Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| evolution of wolbachia-induced cytoplasmic incompatibility in drosophila simulans and d. sechellia. | the intracellular bacterium wolbachia invades arthropod host populations through various mechanisms, the most common of which being cytoplasmic incompatibility (ci). ci involves elevated embryo mortality when infected males mate with uninfected females or females infected with different, incompatible wolbachia strains. the present study focuses on this phenomenon in two drosophila species: d. simulans and d. sechellia. drosophila simulans populations are infected by several wolbachia strains, in ... | 2002 | 12389718 |
| sex-ratio drive in drosophila simulans: variation in segregation ratio of x chromosomes from a natural population. | the sex-ratio trait that exists in a dozen drosophila species is a case of naturally occurring x chromosome drive that causes males to produce female-biased progeny. autosomal and y polymorphism for suppressors are known to cause variation in drive expression, but the x chromosome polymorphism has never been thoroughly investigated. we characterized 41 x chromosomes from a natural population of drosophila simulans that had been transferred to a suppressor-free genetic background. we found two cl ... | 2002 | 12454068 |
| characterization of non-cytoplasmic incompatibility inducing wolbachia in two continental african populations of drosophila simulans. | wolbachia is an endocellular bacterium infecting arthropods and nematodes. in arthropods, it invades host populations through various mechanisms, affecting host reproduction, the most common of which being cytoplasmic incompatibility (ci). ci is an embryonic mortality occurring when infected males mate with uninfected females or females infected by a different wolbachia strain. this phenomenon is observed in drosophila simulans, an intensively studied wolbachia host, harbouring at least five dis ... | 2003 | 12522425 |
| superinfection of laodelphax striatellus with wolbachia from drosophila simulans. | wolbachia are maternally inherited, intracellular alpha-proteobacteria that infect a wide range of arthropods. they manipulate the reproduction of hosts to facilitate their spread into host populations, through ways such as cytoplasmic incompatibility (ci), parthenogenesis, feminization and male killing. the influence of wolbachia infection on host populations has attracted considerable interest in their possible role in speciation and as a potential agent of biological control. in this study, w ... | 2003 | 12522428 |
| genomic effects of nucleotide substitutions in drosophila simulans. | selective fixation of beneficial mutations reduces levels of linked, neutral variation. the magnitude of this "hitchhiking effect" is determined by the strength of selection and the recombination rate between selected and neutral sites. thus, depending on the values of these parameters and the frequency with which directional selection occurs, the genomic scale over which directional selection reduces levels of linked variation may vary widely. here we present a permutation-based analysis of nuc ... | 2002 | 12524346 |
| evolution of gene expression in the drosophila melanogaster subgroup. | little is known about broad patterns of variation and evolution of gene expression during any developmental process. here we investigate variation in genome-wide gene expression among drosophila simulans, drosophila yakuba and four strains of drosophila melanogaster during a major developmental transition--the start of metamorphosis. differences in gene activity between these lineages follow a phylogenetic pattern, and 27% of all of the genes in these genomes differ in their developmental gene e ... | 2003 | 12548287 |
| wolbachia distribution and cytoplasmic incompatibility during sperm development: the cyst as the basic cellular unit of ci expression. | the growth and distribution of the intracellular microbe wolbachia pipientis during spermatogenesis in several different host/symbiont genetic combinations in drosophila melanogaster and drosophila simulans is described. considerable intra- and inter-strain variation in wolbachia density and tissue distribution was observed. wolbachia were found inside spermatocytes and spermatids or within the somatic cyst cells surrounding the germ cells. some strains displayed both tissue distributions. high ... | 2003 | 12559491 |
| the evolutionary history of drosophila buzzatii. xxxiv. the distribution of the retrotransposon osvaldo in original and colonizing populations. | the frequency distribution of the retrotransposon osvaldo in the haploid genome of drosophila buzzatii has been studied in five natural populations from the iberian peninsula and six natural populations from argentina. in iberian populations, osvaldo insertion sites do not follow a poisson distribution, most probably due to eight euchromatic sites with high occupancy, found in all populations. the estimated alpha and beta parameters, which measure the relative importance of drift and negative se ... | 1998 | 12572617 |
| patterns of dna sequence polymorphism at sod vicinities in drosophila melanogaster: unraveling the footprint of a recent selective sweep. | we survey dna sequence polymorphisms at the sod locus and four neighboring regions of drosophila melanogaster, spanning 55,513 base pairs (bp), in 15 strains from a natural population, plus one reference laboratory strain and one strain of drosophila simulans. our objective is to characterize a proposed selective sweep that occurred at a locus close to sod in d. melanogaster and to characterize the strength of the selection event, its time, and the size of the hitchhiked region. two regions, 181 ... | 2003 | 12578968 |
| worldwide distribution of transposable element copy number in natural populations of drosophila simulans. | transposable elements (tes), which promote various kinds of mutations, constitute a large fraction of the genome. how they invade natural populations and species is therefore of fundamental importance for understanding the dynamics of genetic diversity and genome composition. on the basis of 85 samples of natural populations of drosophila simulans, we report the distributions of the genome insertion site numbers of nine tes that were chosen because they have a low average number of sites. most p ... | 2003 | 12643577 |
| cloning and characterization of a gene encoding glutathione-regulated potassium-efflux system protein kefkl from the endosymbiont wolbachia. | the maternally inherited intracellular symbiont wolbachia is well known for inducing a variety of reproductive and developmental abnormalities in the diverse arthropod hosts it infects. it has been implicated in causing cytoplasmic incompatibility (ci), parthenogenesis, feminization of genetic males and male killing in different hosts. however, the molecular mechanisms by which this fastidious bacterium causes these abnormalities have not yet been determined. in our study, representational diffe ... | 2002 | 12652910 |
| the evolution of autosomal suppressors of sex-ratio drive in drosophila simulans. | sex-ratio drive, which results in males siring female-biased progeny, has been reported in several drosophila species, including d. simulans. it is caused by x-linked drivers that prevent the production of y-bearing sperm. in natural populations of d. simulans, the drivers are usually cryptic, because their spread has elicited the evolution of drive suppressors. we investigated autosomal suppression in flies from madagascar, réunion and kenya. autosomal suppressors were found in all three places ... | 2003 | 12656572 |
| variability on the dot chromosome in the drosophila simulans clade. | a recent study suggested that recent nuclear gene introgression between drosophila simulans and d. mauritiana may have obscured efforts to estimate the phylogeny of the species of the d. simulans clade, which includes these two species and d. sechellia. here, we report sequence variation of an intron of the eyeless gene in this species group. this gene should introgress freely between these species because it is not linked to any known barriers to gene exchange. we have also reevaluated levels o ... | 2003 | 12733664 |
| mitochondrial genotype affects fitness in drosophila simulans. | drosophila simulans is known to harbor three distinct mitochondrial dna (mtdna) haplotype groups (sii, -ii, and -iii) with nearly 3.0% interhaplotypic divergence but <0.06% intrahaplotypic diversity. with the large amount of genetic variation in this system, the potential power to detect intraspecific fitness differences in fly lines that carry distinct haplotypes is great. we test three life-history traits on fly lines with known sequence differences in the mtdna genome after controlling the nu ... | 2003 | 12750331 |
| genetic studies on premating isolation in drosophila simulans. ii. a d. simulans line highly crossable to males of d. yakuba and d. teissieri. | females of the s1 line of drosophila simulans, an isofemale line from a natural population at mishima, japan, were found to show high crossability to males of d. yakuba and d. teissieri. with d. yakuba males, 24.0-58.5% of the s1 females were inseminated, while the rate was only 0.0-6.3% for the control lines. the high crossability was ascribed to the genes on the x and third chromosomes. with d. teissieri males, 38.0-51.5% of the s1 females were inseminated, while the rate was only 0.0-6.2% for ... | 2003 | 12773816 |
| sex-dependent gene expression and evolution of the drosophila transcriptome. | comparison of the gene-expression profiles between adults of drosophila melanogaster and drosophila simulans has uncovered the evolution of genes that exhibit sex-dependent regulation. approximately half the genes showed differences in expression between the species, and among these, approximately 83% involved a gain, loss, increase, decrease, or reversal of sex-biased expression. most of the interspecific differences in messenger rna abundance affect male-biased genes. genes that differ in expr ... | 2003 | 12805547 |
| sperm chromatin remodelling and wolbachia-induced cytoplasmic incompatibility in drosophila. | wolbachia pipientis is an obligate bacterial endosymbiont, which has successfully invaded approximately 20% of all insect species by manipulating their normal developmental patterns. wolbachia-induced phenotypes include parthenogenesis, male killing, and, most notably, cytoplasmic incompatibility. in the future these phenotypes might be useful in controlling or modifying insect populations but this will depend on our understanding of the basic molecular processes underlying insect fertilization ... | 2003 | 12897857 |
| genetic dissection of hybrid incompatibilities between drosophila simulans and d. mauritiana. i. differential accumulation of hybrid male sterility effects on the x and autosomes. | the genetic basis of hybrid incompatibility in crosses between drosophila mauritiana and d. simulans was investigated to gain insight into the evolutionary mechanisms of speciation. in this study, segments of the d. mauritiana third chromosome were introgressed into a d. simulans genetic background and tested as homozygotes for viability, male fertility, and female fertility. the entire third chromosome was covered with partially overlapping segments. many segments were male sterile, while none ... | 2003 | 12930747 |
| genetic dissection of hybrid incompatibilities between drosophila simulans and d. mauritiana. ii. mapping hybrid male sterility loci on the third chromosome. | hybrid male sterility (hms) is a rapidly evolving mechanism of reproductive isolation in drosophila. here we report a genetic analysis of hms in third-chromosome segments of drosophila mauritiana that were introgressed into a d. simulans background. qualitative genetic mapping was used to localize 10 loci on 3r and a quantitative trait locus (qtl) procedure (multiple-interval mapping) was used to identify 19 loci on the entire chromosome. these genetic incompatibilities often show dominance and ... | 2003 | 12930748 |
| natural selection drives drosophila immune system evolution. | evidence from disparate sources suggests that natural selection may often play a role in the evolution of host immune system proteins. however, there have been few attempts to make general population genetic inferences on the basis of analysis of several immune-system-related genes from a single species. here we present dna polymorphism and divergence data from 34 genes thought to function in the innate immune system of drosophila simulans and compare these data to those from 28 nonimmunity gene ... | 2003 | 12930753 |
| genetics of drosophila simulans male mating discrimination in crosses with d. melanogaster. | the genetic bases of sexual isolation between drosophila melanogaster and d. simulans have been mainly studied in females, and there is little information about the role of the males in interspecific mating discrimination. using d. simulans synthetic lines with compound chromosomes from a population of the seychelles islands (high frequency of interspecific mating) and a multimarker strain (low frequency), we show that d. simulans males play an important role in discriminating d. melanogaster fe ... | 2003 | 12939619 |
| pseudotumors and fitness in drosophila melanogaster and drosophila simulans. | 1961 | 13722547 | |
| chromosomal monomorphism in brazilian and argentine populations of drosophila simulans and drosophila repleta. | 1964 | 14239802 | |
| conservation and divergence of the genetic structure of larval foraging behaviour in two species of the drosophila simulans clade. | larvae of the sibling species drosophila simulans and d. mauritiana have rates of locomotor and feeding activity that are closely similar. comparisons of the trait means for intra- and interspecific hybrids show that significant epistatic interactions affect both characters when the genomes of the two species are combined. the phenotypic variances of progenies obtained by backcrossing the interspecific hybrids to their respective parent species show that appreciable genetic turnover affecting fo ... | 2004 | 14508499 |
| large-scale adaptive hitchhiking upon high recombination in drosophila simulans. | natural selection is expected to leave a characteristic footprint on neighboring nucleotide variation through the effects of genetic linkage. the size of the region affected is proportional to the strength of selection and greatly reduced with the recombinational distance from the selected site. thus, the genomic footprint of selection is generally believed to be restricted to a small dna stretch in normal and highly recombining regions. here, we study the effect of selection on linked polymorph ... | 2003 | 14573496 |
| [random amplified polymorphic dna (rapd) analysis of drosophila simulans in the mainland of china]. | the widespread distribution of drosophila simulans in the mainland of china was found recently. random amplified polymorphic dna (rapd) was used to analyzed dna polymorphisms of 38 drosophila simulans populations collected from the mainland of china. the origins of d. simulans in china were also discussed. using 40 arbitary primers (10 bp), we made pcr amplifications under the optimized reaction conditions for rapd that had been established in our laboratory. our molecular phylogenetic tree cons ... | 2003 | 14579539 |
| sequential evolution of a symbiont inferred from the host: wolbachia and drosophila simulans. | this study aims to unravel the biogeography of a model symbiont/host system by exploiting the prediction that a symbiont will leave a signature of infection on the host. specifically, a global sample of 1,442 drosophila simulans from 33 countries and 64 sampling localities was employed to infer the phylogeography of the maternally inherited alpha-proteobacteria wolbachia. phylogenetic analyses, from three symbiont genes and 24 mtdna genomes (excluding the a + t-rich region), showed that each of ... | 2004 | 14660690 |
| genetic dissection of hybrid incompatibilities between drosophila simulans and d. mauritiana. iii. heterogeneous accumulation of hybrid incompatibilities, degree of dominance, and implications for haldane's rule. | the genetic basis of haldane's rule was investigated through estimating the accumulation of hybrid incompatibilities between drosophila simulans and d. mauritiana by means of introgression. the accumulation of hybrid male sterility (hms) is at least 10 times greater than that of hybrid female sterility (hfs) or hybrid lethality (hl). the degree of dominance for hms and hl in a pure d. simulans background is estimated as 0.23-0.29 and 0.33-0.39, respectively; that for hl in an f1 background is un ... | 2003 | 14686533 |
| a mariner-like element with a 5' lesion in drosophila simulans. | the unstable white-s2 (ws2) allele of the white gene occurred spontaneously in the s2 strain of drosophila simulans. this mutation was caused by insertion of the submariner element, a mariner-like element with an abnormal tandem duplication of the 5' inverted terminal repeat (itr). although it has an incomplete itr, submariner excises efficiently. the rate of somatic reversion, estimated by the number of eye-color mosaic flies, was 79.9%, and the reversion frequency in the germline was 0.6%. the ... | 2003 | 14686602 |
| influence of two wolbachia strains on population structure of east african drosophila simulans. | drosophila simulans is hypothesized to have originated in continental east africa or madagascar. in this study, we investigated evolutionary forces operating on mitochondrial dna (mtdna) in populations of d. simulans from zimbabwe, malawi, tanzania, and kenya. variation in mtdna may be affected by positive selection, background selection, demographic history, and/or any maternally inherited factor such as the bacterial symbiont wolbachia. in east africa, the wri and wma wolbachia strains associa ... | 2003 | 14704179 |
| wolbachia transfer from rhagoletis cerasi to drosophila simulans: investigating the outcomes of host-symbiont coevolution. | wolbachia is an endosymbiont of diverse arthropod lineages that can induce various alterations of host reproduction for its own benefice. cytoplasmic incompatibility (ci) is the most common phenomenon, which results in embryonic lethality when males that bear wolbachia are mated with females that do not. in the cherry fruit fly, rhagoletis cerasi, wolbachia seems to be responsible for previously reported patterns of incompatibility between populations. here we report on the artificial transfer o ... | 2004 | 14711652 |
| strong selective sweep associated with a transposon insertion in drosophila simulans. | we know little about several important properties of beneficial mutations, including their mutational origin, their phenotypic effects (e.g., protein structure changes vs. regulatory changes), and the frequency and rapidity with which they become fixed in a population. one signature of the spread of beneficial mutations is the reduction of heterozygosity at linked sites. here, we present population genetic data from several loci across chromosome arm 2r in drosophila simulans. a 100-kb segment f ... | 2004 | 14745026 |
| allometric and nonallometric components of drosophila wing shape respond differently to developmental temperature. | phenotypic plasticity of wing size and shape of drosophila simulans was analyzed across the entire range of viable developmental temperatures with procrustes geometric morphometric method. in agreement with previous studies, size clearly decreases when temperature increases. wing shape variation was decomposed into its allometric (24%) and nonallometric (76%) components, and both were shown to involve landmarks located throughout the entire wing blade. the allometric component basically revealed ... | 2003 | 14761056 |
| patterns of evolutionary constraints in intronic and intergenic dna of drosophila. | we develop methods to infer levels of evolutionary constraints in the genome by comparing rates of nucleotide substitution in noncoding dna with rates predicted from rates of synonymous site evolution in adjacent genes or other putatively neutrally evolving sites, while accounting for differences in base composition. we apply the methods to estimate levels of constraint in noncoding dna of drosophila. in introns, constraint (the estimated fraction of mutations that are selectively eliminated) is ... | 2004 | 14762063 |
| the genetics of mating recognition between drosophila simulans and d. sechellia. | during courtship, visual and chemical signals are often exchanged between the sexes. the proper exchange of such signals ensures intraspecific recognition. we have examined the genetic basis of interspecific differences in male mating behaviour and pheromone concentration between drosophila simulans and d. sechellia by using drosophila simulans/d. sechellia introgression lines. our results show a majority of quantitative trait loci (qtls) explaining variation in both male mating behaviour and ph ... | 2003 | 14768896 |
| anomalies in the expression profile of interspecific hybrids of drosophila melanogaster and drosophila simulans. | when females of drosophila melanogaster and males of drosophila simulans are mated, the male progeny are inviable, whereas the female progeny display manifold malformations and are sterile. these abnormalities result from genetic incompatibilities accumulated since the time the lineages of the species diverged, and may have their origin in aberrant gene transcription. because compensatory changes within species may obscure differences at the regulatory level in conventional comparisons of the ex ... | 2004 | 14962989 |
| [multiple allelism of the net gene in drosophila melanogaster and drosophila simulans]. | the net gene mutations are known to cause abnormal pattern of veining in all wing regions except for the first posterior cells. in natural populations of drosophila melanogaster, the net alleles were identified, which differ in phenotypic expression from standard mutations. the mutants net-extra-analis from a population belokurikha-2000 have only a single additional vein in the third posterior cell. a line from chernobyl-1986 population have another nontypical allele netch86 and shows a lower de ... | 2003 | 14964828 |
| common pattern of evolution of gene expression level and protein sequence in drosophila. | sequence divergence scaled by variation within species has been used to infer the action of selection upon individual genes. applying this approach to expression, we compared whole-genome whole-body rna levels in 10 heterozygous drosophila simulans genotypes and a pooled sample of 10 d. melanogaster lines using affymetrix genechip. for 972 genes expressed in d. melanogaster, the transcript level was below detection threshold in d. simulans, which may be explained either by sequence divergence be ... | 2004 | 15034135 |
| patterns of microsatellite variability among x chromosomes and autosomes indicate a high frequency of beneficial mutations in non-african d. simulans. | we analyzed microsatellite variability at 42 x-linked and 39 autosomal loci from african and european populations of drosophila simulans. the african d. simulans harbored significantly more microsatellite variability than the european flies. in the european population, x-linked polymorphism was more reduced than autosomal variation, whereas there was no significant difference between chromosomes in the african population. previous studies also observed a similar pattern but failed to distinguish ... | 2004 | 15044592 |
| molecular evolution of x-linked accessory gland proteins in drosophila pseudoobscura. | in drosophila melanogaster and drosophila simulans, positive darwinian selection drives high rates of evolution of male reproductive genes, and accessory gland proteins (acps) in particular. here, we tested whether 13 x-linked male-specific genes, 4 acps and 9 non-acps, are under selective forces in the drosophila pseudoobscura species group, much as those in the d. melanogaster group. we observed a statistically significant correlation in relative rates of nonsynonymous evolution between the tw ... | 2004 | 15073226 |
| do quantitative trait loci (qtl) for a courtship song difference between drosophila simulans and d. sechellia coincide with candidate genes and intraspecific qtl? | the genetic architecture of traits influencing sexual isolation can give insight into the evolution of reproductive isolation and hence speciation. here we report a quantitative trait loci (qtl) analysis of the difference in mean interpulse interval (ipi), an important component of the male courtship song, between drosophila simulans and d. sechellia. using a backcross analysis, we find six qtl that explain a total of 40.7% of the phenotypic variance. three candidate genes are located in the int ... | 2004 | 15082549 |
| signature of selective sweep associated with the evolution of sex-ratio drive in drosophila simulans. | in several drosophila species, the xy mendelian ratio is disturbed by x-linked segregation distorters (sex-ratio drive). we used a collection of recombinants between a nondistorting chromosome and a distorting x chromosome originating from the seychelles to map a candidate sex-ratio region in drosophila simulans using molecular biallelic markers. our data were compatible with the presence of a sex-ratio locus in the 7f cytological region. using sequence polymorphism at the nrg locus, we showed t ... | 2004 | 15082554 |
| drosophila melanogaster, drosophila simulans: so similar yet so different. | during the last two decades, the two cosmopolitan species drosophila melanogaster and drosophila simulans have been compared with regard to numerous characteristics, ranging from their geographic distribution and ecology to their dna polymorphism. various traits have been compared, including morphology, physiology, sexual behavior, allozymes and other proteins, chromosomal inversions, mitochondrial and nuclear dna, transposable elements, wolbachia etc. such comparisons reveal similarities and di ... | 2004 | 15088643 |
| patterns of microsatellite variability in the drosophila melanogaster complex. | forty-seven microsatellite loci were amplified in drosophila melanogaster, drosophila simulans, drosophila mauritiana and drosophila sechellia. the two cosmopolitan species d. melanogaster and d. simulans were found to be the most variable ones, followed by d. mauritiana and d. sechellia. a model based clustering algorithm was applied to the population samples of d. melanogaster, d. simulans and d. sechellia. no evidence for population substructure was detected within species--most likely due to ... | 2004 | 15088648 |
| the sex-ratio trait and its evolution in drosophila simulans: a comparative approach. | sex-ratio x chromosomes, which prevent the production of y-bearing sperm, have been identified in a dozen drosophila species covering a wide phylogenetic range. it has not yet been established whether the same ancestral genetic system underlies this type of meiotic drive across the genus, but the biological characteristics and the evolutionary history of species undoubtedly determine the fate of x-linked drivers. the intragenomic conflict they trigger contributes to geographical variation in d. ... | 2004 | 15088650 |
| a reanalysis of protein polymorphism in drosophila melanogaster, d. simulans, d. sechellia and d. mauritiana: effects of population size and selection. | comparison of synonymous and nonsynonymous variation/substitution within and between species at individual genes has become a widely used general approach to detect the effect of selection versus drift. the sibling species group comprised of two cosmopolitan (drosophila melanogaster and drosophila simulans) and two island (drosophila mauritiana and drosophila sechellia) species has become a model system for such studies. in the present study we reanalyzed the pattern of protein variation in thes ... | 2004 | 15088651 |
| transposable element dynamics in two sibling species: drosophila melanogaster and drosophila simulans. | transposable elements (tes) in the two sibling species, drosophila melanogaster and d. simulans, differ considerably in amount and dynamics, with d. simulans having a smaller amount of tes than d. melanogaster. several hypotheses have been proposed to explain these differences, based on the evolutionary history of the two species, and claim differences either in the effective size of the population or in genome characteristics. recent data suggest, however, that the higher amount of tes in d. me ... | 2004 | 15088652 |
| wanderings of hobo: a transposon in drosophila melanogaster and its close relatives. | the transposon hobo is present in the genomes of drosophila melanogaster and drosophila simulans (and d. mauritiana and probably d. sechellia, based on southern blots) as full-size elements and internally deleted copies. the full-size melanogaster, simulans and mauritiana hobo elements are 99.9% identical at the dna sequence level, and internally deleted copies in these species essentially differ only in having deletions. in addition to these, hobo-related sequences are present and detectable wi ... | 2004 | 15088653 |
| mitotic and polytene chromosomes: comparisons between drosophila melanogaster and drosophila simulans. | this review deals with the differences between drosophila melanogaster and drosophila simulans in their mitotic and polytene chromosomes. the description of the mitotic karyotypes of d. melanogaster and d. simulans is mainly based on the methods that allow to differentiate their euchromatin from their heterochromatin: banding patterns, distribution of satellite dnas and location of the rdna. the polytene chromosomes karyotypes are known for many years to differ by a major paracentric inversion o ... | 2004 | 15088654 |
| ecological and genetic interactions in drosophila-parasitoids communities: a case study with d. melanogaster, d. simulans and their common leptopilina parasitoids in south-eastern france. | drosophila species are attacked by a number of parasitoid wasps, which constitute an important factor of population regulation. since drosophila melanogaster and drosophila simulans share common parasitoid species, their ecology and evolution can hardly be understood without considering parasitoids. after a short review of data available on drosophila-parasitoid interactions involving d. melanogaster and d. simulans as hosts, we report field and laboratory experiments investigating the ecologica ... | 2004 | 15088657 |
| molecular analysis of circadian clocks in drosophila simulans. | the drosophila simulans per gene is polymorphic for the length of a repeat that encodes a series of thr-gly pairs. we have examined the circadian behaviour of flies derived from isofemale lines that carry the major variants, and find some significant differences in the way that the clock responds to temperature challenge, that might relate to the observed frequencies of these alleles in nature. we also observe that circadian thermal behaviour is also predictably influenced by subtle differences ... | 2004 | 15088659 |
| a mutation in drosophila simulans that lengthens the circadian period of locomotor activity. | the length of the thr-gly repeat within the period gene of drosophilids, coevolves with its immediate flanking region to maintain the temperature compensation of the fly circadian clock. in drosophila simulans, balancing selection appears to maintain a polymorphism in this region, with three repeat lengths carrying 23, 24 or 25 thr-gly pairs, each in complete linkage disequilibrium with a distinctive flanking region amino acid moiety. we wondered whether separating a specific length repeat from ... | 2004 | 15088660 |
| the nature of genetic variation in sex and reproduction-related genes among sibling species of the drosophila melanogaster complex. | much is known about the biology of drosophila melanogaster. as a model organism, a comprehensive understanding of its development, physiology and reproduction has been acquired. as a result, a broad variety of transferable genetic tools and information has allowed sibling species of the d. melanogaster complex to emerge as an important speciation model system. by comparing d. melanogaster with its close relative, drosophila simulans, as well as its other sibling species, we are beginning to unde ... | 2004 | 15088662 |
| genetics of hybrid inviability and sterility in drosophila: dissection of introgression of d. simulans genes in d. melanogaster genome. | interspecific crosses between drosophila melanogaster and drosophila simulans usually produce sterile unisexual hybrids. the barrier preventing genetic analysis of hybrid inviability and sterility has been taken away by the discovery of a d. simulans strain which produces fertile female hybrids. d. simulans genes in the cytological locations of 21a1 to 22c1-23b1 and 30f3-31c5 to 36a2-7 have been introgressed into the d. melanogaster genetic background by consecutive backcrosses. flies heterozygo ... | 2004 | 15088663 |
| a new hybrid rescue allele in drosophila melanogaster. | crosses of drosophila melanogaster females to males of its sibling species drosophila simulans, drosophila mauritiana and drosophila sechellia produce no sons and daughters that are viable only at low temperatures. we describe here a novel rescue allele df(1)ep307-1-2 isolated on the basis of its suppression of high temperature hybrid female lethality. df(1)ep307-1-2 also rescues hybrid males to the pharate adult stage, the same stage at which it is lethal to d. melanogaster pure species males. ... | 2004 | 15088664 |
| why there is a one-way crossability between d. melanogaster and d. simulans? an ontogenic explanation. | in the drosophila melanogaster complex, females d. melanogaster mate relatively easily with males drosophila simulans but the reciprocal cross is rare. the species sexual isolation is mainly based on chemical and acoustic signal exchanges between partners. the male side of this communication is investigated in this paper in order to understand the asymmetry. in d. melanogaster the acoustic signature is highly significant, and is synergistically reinforced by the chemical signal. in d. simulans t ... | 2004 | 15088667 |
| evolutionary genetics: mobile dnas as sources of adaptive change? | mobile dnas are potent sources of mutation in wild populations, but seem only rarely to have been used in adaptive evolution. a new study has revealed a mobile dna insertion in drosophila simulans that is associated with an apparent selective sweep and an elevation in expression level of an adjacent gene which creates insecticide resistance. | 2004 | 15120086 |
| nucleotide variation and recombination along the fourth chromosome in drosophila simulans. | the fourth chromosome of drosophila melanogaster and its sister species are believed to be nonrecombining and have been a model system for testing predictions of the effects of selection on linked, neutral variation. we recently examined nucleotide variation along the chromosome of d. melanogaster and revealed that a low average level of recombination could be associated with considerably high levels of nucleotide variation. in this report, we further investigate the variation along the fourth c ... | 2004 | 15126398 |
| strain-specific quantification of wolbachia density in aedes albopictus and effects of larval rearing conditions. | the density of the endosymbiont wolbachia can influence the expression of the crossing sterilities known as cytoplasmic incompatibility (ci), and also its rate of maternal transmission. aedes albopictus mosquitoes contain a superinfection with the wolbachia strains walba and walbb. a strain-specific real-time quantitative pcr assay was developed and used to quantify relative wolbachia strain densities within individual mosquitoes. the walbb strain was consistently found to be at higher density t ... | 2004 | 15157232 |
| [structural organization and distribution of symbiotic bacteria wolbachia in early embryos and ovaries of drosophila melanogaster and d. simulans]. | electron microscopic and morphometric analyses of wolbachia distribution in early embryos of drosophila flies have demonstrated that the number of bacteria in the embryo remains constant from fertilization to blastoderm, and that afterwards the symbionts could be observed only in the polar cells. each bacterium has a three-layer envelope, makes contacts with microtubules and moves through the cytoplasm following the actively dividing nuclei. it has been found for the first time that wolbachia co ... | 2004 | 15214166 |
| molecular population genetics of male accessory gland proteins in the drosophila simulans complex. | accessory gland proteins are a major component of drosophila seminal fluid. these proteins have a variety of functions and may be subject to sexual selection and/or antagonistic evolution between the sexes. most population genetic data from these proteins are from d. melanogaster and d. simulans. here, we extend the population genetic analysis of acp genes to the other simulans complex species, d. mauritiana and d. sechellia. we sequenced population samples of seven acp's from d. mauritiana, d. ... | 2004 | 15238524 |
| wolbachia and cytoplasmic incompatibility in mosquitoes. | wolbachia are maternally inherited bacteria that induce cytoplasmic incompatibility in mosquitoes, and are able to use these patterns of sterility to spread themselves through populations. for this reason they have been proposed as a gene drive system for mosquito genetic replacement, as well as for the reduction of population size or for modulating population age structure in order to reduce disease transmission. here, recent progress in the study of mosquito wolbachia is reviewed. we now have ... | 2004 | 15242714 |
| bacteriophage flux in endosymbionts (wolbachia): infection frequency, lateral transfer, and recombination rates. | the highly specialized genomes of bacterial endosymbionts typically lack one of the major contributors of genomic flux in the free-living microbial world-bacteriophages. this study yields three results that show bacteriophages have, to the contrary, been influential in the genome evolution of the most prevalent bacterial endosymbiont of invertebrates, wolbachia. first, we show that bacteriophage wo is more widespread in wolbachia than previously recognized, occurring in at least 89% (35/39) of t ... | 2004 | 15254259 |
| sex-ratio distorter of drosophila simulans reduces male productivity and sperm competition ability. | the aim of the present study was to determine whether the effects of sex-ratio segregation distorters on the fertility of male drosophila simulans can explain the contrasting success of these x-linked meiotic drivers in different populations of the species. we compared the fertility of sex-ratio and wild-type males under different mating conditions. both types were found to be equally fertile when mating was allowed, with two females per male, during the whole period of egg laying. by contrast s ... | 2004 | 15271073 |
| quantitative trait loci for sexual isolation between drosophila simulans and d. mauritiana. | sexual isolating mechanisms that act before fertilization are often considered the most important genetic barriers leading to speciation in animals. while recent progress has been made toward understanding the genetic basis of the postzygotic isolating mechanisms of hybrid sterility and inviability, little is known about the genetic basis of prezygotic sexual isolation. here, we map quantitative trait loci (qtl) contributing to prezygotic reproductive isolation between the sibling species drosop ... | 2004 | 15280240 |
| linking phylogenetics with population genetics to reconstruct the geographic origin of a species. | reconstructing ancestral geographic origins is critical for understanding the long-term evolution of a species. bayesian methods have been proposed to test biogeographic hypotheses while accommodating uncertainty in phylogenetic reconstruction. however, the problem that certain taxa may have a disproportionate influence on conclusions has not been addressed. here, we infer the geographic origin of drosophila simulans using 2,014 bp of the period locus from 63 lines collected from 18 countries. w ... | 2004 | 15288072 |
| genetic architecture of wing morphology in drosophila simulans and an analysis of temperature effects on genetic parameter estimates. | the drosophila wing has been used as a model to investigate the mechanisms responsible for size and shape changes in nature, since such changes might underlie morphological evolution. to improve the understanding of wing morphological variation and the interpretation of genetic parameters estimates, we have established 59 lines from a drosophila simulans laboratory population through single pair random matings. the offspring of each line were reared at three different temperatures, and the wing ... | 2004 | 15305171 |
| differential fitness of mitochondrial dna in perturbation cage studies correlates with global abundance and population history in drosophila simulans. | mitochondria are often referred to as the powerhouse of the cell. however, research linking intraspecific differences in organismal fitness with genotypic mitochondrial dna (mtdna) variation has been hampered by the lack of variation in experimentally tractable species. this study examines whether fly lines harbouring three distinct drosophila simulans mtdna types (sii, -ii and -iii) exhibit differential fitness in laboratory perturbation cages. comparison of the pre-perturbation and post-pertur ... | 2004 | 15306370 |
| quantitative trait loci and interaction effects responsible for variation in female postmating mortality in drosophila simulans and d. sechellia introgression lines. | mating appears to inflict a cost to drosophila females, resulting in a reduction of their lifespan shortly after mating. males from different chromosome extracted lines differ significantly in their detrimental effects on postmating female survival, and seminal fluid proteins produced in the male accessory glands are at least partially responsible for the effect. this suggests that there is a genetic basis underlying the male inflicted effect on female's postmating mortality. however, the genes ... | 2005 | 15354189 |
| identification of a locus under complex positive selection in drosophila simulans by haplotype mapping and composite-likelihood estimation. | the recent action of positive selection is expected to influence patterns of intraspecific dna sequence variation in chromosomal regions linked to the selected locus. these effects include decreased polymorphism, increased linkage disequilibrium, and an increased frequency of derived variants. these effects are all expected to dissipate with distance from the selected locus due to recombination. therefore, in regions of high recombination, it should be possible to localize a target of selection ... | 2004 | 15454542 |
| association of misexpression with sterility in hybrids of drosophila simulansand d. mauritiana. | recent studies have identified genes associated with hybrid sterility and other hybrid dysfunctions, but the consequences of introgressions of these "speciation genes" are often poorly understood. previously, we identified a panel of genes that are underexpressed in sterile male hybrids of drosophila simulans and d. mauritiana relative to pure species. here, we build on this reverse-genetics approach to demonstrate that the underexpression of at least five of these genes in hybrids is associated ... | 2004 | 15486701 |
| incipient evolution of wolbachia compatibility types. | cytoplasmic incompatibility (ci) is induced in arthropods by the maternally inherited bacterium wolbachia. when infected males mate with uninfected females or with females bearing a different wolbachia variant, paternal chromosomes behave abnormally and embryos die. this pattern can be interpreted as resulting from two bacterial effects: one (usually termed mod, for modification) would affect sperm and induce embryo death, unless wolbachia is also present in the egg, which implies the existence ... | 2004 | 15521450 |
| new regulatory regions of drosophila 412 retrotransposable element generated by recombination. | there are no doubts that transposable elements (tes) have greatly influenced genomes evolution. they have, however, evolved in different ways throughout mammals, plants, and invertebrates. in mammals they have been shown to be widely present but with low transposition activity; in plants they are responsible for large increases in genome size. in drosophila, despite their low amount, transposition seems to be higher. therefore, to understand how these elements have evolved in different genomes a ... | 2005 | 15574808 |
| additivity and trans-acting effects on gene expression in male drosophila simulans. | understanding how genetic variation is maintained begins with a comprehensive description of what types of genetic variation exist, the extent and magnitude of the variation, and patterns discernable in that variation. however, such studies have focused primarily on dna sequence data and have ignored genetic variation at other hierarchical levels of genetic information. microarray technology permits an examination of genetic variation at the level of mrna abundance. utilizing a round-robin desig ... | 2004 | 15579694 |
| linkage disequilibrium and recent selection at three immunity receptor loci in drosophila simulans. | immune system genes in a california population sample of drosophila simulans were shown to bear several hallmarks of the effects of past directional selection. one potential effect of directional selection is an increase in linkage disequilibrium among the polymorphic sites that are linked to the site under selection. in this study, we focus on three d. simulans immunity loci, hmu, sr-ci/sr-ciii, and tehao, for which the polymorphic sites are in nearly perfect linkage disequilibrium, an unusual ... | 2005 | 15654108 |
| the minimal interspecific introgression resulting in male sterility in drosophila. | introgression of drosophila simulans genes into the drosophila melanogaster genome provides an ideal system for analysing genetic incompatibility between species. females and males homozygous for the introgression int(2l)s (cytologically, 30f3-31c5 to 36a2-7) are sterile. genetic dissection of the proximal part of the introgression (34d1-3 to 36a2-7) has indicated that introgressions of 0.7-1.6 mb size result in male sterility when homozygous. in the present analysis we examine the distal part o ... | 2004 | 15678745 |
| is genome size influenced by colonization of new environments in dipteran species? | genome size differences are usually attributed to the amplification and deletion of various repeated dna sequences, including transposable elements (tes). because environmental changes may promote modifications in the amount of these repeated sequences, it has been postulated that when a species colonizes new environments this could be followed by an increase in its genome size. we tested this hypothesis by estimating the genome size of geographically distinct populations of drosophila ananassae ... | 2005 | 15723678 |
| the sinbad retrotransposon from the genome of the human blood fluke, schistosoma mansoni, and the distribution of related pao-like elements. | of the major families of long terminal repeat (ltr) retrotransposons, the pao/bel family is probably the least well studied. it is becoming apparent that numerous ltr retrotransposons and other mobile genetic elements have colonized the genome of the human blood fluke, schistosoma mansoni. | 2005 | 15725362 |
| resistance to fipronil in drosophila simulans: influence of two point mutations in the rdl gaba receptor subunit. | the eyguieres 42 strain of drosophila simulans, obtained by laboratory selection, displayed approximately 20,000-fold resistance to the insecticide fipronil. molecular cloning of the cdna encoding the rdl gaba receptor subunit of this strain revealed the presence of two mutations: the rdl mutation (a301g) and an additional mutation in the third transmembrane domain (t350m). in order to assess the individual and combined roles of the two mutations in fipronil resistance, the functional properties ... | 2005 | 15748149 |
| filarial susceptibility and effects of wolbachia in aedes pseudoscutellaris mosquitoes. | the mosquito aedes pseudoscutellaris (theobald), a member of the aedes (stegomyia) scutellaris complex (diptera: culicidae), is an important vector of subperiodic wuchereria bancrofti (cobbold) (spirurida: onchocercidae), causing human lymphatic filariasis, on south pacific islands. maternal inheritance of filarial susceptibility in the complex has previously been asserted, and larval tetracycline treatment reduced susceptibility; the maternally inherited wolbachia in these mosquitoes were sugge ... | 2005 | 15752178 |
| characterization of active r2 retrotransposition in the rdna locus of drosophila simulans. | the rrna gene (rdna) loci of all arthropod lineages contain non-ltr retrotransposable elements that have evolved to specifically insert into the 28s rrna genes. extensive in vitro experiments have been conducted to investigate the mechanism of r2 retrotransposition but little is known of the insertion frequency or cellular factors that might regulate r2 activity. in this article, isofemale lines obtained from a population of drosophila simulans were surveyed for recent r2 insertions. within most ... | 2005 | 15781697 |
| [structural organization and distribution of the symbiotic bacteria wolbachia during spermatogenesis of drosophila simulans]. | electron microscopy and morphometric analysis have shown that the symbiotic bacteria wolbachia occur the testis cells during spermatogenesis and are absent in mature spermatids. bacteria did not affect the structural organization of testis cells, which have a typical morphology during morphogenesis. bacteria were distributed along the meiotic spindle microtubules near the mitochondria. they increased in number in spermatids at the stage of elongation. endosymbionts aggregated at the spermatid di ... | 2005 | 15807436 |
| similar mating and sperm displacement patterns in two highly divergent d. simulans populations from africa and europe. | the frequency of remating in drosophila melanogaster is affected by both genetic and ecological factors. we studied the remating behaviour in one european (italy) and one african (uganda) drosophila simulans population using six highly polymorphic microsatellite markers. despite that the populations were genetically distinct (f(st) = 0.18) and originated from very dissimilar ecological settings with different population densities, we inferred a very similar mating pattern. the remating parameter ... | 2005 | 15813788 |
| prospects for identifying functional variation across the genome. | the genetic factors contributing to complex trait variation may reside in regulatory, rather than protein-coding portions of the genome. within noncoding regions, snps in regulatory elements are more likely to contribute to phenotypic variation than those in nonregulatory regions. thus, it is important to be able to identify and annotate noncoding regulatory elements. dna conservation among diverged species successfully identifies noncoding regulatory regions. however, because rapidly evolving r ... | 2005 | 15851675 |
| high divergence among drosophila simulans mitochondrial haplogroups arose in midst of long term purifying selection. | we characterize the type of selection acting within and among mitochondrial lineages in five closely related drosophila species. we focus on d. simulans, where three genetically distinct mitochondrial haplogroups show high interhaplogroup divergence and low intrahaplogroup polymorphism. using maximum likelihood models we find that the branches leading to these three distinct mitochondrial groups show a significantly reduced rate of nonsynonymous relative to synonymous substitution. this interhap ... | 2005 | 15955513 |
| identification of co-regulated transcripts affecting male body size in drosophila. | factor analysis is an analytic approach that describes the covariation among a set of genes through the estimation of 'factors', which may be, for example, transcription factors, micrornas (mirnas), and so on, by which the genes are co-regulated. factor analysis gives a direct mechanism by which to relate gene networks to complex traits. using simulated data, we found that factor analysis clearly identifies the number and structure of factors and outperforms hierarchical cluster analysis. noise ... | 2005 | 15960805 |
| rapid evolution of genomic acp complement in the melanogaster subgroup of drosophila. | unusual properties of molecular evolution in reproduction-related drosophila genes, including atypically rapid rates of protein evolution, support the idea that natural selection plays an important role in divergence of reproductive function in drosophila. we used subtractive hybridization to investigate another potential side of evolution of the male reproductive transcriptome. we carried out a screen for genes with much greater transcript abundance in drosophila simulans reproductive tracts th ... | 2005 | 15987879 |
| a rapid decrease in number of the complete ninja element and concomitant increase of the defective element in a strain of drosophila simulans. | the ninja element, originally isolated from an unstable white mutant strain white-milky (w(mky)) of drosophila simulans, is a member of the retrotransposon family with long terminal repeats (ltrs). we show that ninja is present in high copy numbers in the w(mky)-derivative sublines white-chocolate (w(cho)) and white-persimmonl (w(psm1)), in a low copy number in another derivative subline white-milky 3 (w(mky3)), and in only a few copies in a wild type strain. we have cloned the ninja elements fr ... | 2005 | 16011008 |
| historical biogeography of drosophila simulans based on y-chromosomal sequences. | y-chromosomal sequences have been used for phylogeographic studies in humans and other mammals, but so far have been ignored as a source of historical information in drosophila and other insects with x/y sex determination. here, we present the first phylogeographic study of drosophila simulans based on the y chromosome. geographic distribution of y-chromosomal haplotypes suggests a high degree of population subdivision within africa, as well as between the african and cosmopolitan groups of popu ... | 2006 | 16051503 |
| evidence for a functional interaction between the bari1 transposable element and the cytochrome p450 cyp12a4 gene in drosophila melanogaster. | previous studies of the genomic distribution of the transposon bari1 in drosophila melanogaster have revealed an element which is fixed at division 91f in over 90 lab and natural populations. here we report about the structural and transcriptional features of the insertion site which was studied in sublines isolated from an exceptional drosophila line polymorphic for the presence/absence of bari1 at 91f. the insert is located at the 3' end of the cyp12a4 gene that belongs to the cytochrome p450 ... | 2005 | 16076534 |
| patterns of intron sequence evolution in drosophila are dependent upon length and gc content. | introns comprise a large fraction of eukaryotic genomes, yet little is known about their functional significance. regulatory elements have been mapped to some introns, though these are believed to account for only a small fraction of genome wide intronic dna. no consistent patterns have emerged from studies that have investigated general levels of evolutionary constraint in introns. | 2005 | 16086849 |
| geographic differentiation in the house fly estimated by microsatellite and mitochondrial variation. | gene flow over very large geographic scales has been investigated in few species. examples include drosophila melanogaster, drosophila subobscura, drosophila simulans, and the mediterranean fruit fly (ceratitis capitata). the cosmopolitan house fly, a highly vagile, fecund, colonizing species offers an additional exemplar. genotypes at seven microsatellite loci were scored in 14 widely separated natural house fly populations from the nearctic, neotropics, afrotropics, palearctic, and asia. allel ... | 2008 | 16135710 |
| quantitative trait loci for cuticular hydrocarbons associated with sexual isolation between drosophila simulans and d. sechellia. | the identification of genes with large effects on sexual isolation and speciation is an important link between classic evolutionary genetics and molecular biology. few genes that affect sexual isolation and speciation have been identified, perhaps because many traits influencing sexual isolation are complex behaviors. cuticular hydrocarbons (chs) of species of the drosophila melanogaster group play a large role in sexual isolation by functioning as contact pheromones influencing mate recognition ... | 2005 | 16143629 |
| the evolution of antifungal peptides in drosophila. | an essential component of the immune system of animals is the production of antimicrobial peptides (amps). in vertebrates and termites the protein sequence of some amps evolves rapidly under positive selection, suggesting that they may be coevolving with pathogens. however, antibacterial peptides in drosophila tend to be highly conserved. we have inferred the selection pressures acting on drosophila antifungal peptides (drosomycins) from both the divergence of drosomycin genes within and between ... | 2005 | 16157672 |
| drosophila simulans as a novel model for studying mitochondrial metabolism and aging. | mitochondria generate much of the cellular energy through the process of oxidative phosphorylation (oxphos). oxphos function may be affected by a mutation in any of the mitochondrial (mt) dna encoded genes and/or nuclear encoded genes that produce proteins imported into the mitochondrion that form (or assemble) the five complexes located on the inner mitochondrial membrane. decreasing mitochondrial oxphos efficiency, defined as the amount of inorganic phosphate incorporated into atp per mole of ... | 2005 | 16169180 |
| patterns of evolution of genes disrupted in expression in drosophila species hybrids. | divergence between species in regulatory pathways may contribute to hybrid incompatibilities such as sterility. consistent with this idea, genes involved in male fertility often evolve faster than most other genes both in amino acid sequence and in expression. previously, we identified a panel of male-specific genes under-expressed in sterile male hybrids of drosophila simulans and d. mauritiana relative to pure species, and we showed that this under-expression is associated with infertility. in ... | 2005 | 16174330 |
| nuclear-mitochondrial epistasis and drosophila aging: introgression of drosophila simulans mtdna modifies longevity in d. melanogaster nuclear backgrounds. | under the mitochondrial theory of aging, physiological decline with age results from the accumulated cellular damage produced by reactive oxygen species generated during electron transport in the mitochondrion. a large body of literature has documented age-specific declines in mitochondrial function that are consistent with this theory, but relatively few studies have been able to distinguish cause from consequence in the association between mitochondrial function and aging. since mitochondrial ... | 2006 | 16219776 |
| efficient procedure for purification of obligate intracellular wolbachia pipientis and representative amplification of its genome by multiple-displacement amplification. | bacteria belonging to the genus wolbachia are obligatory microendocytobionts that infect a variety of arthropods and a majority of filarial nematode species, where they induce reproductive alterations or establish a mutualistic symbiosis. although two whole genome sequences of wolbachia pipientis, for strain wmel from drosophila melanogaster and strain wbm from brugia malayi, have been fully completed and six other genome sequencing projects are ongoing (http://www.genomesonline.org/index.cgi?wa ... | 2005 | 16269725 |
| rapid evolution and gene-specific patterns of selection for three genes of spermatogenesis in drosophila. | hybrid males resulting from crosses between closely related species of drosophila are sterile. the f1 hybrid sterility phenotype is mainly due to defects occurring during late stages of development that relate to sperm individualization, and so genes controlling sperm development may have been subjected to selective diversification between species. it is also possible that genes of spermatogenesis experience selective constraints given their role in a developmental pathway. we analyzed the molec ... | 2006 | 16357040 |
| organization of the sex-ratio meiotic drive region in drosophila simulans. | sex-ratio meiotic drive is the preferential transmission of the x chromosome by xy males, which occurs in several drosophila species and results in female-biased progeny. although the trait has long been known to exist, its molecular basis remains completely unknown. here we report a fine-mapping experiment designed to characterize the major drive locus on a sex-ratio x chromosome of drosophila simulans originating from the seychelles (xsr6). this primary locus was found to contain two interacti ... | 2006 | 16387875 |