selection. second, we c ... | 2011 | 21904868 |
| temporally variable selection on proteolysis-related reproductive tract proteins in drosophila. | in order to gain further insight into the processes underlying rapid reproductive protein evolution, we have conducted a population genetic survey of 44 reproductive tract-expressed proteases, protease inhibitors, and targets of proteolysis in drosophila melanogaster and drosophila simulans. our findings suggest that positive selection on this group of genes is temporally heterogeneous, with different patterns of selection inferred using tests sensitive at different time scales. such variation i ... | 2012 | 21940639 |
| next-generation mapping of complex traits with phenotype-based selection and introgression. | finding the genes underlying complex traits is difficult. we show that new sequencing technology combined with traditional genetic techniques can efficiently identify genetic regions underlying a complex and quantitative behavioral trait. as a proof of concept we used phenotype-based introgression to backcross loci that control innate food preference in drosophila simulans into the genomic background of d. sechellia, which expresses the opposite preference. we successfully mapped d. simulans int ... | 2011 | 21940681 |
| a comparison of frost expression among species and life stages of drosophila. | frost (fst) is a gene associated with cold exposure in drosophila melanogaster. we used real-time pcr to assess whether cold exposure induces expression of fst in 10 different life stages of d. melanogaster, and adults of seven other drosophila species. we exposed groups of individuals to 0 °c (2 h), followed by 1 h recovery (22 °c). frost was significantly upregulated in response to cold in eggs, third instar larvae, and 2- and 5-day-old male and female adults in d. melanogaster. life stages in ... | 2012 | 21955087 |
| retrotransposition of r2 elements in somatic nuclei during the early development of drosophila. | r2 retrotransposable elements exclusively insert in the 28s rrna genes of their host. their rna transcripts are produced by self-processing from a 28s r2 cotranscript. because full-length r2 transcripts are found in most tissues of r2-active animals, we tested whether new r2 insertions occurred in somatic tissues even though such events would be an evolutionary dead end. | 2011 | 21958913 |
| interspecific y chromosome introgressions disrupt testis-specific gene expression and male reproductive phenotypes in drosophila. | the drosophila y chromosome is a degenerated, heterochromatic chromosome with few functional genes. nonetheless, natural variation on the y chromosome in drosophila melanogaster has substantial trans-acting effects on the regulation of x-linked and autosomal genes. however, the contribution of y chromosome divergence to gene expression divergence between species is unknown. in this study, we constructed a series of y chromosome introgression lines, in which y chromosomes from either drosophila s ... | 2011 | 21969588 |
| the genomic response to courtship song stimulation in female drosophila melanogaster. | courtship behaviour involves a complex exchange of signals and responses. these are usually studied at the phenotypic level, and genetic or transcriptional responses to courtship are still poorly understood. here, we examine the gene-expression changes in drosophila melanogaster females in response to one of the key male courtship signals in mate recognition, song produced by male wing vibration. using long oligonucleotide microarrays, we identified several genes that responded differentially to ... | 2012 | 21976688 |
| wolbachia-mediated antibacterial protection and immune gene regulation in drosophila. | the outcome of microbial infection of insects is dependent not only on interactions between the host and pathogen, but also on the interactions between microbes that co-infect the host. recently the maternally inherited endosymbiotic bacteria wolbachia has been shown to protect insects from a range of microbial and eukaryotic pathogens. mosquitoes experimentally infected with wolbachia have upregulated immune responses and are protected from a number of pathogens including viruses, bacteria, pla ... | 2011 | 21980455 |
| widespread polymorphism in the positions of stop codons in drosophila melanogaster. | the mechanisms underlying evolutionary changes in protein length are poorly understood. protein domains are lost and gained between species and must have arisen first as within-species polymorphisms. here, we use drosophila melanogaster population genomic data combined with between species divergence information to understand the evolutionary forces that generate and maintain polymorphisms causing changes in protein length in d. melanogaster. specifically, we looked for protein length variations ... | 2012 | 22051795 |
| ephemeral association between gene cg5762 and hybrid male sterility in drosophila sibling species. | interspecies divergence in regulatory pathways may result in hybrid male sterility (hms) when dominance and epistatic interactions between alleles that are functional within one genome are disrupted in hybrid genomes. the identification of genes contributing to hms and other hybrid dysfunctions is essential for understanding the origin of new species (speciation). previously, we identified a panel of male-specific loci misexpressed in sterile male hybrids of drosophila simulans and d. mauritiana ... | 2011 | 22052252 |
| drosophila duplication hotspots are associated with late-replicating regions of the genome. | duplications play a significant role in both extremes of the phenotypic spectrum of newly arising mutations: they can have severe deleterious effects (e.g. duplications underlie a variety of diseases) but can also be highly advantageous. the phenotypic potential of newly arisen duplications has stimulated wide interest in both the mutational and selective processes shaping these variants in the genome. here we take advantage of the drosophila simulans-drosophila melanogaster genetic system to fu ... | 2011 | 22072977 |
| the bacteriophage woric is the active phage element in wri of drosophila simulans and represents a conserved class of wo phages. | the alphaproteobacterium wolbachia pipientis, the most common endosymbiont in eukaryotes, is found predominantly in insects including many drosophila species. although wolbachia is primarily vertically transmitted, analysis of its genome provides evidence for frequent horizontal transfer, extensive recombination and numerous mobile genetic elements. the genome sequence of wolbachia in drosophila simulans riverside (wri) is available along with the integrated bacteriophages, enabling a detailed e ... | 2011 | 22085419 |
| neural representations of courtship song in the drosophila brain. | acoustic communication in drosophilid flies is based on the production and perception of courtship songs, which facilitate mating. despite decades of research on courtship songs and behavior in drosophila, central auditory responses have remained uncharacterized. in this study, we report on intracellular recordings from central neurons that innervate the drosophila antennal mechanosensory and motor center (ammc), the first relay for auditory information in the fly brain. these neurons produce gr ... | 2012 | 22262877 |
| the genetics of cuticular hydrocarbon profiles in the fruit fly drosophila simulans. | female mate choice is one mechanism of sexual selection and, provided there is adequate genetic variation in the male traits that are the target of this selection, they will evolve via female choice. cuticular hydrocarbons (chcs) are important in drosophila mate choice, but relatively little is known about the underlying genetic architecture of chc profiles in drosophila simulans. here, we used gas chromatography-mass spectrometry to investigate patterns of genetic variation in the chc profiles ... | 2012 | 22268163 |
| tirant, a newly discovered active endogenous retrovirus in drosophila simulans. | endogenous retroviruses have the ability to become permanently integrated into the genomes of their host, and they are generally transmitted vertically from parent to progeny. with the exception of gypsy, few endogenous retroviruses have been identified in insects. in this study, we describe the tirant endogenous retrovirus in a subset of drosophila simulans natural populations. by focusing on the envelope gene, we show that the entire retroviral cycle (transcription, translation, and retrotrans ... | 2012 | 22278247 |
| functional evidence that a recently evolved drosophila sperm-specific gene boosts sperm competition. | in many species, both morphological and molecular traits related to sex and reproduction evolve faster in males than in females. ultimately, rapid male evolution relies on the acquisition of genetic variation associated with differential reproductive success. many newly evolved genes are associated with novel functions that might enhance male fitness. however, functional evidence of the adaptive role of recently originated genes in males is still lacking. the sperm dynein intermediate chain mult ... | 2012 | 22308475 |
| allelic imbalance in drosophila hybrid heads: exons, isoforms, and evolution. | unraveling how regulatory divergence contributes to species differences and adaptation requires identifying functional variants from among millions of genetic differences. analysis of allelic imbalance (ai) reveals functional genetic differences in cis regulation and has demonstrated differences in cis regulation within and between species. regulatory mechanisms are often highly conserved, yet differences between species in gene expression are extensive. what evolutionary forces explain widespre ... | 2012 | 22319150 |
| abundant genetic variability in drosophila simulans for hybrid female lethality in interspecific crosses to drosophila melanogaster. | intrinsic postzygotic reproductive isolation is thought to result from the substitution of multiple harmless or beneficial genetic differences between species that are incidentally deleterious when combined in species hybrids, causing hybrid sterility or inviability. genetic variability for hybrid sterility or inviability phenotypes is, however, rarely assessed in natural populations. here, we assess variation for drosophila simulans-encoded maternal factor(s) that cause lethality in d. simulans ... | 2012 | 22353244 |
| antagonistic responses to natural and sexual selection and the sex-specific evolution of cuticular hydrocarbons in drosophila simulans. | natural and sexual selection are classically thought to oppose one another, and although there is evidence for this, direct experimental demonstrations of this antagonism are largely lacking. here, we assessed the effects of sexual and natural selection on the evolution of cuticular hydrocarbons (chcs), a character subject to both modes of selection, in drosophila simulans. natural selection and sexual selection were manipulated in a fully factorial design, and after 27 generations of experiment ... | 2012 | 22380431 |
| sequence analysis of the segmental duplication responsible for paris sex-ratio drive in drosophila simulans. | sex-ratio distorters are x-linked selfish genetic elements that facilitate their own transmission by subverting mendelian segregation at the expense of the y chromosome. naturally occurring cases of sex-linked distorters have been reported in a variety of organisms, including several species of drosophila; they trigger genetic conflict over the sex ratio, which is an important evolutionary force. however, with a few exceptions, the causal loci are unknown. here, we molecularly characterize the s ... | 2011 | 22384350 |
| partitioning transcript variation in drosophila: abundance, isoforms, and alleles. | multilevel analysis of transcription is facilitated by a new array design that includes modules for assessment of differential expression, isoform usage, and allelic imbalance in drosophila. the ∼2.5 million feature chip incorporates a large number of controls, and it contains 18,769 3' expression probe sets and 61,919 exon probe sets with probe sequences from drosophila melanogaster and 60,118 snp probe sets focused on drosophila simulans. an experiment in d. simulans identified genes different ... | 2011 | 22384353 |
| high-throughput pcr assays to monitor wolbachia infection in the dengue mosquito (aedes aegypti) and drosophila simulans. | we have developed and validated two new fluorescence-based pcr assays to detect the wolbachia wmel strain in aedes aegypti and the wri and wau strains in drosophila simulans. the new assays are accurate, informative, and cost-efficient for large-scale wolbachia screening. | 2012 | 22522691 |
| genome sequencing reveals complex speciation in the drosophila simulans clade. | the three species of the drosophila simulans clade--the cosmopolitan species, d. simulans, and the two island endemic species, d. mauritiana and d. sechellia--are important models in speciation genetics, but some details of their phylogenetic and speciation history remain unresolved. the order and timing of speciation are disputed, and the existence, magnitude, and timing of gene flow among the three species remain unclear. here we report on the analysis of a whole-genome four-species sequence a ... | 2012 | 22534282 |
| a comparative analysis of the amounts and dynamics of transposable elements in natural populations of drosophila melanogaster and drosophila simulans. | genes are important in defining genetic variability, but they do not constitute the largest component of genomes, which in most organisms contain large amounts of various repeated sequences including transposable elements (tes), which have been shown to account for most of the genome size. tes contribute to genetic diversity by their mutational potential as a result of their ability to insert into genes or gene regulator regions, to promote chromosomal rearrangements, and to interfere with gene ... | 2012 | 22659421 |
| major role of positive selection in the evolution of conservative segments of drosophila proteins. | slow evolution of conservative segments of coding and non-coding dna is caused by the action of negative selection, which removes new mutations. however, the mode of selection that affects the few substitutions that do occur within such segments remains unclear. here, we show that the fraction of allele replacements that were driven by positive selection, and the strength of this selection, is the highest within the conservative segments of drosophila protein-coding genes. the mcdonald-kreitman ... | 2012 | 22673359 |
| fine-scale genetic analysis of species-specific female preference in drosophila simulans. | behavioural differences are thought to be the first components to contribute to species isolation, yet the precise genetic basis of behavioural isolation remains poorly understood. here, we used a combination of behaviour assays and genetic mapping to provide the first refined map locating candidate genes for interspecific female preference isolating drosophila simulans from d. melanogaster. first, we tested whether two genes identified as affecting d. melanogaster female intraspecific mate choi ... | 2012 | 22694106 |
| chemical cues influence pupation behavior of drosophila simulans and drosophila buzzatii in nature and in the laboratory. | in the wild, larvae of several species of drosophila develop in heterogeneous and rapidly changing environments sharing resources as food and space. in this scenario, sensory systems contribute to detect, localize and recognize congeners and heterospecifics, and provide information about the availability of food and chemical features of environments where animals live. we investigated the behavior of d. simulans and d. buzzatii larvae to chemicals emitted by conspecific and heterospecific larvae ... | 2012 | 22737236 |
| incompatibility and competitive exclusion of genomic segments between sibling drosophila species. | the extent and nature of genetic incompatibilities between incipient races and sibling species is of fundamental importance to our view of speciation. however, with the exception of hybrid inviability and sterility factors, little is known about the extent of other, more subtle genetic incompatibilities between incipient species. here we experimentally demonstrate the prevalence of such genetic incompatibilities between two young allopatric sibling species, drosophila simulans and d. sechellia. ... | 2012 | 22761593 |