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1.
Genome Biol Evol ; 13(11)2021 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-34694399

RESUMO

Adenosine Deaminases that Act on RNA (ADARs) are RNA editing enzymes that play a dynamic and nuanced role in regulating transcriptome and proteome diversity. This editing can be highly selective, affecting a specific site within a transcript, or nonselective, resulting in hyperediting. ADAR editing is important for regulating neural functions and autoimmunity, and has a key role in the innate immune response to viral infections, where editing can have a range of pro- or antiviral effects and can contribute to viral evolution. Here we examine the role of ADAR editing across a broad range of viral groups. We propose that the effect of ADAR editing on viral replication, whether pro- or antiviral, is better viewed as an axis rather than a binary, and that the specific position of a given virus on this axis is highly dependent on virus- and host-specific factors, and can change over the course of infection. However, more research needs to be devoted to understanding these dynamic factors and how they affect virus-ADAR interactions and viral evolution. Another area that warrants significant attention is the effect of virus-ADAR interactions on host-ADAR interactions, particularly in light of the crucial role of ADAR in regulating neural functions. Answering these questions will be essential to developing our understanding of the relationship between ADAR editing and viral infection. In turn, this will further our understanding of the effects of viruses such as SARS-CoV-2, as well as many others, and thereby influence our approach to treating these deadly diseases.


Assuntos
Adenosina Desaminase/metabolismo , Edição de RNA , Vírus de RNA/genética , Adenosina Desaminase/genética , Animais , Evolução Molecular , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade , Vírus de RNA/classificação , Vírus de RNA/fisiologia , RNA Viral/genética , RNA Viral/metabolismo , Replicação Viral/genética
2.
Adv Virus Res ; 107: 285-314, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32711732

RESUMO

Organisms clear infections by mounting an immune response that is normally turned off once the pathogens have been cleared. However, sometimes this immune response is not properly or timely arrested, resulting in the host damaging itself. This immune dysregulation may be referred to as immunopathology. While our knowledge of immune and metabolic pathways in insects, particularly in response to viral infections, is growing, little is known about the mechanisms that regulate this immune response and hence little is known about immunopathology in this important and diverse group of organisms. In this chapter we focus both on documenting the molecular mechanisms described involved in restoring immune homeostasis in insects after viral infections and on identifying potential mechanisms for future investigation. We argue that learning about the immunopathological consequences of an improperly regulated immune response in insects will benefit both insect and human health.


Assuntos
Homeostase , Insetos , Viroses , Animais , Interações Hospedeiro-Patógeno/imunologia , Insetos/virologia , Viroses/veterinária
3.
Bioessays ; 41(6): e1800239, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31106880

RESUMO

Previous studies of Zika virus (ZIKV) pathogenesis have focused primarily on virus-driven pathology and neurotoxicity, as well as host-related changes in cell proliferation, autophagy, immunity, and uterine function. It is now hypothesized that ZIKV pathogenesis arises instead as an (unintended) consequence of host innate immunity, specifically, as the side effect of an otherwise well-functioning machine. The hypothesis presented here suggests a new way of thinking about the role of host immune mechanisms in disease pathogenesis, focusing on dysregulation of post-transcriptional RNA editing as a candidate driver of a broad range of observed neurodevelopmental defects and neurodegenerative clinical symptoms in both infants and adults linked with ZIKV infections. The authors collect and synthesize existing evidence of ZIKV-mediated changes in the expression of adenosine deaminases acting on RNA (ADARs), known links between abnormal RNA editing and pathogenesis, as well as ideas for future research directions, including potential treatment strategies.


Assuntos
Síndrome de Guillain-Barré/patologia , Síndrome de Guillain-Barré/virologia , Edição de RNA , Infecção por Zika virus/patologia , Infecção por Zika virus/virologia , Zika virus/patogenicidade , Adenosina Desaminase/genética , Adulto , Biomarcadores , Feminino , Expressão Gênica , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade Inata , Lactente , Recém-Nascido , Microcefalia/virologia , Teste Pré-Natal não Invasivo , Gravidez , Proteínas de Ligação a RNA/genética
4.
J Racial Ethn Health Disparities ; 5(3): 495-503, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-28726082

RESUMO

Increasing the diversity of tomorrow's healthcare work force remains a challenge despite many thoughtful published reports and recommendations. As part of an effort to grow a more diverse pre-professional health population, we created an undergraduate minor, Health Disparities in Society, at the University of Florida. Most courses for the minor were identified from existing offerings, and we created only two new courses, an introduction course and a capstone service-learning course. The new minor quickly became the most popular in the College of Liberal Arts and Sciences (which has approximately 12,000 total undergraduate students), and importantly, students selecting the minor were more likely to be under-represented minorities than would be expected given undergraduate demographics. Pre-professional students choosing this minor reflect the desired diversity of the healthcare workforce of tomorrow.


Assuntos
Currículo , Educação Pré-Médica , Disparidades nos Níveis de Saúde , Disparidades em Assistência à Saúde , Universidades , Negro ou Afro-Americano , Asiático , Diversidade Cultural , Educação , Feminino , Mão de Obra em Saúde , Hispânico ou Latino , Humanos , Masculino , Estados Unidos , População Branca
5.
Ecol Evol ; 7(15): 5967-5976, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28808558

RESUMO

Parasites are known to profoundly affect resource allocation in their host. In order to investigate the effects of Cryphonectria Hypovirus 1 (CHV1) on the life-history traits of its fungal host Cryphonectria parasitica, an infection matrix was completed with the cross-infection of six fungal isolates by six different viruses. Mycelial growth, asexual sporulation, and spore size were measured in the 36 combinations, for which horizontal and vertical transmission of the viruses was also assessed. As expected by life-history theory, a significant negative correlation was found between host somatic growth and asexual reproduction in virus-free isolates. Interestingly this trade-off was found to be positive in infected isolates, illustrating the profound changes in host resource allocation induced by CHV1 infection. A significant and positive relationship was also found in infected isolates between vertical transmission and somatic growth. This last relationship suggests that in this system, high levels of virulence could be detrimental to the vertical transmission of the parasite. Those results underscore the interest of studying host-parasite interaction within the life-history theory framework, which might permit a more accurate understanding of the nature of the modifications triggered by parasite infection on host biology.

6.
Ecol Evol ; 7(12): 4475-4485, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28649357

RESUMO

Zika virus (ZIKV) is a mosquito-transmitted flavivirus, linked to microcephaly and fetal death in humans. Here, we investigate whether host-mediated RNA editing of adenosines (ADAR) plays a role in the molecular evolution of ZIKV. Using complete coding sequences for the ZIKV polyprotein, we show that potential ADAR substitutions are underrepresented at the ADAR-resistant GA dinucleotides of both the positive and negative strands, that these changes are spatially and temporally clustered (as expected of ADAR editing) for three branches of the viral phylogeny, and that ADAR mutagenesis can be linked to its codon usage. Furthermore, resistant GA dinucleotides are enriched on the positive (but not negative) strand, indicating that the former is under stronger purifying selection than the latter. ADAR editing also affects the evolution of the rhabdovirus sigma. Our study now documents that host ADAR editing is a mutation and evolutionary force of positive- as well as negative-strand RNA viruses.

7.
Genome Biol Evol ; 8(9): 2952-2963, 2016 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-27614234

RESUMO

Sigma virus (DMelSV) is ubiquitous in natural populations of Drosophila melanogaster. Host-mediated, selective RNA editing of adenosines to inosines (ADAR) may contribute to control of viral infection by preventing transcripts from being transported into the cytoplasm or being translated accurately; or by increasing the viral genomic mutation rate. Previous PCR-based studies showed that ADAR mutations occur in DMelSV at low frequency. Here we use SOLiDTM deep sequencing of flies from a single host population from Athens, GA, USA to comprehensively evaluate patterns of sequence variation in DMelSV with respect to ADAR. GA dinucleotides, which are weak targets of ADAR, are strongly overrepresented in the positive strand of the virus, consistent with selection to generate ADAR resistance on this complement of the transient, double-stranded RNA intermediate in replication and transcription. Potential ADAR sites in a worldwide sample of viruses are more likely to be "resistant" if the sites do not vary among samples. Either variable sites are less constrained and hence are subject to weaker selection than conserved sites, or the variation is driven by ADAR. We also find evidence of mutations segregating within hosts, hereafter referred to as hypervariable sites. Some of these sites were variable only in one or two flies (i.e., rare); others were shared by four or even all five of the flies (i.e., common). Rare and common hypervariable sites were indistinguishable with respect to susceptibility to ADAR; however, polymorphism in rare sites were more likely to be consistent with the action of ADAR than in common ones, again suggesting that ADAR is deleterious to the virus. Thus, in DMelSV, host mutagenesis is constraining viral evolution both within and between hosts.


Assuntos
Drosophila melanogaster/virologia , Genoma Viral , Vírus de Insetos/genética , Taxa de Mutação , Rhabdoviridae/genética , Adenosina/genética , Animais , Interações Hospedeiro-Patógeno , Inosina/genética , Mutagênese , Polimorfismo Genético , Edição de RNA
8.
Genome Biol Evol ; 6(4): 818-29, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24696400

RESUMO

The mechanistic basis of regulatory variation and the prevailing evolutionary forces shaping that variation are known to differ between sexes and between chromosomes. Regulatory variation of gene expression can be due to functional changes within a gene itself (cis) or in other genes elsewhere in the genome (trans). The evolutionary properties of cis mutations are expected to differ from mutations affecting gene expression in trans. We analyze allele-specific expression across a set of X substitution lines in intact adult Drosophila simulans to evaluate whether regulatory variation differs for cis and trans, for males and females, and for X-linked and autosomal genes. Regulatory variation is common (56% of genes), and patterns of variation within D. simulans are consistent with previous observations in Drosophila that there is more cis than trans variation within species (47% vs. 25%, respectively). The relationship between sex-bias and sex-limited variation is remarkably consistent across sexes. However, there are differences between cis and trans effects: cis variants show evidence of purifying selection in the sex toward which expression is biased, while trans variants do not. For female-biased genes, the X is depleted for trans variation in a manner consistent with a female-dominated selection regime on the X. Surprisingly, there is no evidence for depletion of trans variation for male-biased genes on X. This is evidence for regulatory feminization of the X, trans-acting factors controlling male-biased genes are more likely to be found on the autosomes than those controlling female-biased genes.


Assuntos
Alelos , Cromossomos de Insetos/genética , Drosophila/genética , Regulação da Expressão Gênica , Caracteres Sexuais , Cromossomo X/genética , Animais , Feminino , Masculino
9.
10.
Genome Biol Evol ; 5(1): 1-15, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23193178

RESUMO

We explore the evolutionary origins of dosage compensation (DC) in sex chromosomes in the context of metabolic control theory. We consider first the cost of gene loss (hemizygosity) per se in reducing flux, and examine two relationships between flux and fitness (linear and Gaussian) to calculate a fitness cost of hemizygosity. Recognizing that new sex chromosomes are derived from autosomes, we also calculate the cost of unmasking deleterious mutations segregating on the nascent sex chromosomes as loci become hemizygous. The importance of deleterious mutations to the fitness cost of hemizygosity depends on their frequency, and on the relative costs of halving gene dose for wild-type alleles. We then consider the evolution of DC in response to gene loss, and include a cost of overexpression (i.e., DC such that expression exceeds the wild-type homozygote). Even with costs to excess flux, hypomorphic mutations can cause the optimal level of DC to be higher than 2-fold when the absolute cost of hemizygosity is small. Finally, we propose a three-step model of DC evolution: 1) once recombination ceases and the Y begins to deteriorate, genes from longer metabolic pathways should be lost first, as halving these genes does not drastically reduce flux or, thereby, fitness; 2) both the cost of hemizygosity and the presence of hypomorphic mutations will drive an increase in expression, that is, DC; 3) existing DC will now permit loss of genes in short pathways.


Assuntos
Mecanismo Genético de Compensação de Dose , Hemizigoto , Mutação , Animais , Evolução Molecular , Frequência do Gene , Genes , Aptidão Genética , Redes e Vias Metabólicas/genética , Modelos Genéticos , Modelos Teóricos , Recombinação Genética , Cromossomo X/genética , Cromossomo Y/genética
11.
Behav Ecol Sociobiol ; 67(4): 529-540, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27616808

RESUMO

The risk of disease transmission can affect female mating rate, and thus sexual conflict. Furthermore, the interests of a sexually transmitted organism may align or diverge with those of either sex, potentially making the disease agent a third participant in the sexual arms race. In Drosophila melanogaster, where sexual conflict over female mating rate is well established, we investigated how a common, non-lethal virus (sigma virus) might affect this conflict. We gave uninfected females the opportunity to copulate twice in no-choice trials: either with two uninfected males, or with one male infected with sigma virus followed by an uninfected male. We assessed whether females respond behaviorally to male infection, determined whether male infection affects either female or male reproductive success, and measured offspring infection rates. Male infection status did not influence time to copulation, or time to re-mating. However, male infection did affect male reproductive success: first males sired a significantly greater proportion of offspring, as well as more total offspring, when they were infected with sigma virus. Thus viral infection may provide males an advantage in sperm competition, or, possibly, females may preferentially use infected sperm. We found no clear costs of infection in terms of offspring survival. Viral reproductive success (the number of infected offspring) was strongly correlated with male reproductive success. Further studies are needed to demonstrate whether virus-induced changes in reproductive success affect male and female lifetime fitness, and whether virus-induced changes are under male, female, or viral control.

13.
G3 (Bethesda) ; 1(6): 427-36, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22384353

RESUMO

Multilevel analysis of transcription is facilitated by a new array design that includes modules for assessment of differential expression, isoform usage, and allelic imbalance in Drosophila. The ∼2.5 million feature chip incorporates a large number of controls, and it contains 18,769 3' expression probe sets and 61,919 exon probe sets with probe sequences from Drosophila melanogaster and 60,118 SNP probe sets focused on Drosophila simulans. An experiment in D. simulans identified genes differentially expressed between males and females (34% in the 3' expression module; 32% in the exon module). These proportions are consistent with previous reports, and there was good agreement (κ = 0.63) between the modules. Alternative isoform usage between the sexes was identified for 164 genes. The SNP module was verified with resequencing data. Concordance between resequencing and the chip design was greater than 99%. The design also proved apt in separating alleles based upon hybridization intensity. Concordance between the highest hybridization signals and the expected alleles in the genotype was greater than 96%. Intriguingly, allelic imbalance was detected for 37% of 6579 probe sets examined that contained heterozygous SNP loci. The large number of probes and multiple probe sets per gene in the 3' expression and exon modules allows the array to be used in D. melanogaster and in closely related species. The SNP module can be used for allele specific expression and genotyping of D. simulans.

14.
Evol Ecol Res ; 13: 323-345, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-28217032

RESUMO

QUESTION: How do vertically transmitted parasites persist? ORGANISMS: Drosophila melanogaster (host) and sigma virus (parasite). FIELD SITE: Peach stands in northern Georgia, USA, on a transect between Macon and Athens. EMPIRICAL METHODS: We estimated prevalence in the field. We also estimated male and female transmission in the laboratory, using field-collected animals as parents. We further quantified patrilineal (father to son) transmission in the laboratory, and estimated cost of infection (virulence) by quantifying decreased egg production of infected flies. MATHEMATICAL METHODS: Discrete-time, deterministic models for prevalence; analysis of stability of disease-free and endemic equilibria; numerical computation of equilibria based on empirical estimates. KEY ASSUMPTIONS: Random mating, discrete generations, cost of infection to females only. PREDICTIONS AND CONCLUSIONS: The model allows persistence under parameter estimates obtained for this population. Uncertainty in parameters leads to wide confidence intervals on the predicted prevalence, which may be systematically underestimated due to Jensen's inequality. Male transmission is required for persistence, and multiple generations of strictly patrilineal transmission are possible in the laboratory, albeit with decreasing transmission efficiency.

15.
Evolution ; 65(4): 1068-78, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21108635

RESUMO

Genes involved in host-pathogen interactions are expected to be evolving under complex coevolutionary dynamics, including positive directional and/or frequency-dependent selection. Empirical work has largely focused on the evolution of immune genes at the level of the protein sequence. We examine components of genetic variance for transcript abundance of defense genes in Drosophila melanogaster and D. simulans using a diallel and a round robin breeding design, respectively, and infer modes of evolution from patterns of segregating genetic variation. Defense genes in D. melanogaster are overrepresented relative to nondefense genes among genes with evidence of significant additive variance for expression. Directional selection is expected to deplete additive genetic variance, whereas frequency-dependent selection is expected to maintain additive variance. However, relaxed selection (reduced or no purifying selection) is an alternative interpretation of significant additive variation. Of the three classes of defense genes, the recognition and effector classes show an excess of genes with significant additive variance; whereas signaling genes, in contrast, are overrepresented for dominance variance. Analysis of protein-coding sequences revealed no evidence for an association between additive or dominance variation in expression and directional selection. Both balancing selection driven by host-pathogen coevolution and relaxed selection for expression of uninduced defense genes are viable interpretations of these data.


Assuntos
Drosophila/genética , Evolução Molecular , Regulação da Expressão Gênica/genética , Genes de Insetos/genética , Interações Hospedeiro-Patógeno/genética , Imunidade Inata/genética , Seleção Genética , Animais , California , Biologia Computacional , Cruzamentos Genéticos , Drosophila/metabolismo , Perfilação da Expressão Gênica , Modelos Lineares , Especificidade da Espécie
16.
Genetics ; 183(2): 547-61, 1SI-21SI, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19667135

RESUMO

Species-specific regulation of gene expression contributes to the development and maintenance of reproductive isolation and to species differences in ecologically important traits. A better understanding of the evolutionary forces that shape regulatory variation and divergence can be developed by comparing expression differences among species and interspecific hybrids. Once expression differences are identified, the underlying genetics of regulatory variation or divergence can be explored. With the goal of associating cis and/or trans components of regulatory divergence with differences in gene expression, overall and allele-specific expression levels were assayed genomewide in female adult heads of Drosophila melanogaster, D. simulans, and their F1 hybrids. A greater proportion of cis differences than trans differences were identified for genes expressed in heads and, in accordance with previous studies, cis differences also explained a larger number of species differences in overall expression level. Regulatory divergence was found to be prevalent among genes associated with defense, olfaction, and among genes downstream of the Drosophila sex determination hierarchy. In addition, two genes, with critical roles in sex determination and micro RNA processing, Sxl and loqs, were identified as misexpressed in hybrid female heads, potentially contributing to hybrid incompatibility.


Assuntos
Drosophila melanogaster/genética , Drosophila/genética , Genoma de Inseto/genética , Estudo de Associação Genômica Ampla/métodos , Alelos , Animais , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Cruzamentos Genéticos , Drosophila/crescimento & desenvolvimento , Drosophila melanogaster/crescimento & desenvolvimento , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Genes de Insetos/genética , Variação Genética , Hibridização Genética , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Especificidade da Espécie
17.
BMC Genomics ; 10: 124, 2009 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-19317915

RESUMO

BACKGROUND: A molecular process based genotype-to-phenotype map will ultimately enable us to predict how genetic variation among individuals results in phenotypic alterations. Building such a map is, however, far from straightforward. It requires understanding how molecular variation re-shapes developmental and metabolic networks, and how the functional state of these networks modifies phenotypes in genotype specific way. We focus on the latter problem by describing genetic variation in transcript levels of genes in the InR/TOR pathway among 72 Drosophila melanogaster genotypes. RESULTS: We observe tight co-variance in transcript levels of genes not known to influence each other through direct transcriptional control. We summarize transcriptome variation with factor analyses, and observe strong co-variance of gene expression within the dFOXO-branch and within the TOR-branch of the pathway. Finally, we investigate whether major axes of transcriptome variation shape phenotypes expected to be influenced through the InR/TOR pathway. We find limited evidence that transcript levels of individual upstream genes in the InR/TOR pathway predict fly phenotypes in expected ways. However, there is no evidence that these effects are mediated through the major axes of downstream transcriptome variation. CONCLUSION: In summary, our results question the assertion of the 'sparse' nature of genetic networks, while validating and extending candidate gene approaches in the analyses of complex traits.


Assuntos
Drosophila melanogaster/genética , Redes Reguladoras de Genes , Insulina/genética , Animais , Proteínas de Drosophila/genética , Feminino , Fatores de Transcrição Forkhead/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Genes de Insetos , Variação Genética , Genoma de Inseto , Masculino , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Receptores Proteína Tirosina Quinases/genética
18.
Genetics ; 181(2): 421-34, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19015538

RESUMO

Many genes in eukaryotic genomes produce multiple transcripts through a variety of molecular mechanisms including alternative splicing. Alternatively spliced transcripts often encode functionally distinct proteins, indicating that gene regulation at this level makes an important contribution to organismal complexity. The multilevel splicing cascade that regulates sex determination and sex-specific development in Drosophila is a classical example of the role of alternative splicing in cell differentiation. Recent evidence suggests that a large proportion of genes in the Drosophila genome may be spliced in a sex-biased fashion, raising the possibility that alternative splicing may play a more general role in sexually dimorphic development and physiology. However, the prevalence of sex-specific splicing and the extent to which it is shared among genotypes are not fully understood. Genetic variation in the splicing of key components of the sex determination pathway is known to influence the expression of downstream target genes, suggesting that alternative splicing at other loci may also vary in functionally important ways. In this study, we used exon-specific microarrays to examine 417 multitranscript genes for evidence of sex-specific and genotype-specific splicing in 80 different genotypes of Drosophila melanogaster. Most of these loci showed sex-biased splicing, whereas genotype-specific splicing was rare. One hundred thirty-five genes showed different alternative transcript use in males vs. females. Real-time PCR analysis of 6 genes chosen to represent a broad range of biological functions showed that most sex-biased splicing occurs in the gonads. However, somatic tissues, particularly adult heads, also show evidence of sex-specific splicing. Comparison of splicing patterns at orthologous loci in seven Drosophila species shows that sexual biases in alternative exon representation are highly conserved, indicating that sex-specific splicing is an ancient feature of Drosophila biology. To investigate potential mechanisms of sex-biased splicing, we used real-time PCR to examine the expression of six known regulators of alternative splicing in males vs. females. We found that all six loci are themselves spliced sex specifically in gonads and heads, suggesting that regulatory hierarchies based on alternative splicing may be an important feature of sexual differentiation.


Assuntos
Processamento Alternativo , Drosophila melanogaster/genética , Caracteres Sexuais , Animais , Cruzamentos Genéticos , Drosophila/classificação , Drosophila/genética , Evolução Molecular , Éxons , Feminino , Genes de Insetos , Genótipo , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Especificidade da Espécie , Distribuição Tecidual
19.
Genetica ; 135(3): 289-98, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18500651

RESUMO

In order to examine the genetic relationships among life-history traits in a hermaphroditic species we used artificial selection for increased egg size and measured correlated responses across the life cycle of the serpulid polychaete Hydroides elegans, a protandrous sequential hermaphrodite. We recorded sex ratios across generations, and measured egg size, egg energy, larval volume at two time points, juvenile tube length, adult dry weight and fecundity after selection. Selection for larger eggs produced positive correlated responses in egg energy, fecundity and larval size at competence. Selection for increased egg size was also manifested by earlier sex change and this resulted in selected individuals spending less time as males relative to controls. We propose that egg size is negatively correlated with duration of andromorphy, that is, that female fitness trades off with male fitness.


Assuntos
Óvulo/crescimento & desenvolvimento , Poliquetos/crescimento & desenvolvimento , Análise de Variância , Animais , Evolução Molecular , Feminino , Fertilidade , Estágios do Ciclo de Vida/fisiologia , Masculino , Fenótipo , Poliquetos/genética , Poliquetos/fisiologia
20.
Mol Biol Evol ; 25(1): 101-10, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17998255

RESUMO

The dissection of intraspecific variation in transcriptome is a central theme of many recent quantitative genomic analyses. Transcript level variation has been attributed to factors at the gene itself (cis) and elsewhere in the genome (trans). Previous analyses of Drosophila intraspecific transcriptome variation pointed toward a larger contribution of trans factors. However, data from other genera, and from interspecific comparisons within Drosophila, are more consistent with a major role for cis factors. We investigated the relative amount of cis and trans variation in Drosophila melanogaster, using whole-genome expression from an oligonucleotide microarray in the 2 extensively studied genotypes Ore and 2b3, and 6 recombinant inbred (RI) lines derived from these parents. We examined 2 types of models to decompose cis and trans contributions to genetic variation in transcript level: 1) an infinitesimal model assuming that the transcription variation is highly polygenic and due to many small effects and 2) contrast models assuming that a few large effects contribute to the transcriptional variation. We explicitly fitted cis-by-trans interactions and extended our analyses to consider regulation of alternatively spliced transcripts. We estimated that approximately 10% of the transcriptome was differentially regulated among the lines. We were able to identify cis and trans effects that contribute to this differential regulation for 1,340 genes. Our analyses revealed numerous cis effects (90%) but much fewer trans effects, perhaps due to reduced power of detection for trans effects. In addition, we identified 15 genes that have alternative splice variants differentially regulated in cis.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Genes de Insetos/genética , Modelos Genéticos , Fatores de Transcrição/genética , Transcrição Gênica/genética , Processamento Alternativo/genética , Animais , Especificidade da Espécie
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