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1.
ISME J ; 14(1): 217-229, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31624341

RESUMO

The taxonomic composition of microbial communities in animals varies among animal species, but the contribution of interspecific differences in filtering of the microbial pool by the animal host to this variation is uncertain. Here, we demonstrate significant interspecific variation in microbial community composition among laboratory-reared Drosophila species that was not related to host phylogeny. Complementary reciprocal transfer experiments yielded different microbial communities for a single microbiota administered to homologous and heterologous hosts (i.e., the same and different Drosophila species from which the microbiota was derived), indicative of among-host species differences in traits that shape microbiota composition. The difference in microbiota composition between homologous and heterologous hosts was not greater for distantly related than for closely related host species pairs. Furthermore, Drosophila survival to adulthood was significantly reduced in heterologous associations relative to homologous associations and microbiologically sterile flies, suggesting that microbial taxa that are advantageous for their homologous host species can be deleterious for other host species. We conclude that drosophilid flies display robust among-host species variation in host controls over microbiota composition that has diversified in response to selection pressures which are not tracked by host phylogeny.


Assuntos
Drosophila/microbiologia , Especificidade de Hospedeiro , Microbiota , Animais , Drosophila/classificação , Filogenia
2.
BMC Evol Biol ; 19(1): 204, 2019 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-31694548

RESUMO

BACKGROUND: Disentangling the selective factors shaping adaptive trait variation is an important but challenging task. Many studies-especially in Drosophila-have documented trait variation along latitudinal or altitudinal clines, but frequently lack resolution about specific environmental gradients that could be causal selective agents, and often do not investigate covariation between traits simultaneously. Here we examined variation in multiple macroecological factors across geographic space and their associations with variation in three physiological traits (desiccation resistance, UV resistance, and pigmentation) at both population and species scales, to address the role of abiotic environment in shaping trait variation. RESULTS: Using environmental data from collection locations of three North American Drosophila species-D. americana americana, D. americana texana and D. novamexicana-we identified two primary axes of macroecological variation; these differentiated species habitats and were strongly loaded for precipitation and moisture variables. In nine focal populations (three per species) assayed for each trait, we detected significant species-level variation for both desiccation resistance and pigmentation, but not for UV resistance. Species-level trait variation was consistent with differential natural selection imposed by variation in habitat water availability, although patterns of variation differed between desiccation resistance and pigmentation, and we found little evidence for pleiotropy between traits. CONCLUSIONS: Our multi-faceted approach enabled us to identify potential agents of natural selection and examine how they might influence the evolution of multiple traits at different evolutionary scales. Our findings highlight that environmental factors influence functional trait variation in ways that can be complex, and point to the importance of studies that examine these relationships at both population- and species-levels.


Assuntos
Drosophila/genética , Drosophila/fisiologia , Animais , Drosophila/classificação , Ecossistema , Feminino , Variação Genética , Masculino , América do Norte , Fenótipo , Pigmentação , Seleção Genética
3.
Analyst ; 144(19): 5848-5855, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31482871

RESUMO

The carbon-carbon double bond positions of unsaturated fatty acids can have markedly different effects on biological function and also serve as biomarkers of disease pathology, dietary history, and species identity. As such, there is great interest in developing methods for the facile determination of double bond position for natural product chemistry, the pharmaceutical industry, and forensics. We paired ozonolysis with direct analysis in real time mass spectrometry (DART MS) to cleave and rapidly identify carbon-carbon double bond position in fatty acids, fatty alcohols, wax esters, and crude fatty acid extracts. In addition, ozone exposure time and DART ion source temperature were investigated to identify optimal conditions. Our results reveal that brief, offline exposure to ozone-generated aldehyde and carboxylate products that are indicative of carbon-carbon double bond position. The relative abundance of diagnostic fragments quantitatively reflects the ratios of isobaric fatty acid positional isomers in a mixture with a correlation coefficient of 0.99. Lastly, the unsaturation profile generated from unfractionated, fatty acid extracts can be used to differentiate insect species and populations. The ability to rapidly elucidate lipid double bond position by combining ozonolysis with DART MS will be useful for lipid structural elucidation, assessing isobaric purity, and potentially distinguishing between animals fed on different diets or belonging to different ecological populations.


Assuntos
Ácidos Graxos Insaturados/química , Ozônio/química , Animais , Drosophila/química , Drosophila/classificação , Álcoois Graxos/química , Isomerismo , Espectrometria de Massas/métodos , Ceras/química
4.
Int J Biol Macromol ; 138: 912-918, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31362022

RESUMO

Fruit flies (Drosophilidae: Drosophila) are commonly found in daily life and have long been used as model organisms in biology researches. Drosophila mercatorum is one important member of the Drosophila genus and has been used to study centrosome assembly of cells. In this study, we sequenced and analyzed the mitochondrial genome (mitogenome) of D. mercatorum, finding that it contains the typical structure of 37 genes and a control region. The arrangement of mitochondrial genes is in accordance with that in other Drosophila species, which is considered the ancestral organization of insects' mitogenomes. Phylogenetic analyses were performed based on 23 species of Drosophila. Our results supported two monophyletic subgenera, Drosophila and Sophophora, except for D. willistoni which was presented as an early offshoot of Drosophila. The topology ((D. yakuba + D. erecta) + D. melanogaster) was supported. We further compared the mitogenomes of parthenogenesis and sexual reproduction strains of D. mercatorum. However, only one synonymous mutation in COI gene was identified, indicating mitogenomic evolution is not strongly correlated with the different reproductive modes of this species. Taken together, our results demonstrate that mitogenome is an effective molecular marker that can be further used in phylogenetic studies of Drosophila and other organisms.


Assuntos
Drosophila/classificação , Drosophila/genética , Evolução Molecular , Genoma Mitocondrial , Genômica , Filogenia , Sequência de Aminoácidos , Animais , Sequência de Bases , Biologia Computacional/métodos , Feminino , Genômica/métodos , Masculino
5.
An Acad Bras Cienc ; 91(2): e20180375, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31141011

RESUMO

Drosophila suzukii is one of the main pests of small fruits in the world. An effective monitoring is fundamental to detect the presence of the fly and to predict the infestation of fruits in new areas. We evaluated the food baits Ceratrap®, Torula®, Biofruit®, Suzukii Trap®, apple cider vinegar, and a homemade mixture comprising wine, vinegar and molasses (WVM) for D. suzukii attractiveness, and if reproductive stage affects females attraction and capture in the different baits. Bait selectivity of non-target insects was assessed. The preference of adults between ripe blackberry fruit and the food baits was also evaluated. Adults showed a higher attraction (61.97% of the captured insects) to the WVM mixture than to Ceratrap® (1.32%), Torula® (0.52%), Biofruit® (13.15%), Suzukii Trap® (17.6%), and apple vinegar (5.4%). Considering the attractiveness to D. suzukii, Suzukii Trap® and apple vinegar were the most selective to non-target insects. In general, reproductively immature females showed a preference for Biofruit®, apple vinegar, and WVM, whereas mature females did not show bait preferences. Adults preferred ripe blackberry fruit over the WVM mixture. Understanding the field behavior of D. suzukii is of foremost importance to estimate insect population density and outline pest management strategies.


Assuntos
Drosophila/fisiologia , Controle de Insetos/métodos , Feromônios , Animais , Brasil , Drosophila/classificação , Feminino , Controle de Insetos/instrumentação , Masculino
6.
Genome Biol Evol ; 11(6): 1541-1551, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31076758

RESUMO

The birth-and-death evolutionary model proposes that some members of a multigene family are phylogenetically stable and persist as a single copy over time, whereas other members are phylogenetically unstable and undergo frequent duplication and loss. Functional studies suggest that stable genes are likely to encode essential functions, whereas rapidly evolving genes reflect phenotypic differences in traits that diverge rapidly among species. One such class of rapidly diverging traits are insect cuticular hydrocarbons (CHCs), which play dual roles in chemical communications as short-range recognition pheromones as well as protecting the insect from desiccation. Insect CHCs diverge rapidly between related species leading to ecological adaptation and/or reproductive isolation. Because the CHC and essential fatty acid biosynthetic pathways share common genes, we hypothesized that genes involved in the synthesis of CHCs would be evolutionary unstable, whereas those involved in fatty acid-associated essential functions would be evolutionary stable. To test this hypothesis, we investigated the evolutionary history of the fatty acyl-CoA reductases (FARs) gene family that encodes enzymes in CHC synthesis. We compiled a unique data set of 200 FAR proteins across 12 Drosophila species. We uncovered a broad diversity in FAR content which is generated by gene duplications, subsequent gene losses, and alternative splicing. We also show that FARs expressed in oenocytes and presumably involved in CHC synthesis are more unstable than FARs from other tissues. Taken together, our study provides empirical evidence that a comparative approach investigating the birth-and-death evolution of gene families can identify candidate genes involved in rapidly diverging traits between species.


Assuntos
Aldeído Oxirredutases/genética , Drosophila/enzimologia , Drosophila/genética , Evolução Molecular , Animais , Drosophila/classificação , Drosophila/crescimento & desenvolvimento , Drosophila melanogaster/enzimologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Embrião não Mamífero/enzimologia , Ácidos Graxos/biossíntese , Duplicação Gênica , Redes e Vias Metabólicas , Filogenia
7.
BMC Genomics ; 20(1): 413, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31117947

RESUMO

BACKGROUND: Insects have the capacity to adjust their physiological mechanisms during their lifetime to promote cold tolerance and cope with sublethal thermal conditions, a phenomenon referred to as thermal acclimation. The spotted wing drosophila, Drosophila suzukii, is an invasive fruit pest that, like many other species, enhances its thermotolerance in response to thermal acclimation. However, little is known about the underlying mechanisms of this plastic response. Here, we promoted flies' cold tolerance by gradually increasing acclimation duration (i.e. pre-exposure from 2 h to 9 days at 10 °C), and then compared transcriptomic responses of cold hardy versus cold susceptible phenotypes using RNA sequencing. RESULTS: Cold tolerance of D. suzukii increased with acclimation duration; the longer the acclimation, the higher the cold tolerance. Cold-tolerant flies that were acclimated for 9 days were selected for transcriptomic analyses. RNA sequencing revealed a total of 2908 differentially expressed genes: 1583 were up- and 1325 were downregulated in cold acclimated flies. Functional annotation revealed many enriched GO-terms among which ionic transport across membranes and signaling were highly represented in acclimated flies. Neuronal activity and carbohydrate metabolism were also enriched GO-terms in acclimated flies. Results also revealed many GO-terms related to oogenesis which were underrepresented in acclimated flies. CONCLUSIONS: Involvement of a large cluster of genes related to ion transport in cold acclimated flies suggests adjustments in the capacity to maintain ion and water homeostasis. These processes are key mechanisms underlying cold tolerance in insects. Down regulation of genes related to oogenesis in cold acclimated females likely reflects that females were conditioned at 10 °C, a temperature that prevents oogenesis. Overall, these results help to understand the molecular underpinnings of cold tolerance acquisition in D. suzukii. These data are of importance considering that the invasive success of D. suzukii in diverse climatic regions relates to its high thermal plasticity.


Assuntos
Aclimatação , Proteínas de Drosophila/genética , Drosophila/genética , Drosophila/fisiologia , Regulação da Expressão Gênica , Termotolerância , Animais , Temperatura Baixa , Drosophila/classificação , Perfilação da Expressão Gênica , Homeostase , Transcriptoma
8.
PLoS One ; 14(5): e0216601, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31095588

RESUMO

Drosophila community composition is complex in temperate regions with different abundance of flies and species across the growing season. Monitoring Drosophila populations provides insights into the phenology of both native and invasive species. Over a single growing season, we collected Drosophila at regular intervals and determined the number of individuals of the nine species we found in Kansas, USA. Species varied in their presence and abundance through the growing season with peak diversity occurring after the highest seasonal temperatures. We developed models for the abundance of the most common species, Drosophila melanogaster, D. simulans, D. algonquin, and the recent invasive species, D. suzukii. These models revealed that temperature played the largest role in abundance of each species across the season. For the two most commonly studied species, D. melanogaster and D. simulans, the best models indicate shifted thermal optima compared to laboratory studies, implying that fluctuating temperature may play a greater role in the physiology and ecology of these insects than indicated by laboratory studies, and should be considered in global climate change studies.


Assuntos
Comportamento Animal/fisiologia , Drosophila/classificação , Drosophila/fisiologia , Ecologia , Estações do Ano , Temperatura , Animais , Feminino , Masculino , Fenótipo , Especificidade da Espécie
9.
Curr Opin Insect Sci ; 31: 139-145, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-31109667

RESUMO

Over a thousand Drosophila species have radiated onto a wide range of feeding and breeding sites. These radiations involve adaptations for locating, accepting, and growing in hosts with highly differing characteristics. In a number of species, owing to the availability of sequenced genomes, particular steps in host specialization and genes that control them, are being identified. Many cases of specialization involve the ability to detoxify some component of the host. Examples include Drosophila sechellia and the octanoic acid in Morinda citrifolia, alpha-amanitin in mycophagous drosophilids, and the alkaloids in cactophilic species. Owing to the known ecologies of many species for which genomes exist, the Drosophila model system provides an unprecedented opportunity to simultaneously examine the genes underlying HOST LOCATION, HOST ACCEPTANCE and HOST USE, the types of selection acting upon them and any coevolutionary interactions among the genes underlying these steps.


Assuntos
Drosophila/genética , Drosophila/metabolismo , Ecossistema , Animais , Drosophila/classificação , Preferências Alimentares , Genoma de Inseto , Inativação Metabólica/genética
10.
BMC Genomics ; 20(1): 223, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30885123

RESUMO

BACKGROUND: Drosophila subobscura has long been a central model in evolutionary genetics. Presently, its use is hindered by the lack of a reference genome. To bridge this gap, here we used PacBio long-read technology, together with the available wealth of genetic marker information, to assemble and annotate a high-quality nuclear and complete mitochondrial genome for the species. With the obtained assembly, we performed the first synteny analysis of genome structure evolution in the subobscura subgroup. RESULTS: We generated a highly-contiguous ~ 129 Mb-long nuclear genome, consisting of six pseudochromosomes corresponding to the six chromosomes of a female haploid set, and a complete 15,764 bp-long mitogenome, and provide an account of their numbers and distributions of codifying and repetitive content. All 12 identified paracentric inversion differences in the subobscura subgroup would have originated by chromosomal breakage and repair, with some associated duplications, but no evidence of direct gene disruptions by the breakpoints. Between lineages, inversion fixation rates were 10 times higher in continental D. subobscura than in the two small oceanic-island endemics D. guanche and D. madeirensis. Within D. subobscura, we found contrasting ratios of chromosomal divergence to polymorphism between the A sex chromosome and the autosomes. CONCLUSIONS: We present the first high-quality, long-read sequencing of a D. subobscura genome. Our findings generally support genome structure evolution in this species being driven indirectly, through the inversions' recombination-suppression effects in maintaining sets of adaptive alleles together in the face of gene flow. The resources developed will serve to further establish the subobscura subgroup as model for comparative genomics and evolutionary indicator of global change.


Assuntos
Inversão Cromossômica , Cromossomos de Insetos , Drosophila/genética , Evolução Molecular , Genoma de Inseto , Recombinação Genética , Sintenia , Animais , Drosophila/classificação , Feminino , Fluxo Gênico , Marcadores Genéticos , Proteínas de Insetos , Masculino , Filogenia , Polimorfismo Genético
11.
Mol Ecol ; 28(7): 1826-1841, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30714238

RESUMO

Resident microorganisms are known to influence the fitness and traits of animals under controlled laboratory conditions, but the relevance of these findings to wild animals is uncertain. This study investigated the host functional correlates of microbiota composition in a wild community of three sympatric species of mycophagous drosophilid flies, Drosophila falleni, Drosophila neotestacea and Drosophila putrida. Specifically, we quantified bacterial communities and host transcriptomes by parallel 16S rRNA gene amplicon sequencing and RNA-Seq of individual flies. Among-fly variation in microbiota composition did not partition strongly by sex or species, and included multiple modules, that is, sets of bacterial taxa whose abundance varied in concert across different flies. The abundance of bacteria in several modules varied significantly with multiple host transcripts, especially in females, but the identity of the correlated host transcriptional functions differed with host species, including epithelial barrier function in D. falleni, muscle function in D. putrida, and insect growth and development in D. neotestacea. In D. neotestacea, which harbours the endosymbionts Wolbachia and Spiroplasma, Wolbachia promotes the abundance of Spiroplasma, and is positively correlated with abundance of Lactobacillales and Bacteroidales. Furthermore, most correlations between host gene expression and relative abundance of bacterial modules were co-correlated with abundance of Wolbachia (but not Spiroplasma), indicative of an interdependence between host functional traits, microbiota composition and Wolbachia abundance in this species. These data suggest that, in these natural populations of drosophilid flies, different host species interact with microbial communities in functionally different ways that can vary with the abundance of endosymbionts.


Assuntos
Bactérias/classificação , Drosophila/microbiologia , Microbiota , Wolbachia/genética , Animais , Drosophila/classificação , RNA Ribossômico 16S/genética , Spiroplasma/genética , Simbiose , Simpatria , Transcriptoma
12.
Insect Mol Biol ; 28(5): 616-627, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30793407

RESUMO

A monophyletic group of Drosophila hAT transposable elements, referred to as Herves-like, was characterized and found to be present in 46% of 57 screened Drosophila species. A remarkable characteristic of these elements is the presence of a long array of minisatellite repeats (MnRs) in both subterminal extremities of the elements. The copy number of these minisatellites was highly variable between and within populations. Twenty-three strains of Drosophila willistoni, covering its geographic distribution, were screened for polymorphism in the copy number of 5' MnRs, showing a variation from 7 to 20 repeat copies. These MnRs are well conserved among Drosophila species and probably function as transposase binding sequences, as provided by short subterminal repeats in other hAT elements. Miniature inverted repeat transposable elements were found in 27% of species carrying Herves-like elements. Phylogenetic analysis showed incongruences between transposable elements and species phylogenies, suggesting that at least four horizontal transfer events have occurred.


Assuntos
Elementos de DNA Transponíveis/genética , Drosophila/genética , Evolução Molecular , Animais , Variações do Número de Cópias de DNA , Drosophila/classificação , Transferência Genética Horizontal , Repetições Minissatélites/genética , Filogenia
13.
Mol Phylogenet Evol ; 130: 233-243, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30366088

RESUMO

Adaptive radiations provide an opportunity to examine complex evolutionary processes such as ecological specialization and speciation. While a well-resolved phylogenetic hypothesis is critical to completing such studies, the rapid rates of evolution in these groups can impede phylogenetic studies. Here we study the quinaria and testacea species groups of the immigrans-tripunctata radiation of Drosophila, which represent a recent adaptive radiation and are a developing model system for ecological genetics. We were especially interested in understanding host use evolution in these species. In order to infer a phylogenetic hypothesis for this group we sampled loci from both the nuclear genome and the mitochondrial DNA to develop a dataset of 43 protein-coding loci for these two groups along with their close relatives in the immigrans-tripunctata radiation. We used this dataset to examine their evolutionary relationships along with the evolution of feeding behavior. Our analysis recovers strong support for the monophyly of the testacea but not the quinaria group. Results from our ancestral state reconstruction analysis suggests that the ancestor of the testacea and quinaria groups exhibited mushroom-feeding. Within the quinaria group, we infer that transition to vegetative feeding occurred twice, and that this transition did not coincide with a genome-wide change in the rate of protein evolution.


Assuntos
Drosophila/classificação , Filogenia , Animais , DNA Mitocondrial/genética , Drosophila/genética , Evolução Molecular , Comportamento Alimentar , Genoma de Inseto , Proteínas de Insetos/genética , Especificidade da Espécie
14.
Genes Brain Behav ; 18(1): e12487, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29797548

RESUMO

While social experience has been shown to significantly alter behaviors in a wide range of species, comparative studies that uniformly measure the impact of a single experience across multiple species have been lacking, limiting our understanding of how plastic traits evolve. To address this, we quantified variations in social feeding behaviors across 10 species of Drosophilids, tested the effect of altering rearing context on these behaviors (reared in groups or in isolation) and correlated observed behavioral shifts to accompanying transcriptional changes in the heads of these flies. We observed significant variability in the extent of aggressiveness, the utilization of social cues during food search, and social space preferences across species. The sensitivity of these behaviors to rearing experience also varied: socially naive flies were more aggressive than their socialized conspecifics in some species, and more reserved or identical in others. Despite these differences, the mechanism of socialization appeared to be conserved within the melanogaster subgroup as species could cross-socialize each other, and the transcriptional response to social exposure was significantly conserved. The expression levels of chemosensory-perception genes often varied between species and rearing conditions, supporting a growing body of evidence that behavioral evolution is driven by the differential regulation of this class of genes. The clear differences in behavioral responses to socialization observed in Drosophilids make this an ideal system for continued studies on the genetic basis and evolution of socialization and behavioral plasticity.


Assuntos
Drosophila/genética , Evolução Molecular , Comportamento Social , Transcriptoma , Animais , Drosophila/classificação , Drosophila/fisiologia , Comportamento Alimentar
15.
Cold Spring Harb Protoc ; 2018(11)2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30385668

RESUMO

The success of scientists in revealing biological mechanisms has depended in large part on choosing tractable model systems. In 1997, molecular phylogenetics revealed that two of biology's most tractable models-Caenorhabditis elegans and Drosophila-are much more closely related to each other than had been thought previously. I began to explore whether any of the little-studied members of this branch of the tree of life might serve as a new model for comparative biology that could make use of the rich and ongoing sources of information flowing from C. elegans and Drosophila research. Tardigrades, also known as water bears, make up a phylum of microscopic animals. The tardigrade Hypsibius exemplaris (recently disambiguated from a closely related species, Hypsibius dujardini) can be maintained in laboratories and has a generation time of <2 wk at room temperature. Stocks of animals can be stored frozen and revived. The animals and their embryos are optically clear, and embryos are laid in groups, with each synchronous clutch of embryos laid in a clear molt. We have developed techniques for laboratory study of this system, including methods for microinjection of animals, immunolocalization, in situ hybridization, RNA interference, transcriptomics, and methods for identifying proteins that mediate tolerance to extreme environments. Here, I review the development of this animal as an emerging model system, as well as recent molecular studies aimed at understanding the evolution of developmental mechanisms that underpin the evolution of animal form and at understanding how biological materials can survive extreme environments.


Assuntos
Caenorhabditis elegans/genética , Drosophila/genética , Embrião não Mamífero/metabolismo , Modelos Animais , Tardígrados/genética , Animais , Caenorhabditis elegans/classificação , Biologia do Desenvolvimento/métodos , Drosophila/classificação , Embrião não Mamífero/embriologia , Evolução Molecular , Estágios do Ciclo de Vida/genética , Filogenia , Tardígrados/classificação , Tardígrados/embriologia
16.
PLoS Genet ; 14(11): e1007770, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30388103

RESUMO

Y chromosomes are widely believed to evolve from a normal autosome through a process of massive gene loss (with preservation of some male genes), shaped by sex-antagonistic selection and complemented by occasional gains of male-related genes. The net result of these processes is a male-specialized chromosome. This might be expected to be an irreversible process, but it was found in 2005 that the Drosophila pseudoobscura Y chromosome was incorporated into an autosome. Y chromosome incorporations have important consequences: a formerly male-restricted chromosome reverts to autosomal inheritance, and the species may shift from an XY/XX to X0/XX sex-chromosome system. In order to assess the frequency and causes of this phenomenon we searched for Y chromosome incorporations in 400 species from Drosophila and related genera. We found one additional large scale event of Y chromosome incorporation, affecting the whole montium subgroup (40 species in our sample); overall 13% of the sampled species (52/400) have Y incorporations. While previous data indicated that after the Y incorporation the ancestral Y disappeared as a free chromosome, the much larger data set analyzed here indicates that a copy of the Y survived as a free chromosome both in montium and pseudoobscura species, and that the current Y of the pseudoobscura lineage results from a fusion between this free Y and the neoY. The 400 species sample also showed that the previously suggested causal connection between X-autosome fusions and Y incorporations is, at best, weak: the new case of Y incorporation (montium) does not have X-autosome fusion, whereas nine independent cases of X-autosome fusions were not followed by Y incorporations. Y incorporation is an underappreciated mechanism affecting Y chromosome evolution; our results show that at least in Drosophila it plays a relevant role and highlight the need of similar studies in other groups.


Assuntos
Drosophila/classificação , Drosophila/genética , Cromossomo Y/genética , Animais , Evolução Molecular , Feminino , Duplicação Gênica , Genes de Insetos , Ligação Genética , Masculino , Modelos Genéticos , Filogenia , Seleção Genética , Especificidade da Espécie , Translocação Genética , Cromossomo X/genética
17.
Sci Rep ; 8(1): 11839, 2018 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-30087364

RESUMO

Drosophila suzukii is an invasive fly of East Asian origin that has become a serious fruit pest worldwide. Classical biological control through the introduction of parasitoids from Asia could help reduce populations of D. suzukii in invaded regions. Little is known about the native parasitoids of the fly in Asia. Therefore, surveys for larval parasitoids of D. suzukii were carried out in China and Japan between 2015 and 2017. Parasitoids of D. suzukii and other fruit-inhabiting drosophilids (D. pulchrella and D. subpulchrella) that are probably attacked by the same parasitoid complex were found in four Chinese provinces and four Japanese prefectures. Larval parasitoids were obtained at most sites where D. suzukii was found, with parasitism varying from 0.0 to 75.6%. At least eight parasitoid species were reared. The most abundant and frequent parasitoids were the Figitidae Ganaspis cf. brasiliensis and Leptopilina japonica, but another Leptopilina species and at least five Braconidae species belonging to the genera Areotetes, Asobara and Tanycarpa were obtained in low numbers. Due to its likely restricted host range, the most promising parasitoid for biological control is Ganaspis cf. brasiliensis. However, its exact specificity and taxonomic status require future research.


Assuntos
Formigas/fisiologia , Drosophila/fisiologia , Frutas/parasitologia , Controle Biológico de Vetores/métodos , Vespas/fisiologia , Animais , China , Drosophila/classificação , Geografia , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Japão , Larva/fisiologia
18.
Genome Biol Evol ; 10(8): 2086-2101, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30010752

RESUMO

The genomes of species that are ecological specialists will likely contain signatures of genomic adaptation to their niche. However, distinguishing genes related to ecological specialism from other sources of selection and more random changes is a challenge. Here, we describe the genome of Drosophila montana, which is the most extremely cold-adapted Drosophila species known. We use branch tests to identify genes showing accelerated divergence in contrasts between cold- and warm-adapted species and identify about 250 genes that show differences, possibly driven by a lower synonymous substitution rate in cold-adapted species. We also look for evidence of accelerated divergence between D. montana and D. virilis, a previously sequenced relative, but do not find strong evidence for divergent selection on coding sequence variation. Divergent genes are involved in a variety of functions, including cuticular and olfactory processes. Finally, we also resequenced three populations of D. montana from across its ecological and geographic range. Outlier loci were more likely to be found on the X chromosome and there was a greater than expected overlap between population outliers and those genes implicated in cold adaptation between Drosophila species, implying some continuity of selective process at these different evolutionary scales.


Assuntos
Drosophila/classificação , Drosophila/genética , Aclimatação , Animais , Temperatura Baixa , Diapausa , Drosophila/fisiologia , Genoma de Inseto , Anotação de Sequência Molecular , Filogenia
19.
Genetics ; 209(4): 1319-1328, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29884746

RESUMO

There are essentially an infinite number of traits that could be measured on any organism, and almost all individual traits display genetic variation, yet substantial genetic variance in a large number of independent traits is not plausible under basic models of selection and mutation. One mechanism that may be invoked to explain the observed levels of genetic variance in individual traits is that pleiotropy results in fewer dimensions of phenotypic space with substantial genetic variance. Multivariate genetic analyses of small sets of functionally related traits have shown that standing genetic variance is often concentrated in relatively few dimensions. It is unknown if a similar concentration of genetic variance occurs at a phenome-wide scale when many traits of disparate function are considered, or if the genetic variance generated by new mutations is also unevenly distributed across phenotypic space. Here, we used a Bayesian sparse factor model to characterize the distribution of mutational variance of 3385 gene expression traits of Drosophila serrata after 27 generations of mutation accumulation, and found that 46% of the estimated mutational variance was concentrated in just 21 dimensions with significant mutational heritability. We show that the extent of concentration of mutational variance into such a small subspace has the potential to substantially bias the response to selection of these traits.


Assuntos
Proteínas de Drosophila/genética , Drosophila/genética , Perfilação da Expressão Gênica/métodos , Mutação , Característica Quantitativa Herdável , Animais , Teorema de Bayes , Drosophila/classificação , Feminino , Regulação da Expressão Gênica , Masculino , Modelos Genéticos , Análise Multivariada , Fenótipo , Seleção Genética
20.
Genetics ; 209(1): 1-25, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29716983

RESUMO

Understanding phylogenetic relationships among taxa is key to designing and implementing comparative analyses. The genus Drosophila, which contains over 1600 species, is one of the most important model systems in the biological sciences. For over a century, one species in this group, Drosophila melanogaster, has been key to studies of animal development and genetics, genome organization and evolution, and human disease. As whole-genome sequencing becomes more cost-effective, there is increasing interest in other members of this morphologically, ecologically, and behaviorally diverse genus. Phylogenetic relationships within Drosophila are complicated, and the goal of this paper is to provide a review of the recent taxonomic changes and phylogenetic relationships in this genus to aid in further comparative studies.


Assuntos
Drosophila/classificação , Drosophila/genética , Filogenia , Animais , Código de Barras de DNA Taxonômico , Evolução Molecular
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