56 research outputs found
Effet de la polyploïdisation sur le complexe méthylome-transcriptome chez le blé
No full textAllopolyploidization, involving the combination of distinct genomes followed by whole-genome duplication, is a widespread phenomenon in plants, including wheat. Bread wheat (Triticum aestivum L., AABBDD) has a complex hexaploid genome shaped by the hybridization between tetraploid wheat (T. turgidum, AABB) and diploid goatgrass (Aegilops tauschii, DD) around 10 000 years ago. This phenomenon can be recreated in nascent polyploids, providing an opportunity to study its immediate effects on the genome (transcriptome and epigenome) reprogramming.This thesis takes advantage of synthetic hexaploid wheats produced in the GDEC unit, including genotypes from distinct parental combinations, reciprocal crosses, successive generations, and nucleic acid samples taken from leaf and grain tissues. The transcriptomic analysis revealed limited alterations of gene expression (around 1% of the total analyzed) in response to polyploidization. While these differentially expressed genes (DEGs) can be reproducible across various cross combinations and heritable through successive generations, they are not shared among tissues. Similarly, DNA methylation around transcription start sites (TSS) showed extremely few alterations (~0.2% of the total analyzed genes) and was not statistically associated with expression changes triggered by polyploidization. Although distinct patterns of methylation according to gene expression status were observed when averaging TSS methylation across all genes at 10 bp resolution, the high variability of methylation levels within each expression group, and the overall weak correlation between methylation and expression do not support a direct relationship, but rather suggest a multidirectional or complex association. Additional investigations of possible causes of transcriptional changes after polyploidization included PCR-based screening of 77 downregulated genes. Homeolog specific PCRs detected no deletion event for 76 genes in the hexaploid synthetics, indicating that the downregulation signals are typically caused by silencing rather than losses. Subsequent amplicon-based investigation of DNA methylation including various partitions of these genes (e.g., exons, introns, 3′ UTRs) did not reveal an association with the downregulation signal, however, a more comprehensive analysis would be required to make a definitive conclusion.Overall, this analysis demonstrates that polyploidization induces minor changes in both the transcriptome and DNA methylation, which may be comparable to those observed in intraspecific hybridization between. Moreover, it suggests that the relationship between DNA methylation and gene expression is more complex than a straightforward link, yet remains intriguing and deserves deeper investigations.L'allopolyploïdisation, impliquant la combinaison de génomes distincts suivie d'une duplication du génome entier, est un phénomène répandu chez les plantes, dont le blé. Le blé tendre (Triticum aestivum L., AABBDD) possède un génome hexaploïde complexe, issu de l'hybridation entre le blé tétraploïde (T. turgidum, AABB) et diploïde (Aegilops tauschii, DD) il y a environ 10 000 ans. Ce phénomène peut être reproduit chez les polyploïdes synthétiques, offrant ainsi l'opportunité d'étudier ses effets immédiats sur la reprogrammation du génome (transcriptome et épigénome).Cette thèse s'appuie sur des blés hexaploïdes synthétiques produits dans l'unité GDEC, incluant des génotypes issus de combinaisons parentales distinctes, de croisements réciproques, de générations successives et d'échantillons prélevés sur des tissus foliaires et de grains. L'analyse transcriptomique a révélé des altérations limitées de l'expression génique (environ1 % du total analysé) en réponse à la polyploïdisation. Bien que ces gènes différentiellement exprimés (DEG) puissent être reproductibles à travers diverses combinaisons de croisements et transmissibles de génération en génération, ils ne sont pas partagés entre les tissus. De même, la méthylation de l'ADN autour des sites d'initiation de la transcription (TSS) a montré extrêmement peu d'altérations (~0,2 % du total des gènes analysés) et n'était pas statistiquement associée aux changements d'expression déclenchés par la polyploïdisation. Bien que des profils de méthylation distincts selon leur expression génique aient été observés en considérant la moyenne de la méthylation des TSS sur tous les gènes à une résolution de 10 pb, la forte variabilité des niveaux de méthylation au sein de chaque profil d'expression et la faible corrélation globale entre méthylation et expression ne corroborent pas une relation directe, mais suggèrent plutôt une association multidirectionnelle ou complexe entre expression et méthylation à l'échelle du génome. De plus, le criblage par PCR (spécifique aux homeologues) de 77 gènes sous-exprimés après polyploïdisation a confirmé l'absence de délétion pour 76 gènes chez les gènes synthétiques hexaploïdes, indiquant que ces gènes sont plutôt inhibés que délétés. L'étude de la méthylation de l'ADN, basée sur des amplicons portant sur diverses parties de ces gènes (exons, introns, 3′ UTR), n'a pas révélé d'association avec le signal de sous-expression ; toutefois, une analyse plus complète serait nécessaire pour parvenir à une conclusion définitive.Globalement, cette analyse démontre que la polyploïdisation induit des modifications mineures du transcriptome et de la méthylation de l'ADN, comparables à celles observées lors d'une hybridation intraspécifique. De plus, elle suggère que la relation entre la méthylation de l'ADN et l'expression génique est plus complexe qu'un simple lien, mais demeure intrigante et mérite des recherches plus approfondies
Effet de la polyploïdisation sur le complexe méthylome-transcriptome chez le blé
No full textAllopolyploidization, involving the combination of distinct genomes followed by whole-genome duplication, is a widespread phenomenon in plants, including wheat. Bread wheat (Triticum aestivum L., AABBDD) has a complex hexaploid genome shaped by the hybridization between tetraploid wheat (T. turgidum, AABB) and diploid goatgrass (Aegilops tauschii, DD) around 10 000 years ago. This phenomenon can be recreated in nascent polyploids, providing an opportunity to study its immediate effects on the genome (transcriptome and epigenome) reprogramming.This thesis takes advantage of synthetic hexaploid wheats produced in the GDEC unit, including genotypes from distinct parental combinations, reciprocal crosses, successive generations, and nucleic acid samples taken from leaf and grain tissues. The transcriptomic analysis revealed limited alterations of gene expression (around 1% of the total analyzed) in response to polyploidization. While these differentially expressed genes (DEGs) can be reproducible across various cross combinations and heritable through successive generations, they are not shared among tissues. Similarly, DNA methylation around transcription start sites (TSS) showed extremely few alterations (~0.2% of the total analyzed genes) and was not statistically associated with expression changes triggered by polyploidization. Although distinct patterns of methylation according to gene expression status were observed when averaging TSS methylation across all genes at 10 bp resolution, the high variability of methylation levels within each expression group, and the overall weak correlation between methylation and expression do not support a direct relationship, but rather suggest a multidirectional or complex association. Additional investigations of possible causes of transcriptional changes after polyploidization included PCR-based screening of 77 downregulated genes. Homeolog specific PCRs detected no deletion event for 76 genes in the hexaploid synthetics, indicating that the downregulation signals are typically caused by silencing rather than losses. Subsequent amplicon-based investigation of DNA methylation including various partitions of these genes (e.g., exons, introns, 3′ UTRs) did not reveal an association with the downregulation signal, however, a more comprehensive analysis would be required to make a definitive conclusion.Overall, this analysis demonstrates that polyploidization induces minor changes in both the transcriptome and DNA methylation, which may be comparable to those observed in intraspecific hybridization between. Moreover, it suggests that the relationship between DNA methylation and gene expression is more complex than a straightforward link, yet remains intriguing and deserves deeper investigations.L'allopolyploïdisation, impliquant la combinaison de génomes distincts suivie d'une duplication du génome entier, est un phénomène répandu chez les plantes, dont le blé. Le blé tendre (Triticum aestivum L., AABBDD) possède un génome hexaploïde complexe, issu de l'hybridation entre le blé tétraploïde (T. turgidum, AABB) et diploïde (Aegilops tauschii, DD) il y a environ 10 000 ans. Ce phénomène peut être reproduit chez les polyploïdes synthétiques, offrant ainsi l'opportunité d'étudier ses effets immédiats sur la reprogrammation du génome (transcriptome et épigénome).Cette thèse s'appuie sur des blés hexaploïdes synthétiques produits dans l'unité GDEC, incluant des génotypes issus de combinaisons parentales distinctes, de croisements réciproques, de générations successives et d'échantillons prélevés sur des tissus foliaires et de grains. L'analyse transcriptomique a révélé des altérations limitées de l'expression génique (environ1 % du total analysé) en réponse à la polyploïdisation. Bien que ces gènes différentiellement exprimés (DEG) puissent être reproductibles à travers diverses combinaisons de croisements et transmissibles de génération en génération, ils ne sont pas partagés entre les tissus. De même, la méthylation de l'ADN autour des sites d'initiation de la transcription (TSS) a montré extrêmement peu d'altérations (~0,2 % du total des gènes analysés) et n'était pas statistiquement associée aux changements d'expression déclenchés par la polyploïdisation. Bien que des profils de méthylation distincts selon leur expression génique aient été observés en considérant la moyenne de la méthylation des TSS sur tous les gènes à une résolution de 10 pb, la forte variabilité des niveaux de méthylation au sein de chaque profil d'expression et la faible corrélation globale entre méthylation et expression ne corroborent pas une relation directe, mais suggèrent plutôt une association multidirectionnelle ou complexe entre expression et méthylation à l'échelle du génome. De plus, le criblage par PCR (spécifique aux homeologues) de 77 gènes sous-exprimés après polyploïdisation a confirmé l'absence de délétion pour 76 gènes chez les gènes synthétiques hexaploïdes, indiquant que ces gènes sont plutôt inhibés que délétés. L'étude de la méthylation de l'ADN, basée sur des amplicons portant sur diverses parties de ces gènes (exons, introns, 3′ UTR), n'a pas révélé d'association avec le signal de sous-expression ; toutefois, une analyse plus complète serait nécessaire pour parvenir à une conclusion définitive.Globalement, cette analyse démontre que la polyploïdisation induit des modifications mineures du transcriptome et de la méthylation de l'ADN, comparables à celles observées lors d'une hybridation intraspécifique. De plus, elle suggère que la relation entre la méthylation de l'ADN et l'expression génique est plus complexe qu'un simple lien, mais demeure intrigante et mérite des recherches plus approfondies
Is transcriptional reprogramming following wheat polyploidization driven by DNA methylation changes?
No full textInternational audienceBread wheat is a natural allohexaploid that can be recreated artificially, producing 'synthetic' wheat with significant use in breeding programs. The hybridization between diploid Aegilops tauschii and tetraploid durum wheat (the first step in wheat allohexaploidization) can cause transcriptional activation of some transposable element (TE) families and heritable transcriptional reprogramming of a subset of genes. Although we have recently demonstrated that such changes are much less frequent than previously thought, questions remain about the mechanism of their establishment. It has been hypothesized that DNA methylation changes could be responsible for the remodelling of the transcriptome. The changes could arise during the development of hybrid embryos, as a result of imbalanced parental genome doses. It has been proposed that endosperm-derived siRNAs could migrate to the embryo and guide de novo methylation of previously unmethylated targets, analogically to the reinforcement of TE methylation observed during gametogenesis. Here we examine whether genes differentially expressed (DEGs) between a synthetic wheat allohexaploid and its parents also differ in DNA methylation levels around their transcription start sites, using capture-bisulfate sequencing datasets. We also search for a connection between siRNAs and DEGs, and more generally, investigate the temporal dynamics of TEs and siRNAs during grain development in wheat. We found little evidence in support of the hypothesized involvement of DNA methylation in the transcriptional reprogramming of nascent wheat polyploids
The mirage of DNA methylation in transcriptional regulation of plants
No full text'Cytosine methylation plays an important role in the regulation of gene expression in plants.' Some iteration of this statement can be found in most papers centered on plant epigenetics, and has become a widely accepted textbook claim. However, our generalized understanding of how DNA methylation exerts control over transcription is now challenged by observations demonstrating that transcriptional levels of most genes are unresponsive to DNA methylation changes. On a genome-wide scale, associations between DNA methylation and transcription are usually statistically weak. Even when correlations are found, the cause and effect can be difficult to identify, as methylation changes sometimes follow rather than precede transcriptional changes. While a growing number of studies explores a possible connection between differentially expressed genes (DEGs) and differentially methylated genes (DMGs), we demonstrate here that DEG-DMG overlaps are often significantly smaller than what could be expected by chance. This indicates that, contrary to expectations, changes in DNA methylation and changes in transcription sometimes avoid one another. Here, we discuss such observations and their implications for the hypothesis of a widespread control of gene expression by DNA methylation. While there are well-documented examples where DNA methylation regulates transcription, we argue that such cases represent a minority of genes, and we opine that approaches of reverse epigenetics are therefore unlikely to find broad application in breeding
LE ROI DE KAHEL ET LE TERRORISTE NOIR DE MONENEMBO: UNE REECRITURE POSTCOLONIALE DE L’HISTOIRE
No full textThe historical evolution of the African continent was not smooth; the region experienced many upheavals including two powerful traumas that are slavery and colonialism. It is therefore not surprising that African writers, who are mainly inspired by the world around them, revisit History to write their novels. Among them, the Guinean writer Tierno Monénembo. The writer sheds the light on the history that has painfully shaken his continent, West Africa more precisely. His novels translate the almost obsessive concern to narrate the story of the African continent. We propose to study two of his novels: The king of Kahel (2008) and The black terrorist (2012). In these novels, the author offers a different reading of colonial memory, moving away from the long-standing Manichaeism between white and black. Through the romanticized biography of Viscount Sanderval - driven by a sincere desire to civilize the negroes but at the same time to conquer a kingdom in the region of Fouta-Djalon-, or that of Addi Bâ, a young Senegalese gunner who will enter, during the Second World War, in France, the reader is invited to dive into a troubled past and discover all the complexity of Franco-African politics. Our purpose is to show the way History fits in the novels of Monénembo, by studying literary devices in the novels as well as the representation of two historical figures: Sanderval and Addi Bâ
DNA methylation around transcription start sites not globally associated with transcription in the grain of natural and synthetic hexaploid wheat
No full textEpigenetic mechanisms including DNA methylation are assumed to play crucial roles in the maintenance of genome integrity, regulation of gene expression and development, and their increasing exploitation in breeding applications is anticipated. However, the relationship between DNA methylation and gene expression remains ambiguous and difficult to generalize. Here we explored the hypothesized causality between the level of transcription and cytosine methylation at the 5' end of genes (around transcription start sites and start codons) in relation to whole-genome duplication in natural and synthetic allohexaploid wheat (Triticum/Aegilops complex). Using transcriptomes and a sequence capture protocol coupled with bisulfite sequencing, we observed sometimes significant, but overall very weak associations between gene expression and 5' end methylation on a genome-wide scale. In synthetic wheat allohexaploids, global methylation differences between subgenomes are not triggered by the polyploidization, as the subgenome patterns are rather faithfully inherited from parents. A small number of genes differentially methylated between the parents and synthetics was consistently recovered in reciprocal synthetics and subsequent generations. Differences in transcription between homeologs are not clearly associated with 5' end methylation in either natural or synthetic wheat. Overall, allopolyploidization triggers only minor methylation changes around transcription start sites and start codons of nascent wheat allopolyploids, and these are not statistically associated with differential expression. Although there is a measurable methylation difference between expressed and non-expressed genes, our results do not support the hypothesis that 5' end DNA methylation is engaged in the regulation of gene expression in natural and synthetic wheat
Style in Translation A Comparative Stylistic Analysis of The Sand Child by Tahar Ben Jelloun
No full textRecently, Theorists began to think that studying language linguistically is insufficiently beneficial, literary critics also believed that a mere literary analysis easily fall into dilemma, because the scope of their work deals only with language as a combination of words to convert message. Some questions whether the language expressed in literature may carry beyond what is supposed and that affects a generation of thoughts. A systematic wide range interdisciplinary seemed to find answers in the highly specialized language studies; this is what stylistics shows as it concerns. The interdisciplinary nature of the field means that stylistics typically cooperates some acquaintance with linguistics. As far as our research concerns, we attempted to purposefully relate this discipline with literary translation.
The main research question that leads us to accomplish this research paper was if the translator ability to transform the style of the original author would implicitly or explicitly transfer the meaning embedded in those stylistic features of the original text. A comparative analysis has to be underlined so we can grasp the traces of stylistic aspects in both translated and original texts. The Sand Child looked the best example for many reasons, mentioned in paper; we tried to provide a systematic analytic comparison between both styles. Eventually, we figured out the translator may succeed in reaching a faithful translation where he worked to keep stylistics prints of its original author; and thus, meaning upon the two texts is well-communicated. In fact, we believe, stylistics enhances our ability to interpret various meanings. Stylistics is more than studying language; it shortens distance between us and authors. A study that really merits much attention and further studies
"THE CORONA CRASH", BY GRACE BLAKELEY: A BOOK REVIEW
No full textIn this note, we come up with a review and presentation of the book “The Corona Crash: How the Pandemic Will Change Capitalism” by Grace Blakeley, a political and economics specialist who had various professional experiences, with companies such as KPMG and IPPR North in England.
In 2019 Grace released her early book, Stolen: How to Save the World from Financialization, She also worked as a journalist and a columnist for Tribune Newspaper.
Through her book - subject of this presentation and review-, the author exposed the fact that the current world has faced an epidemic and financial crisis because of the capitalist policies pursued in the leading countries for decades. In addition, she includes a reflexion by suggesting some solutions that maintain a socialist and environmental approach, based on social justice, solidarity, equality and the environment protecting policies
Women and politics in Algeria: essays on political representation
No full textGender and politics scholars have sought to determine whether there is a link between women’s descriptive representation, operationalized as the proportion of seats held by women in a national legislature, and women’s substantive representation, usually operationalized as laws that advance women’s rights. But, except for a few studies, the Arab world has not received significant attention which is surprising because the region has experienced a significant increase in women’s presence in politics. Further, most of this work has focused on democratic contexts, obscuring whether hypothesized links between women’s descriptive and substantive representation work in the same way in authoritarian contexts. To fill these gaps in the literature, I focus on the case of Algeria, where women’s presence in parliament increased from 8% to 31.6% after the adoption of a gender quota in 2012.
Drawing on in-depth interviews with a wide range of stakeholders, my research examines the backgrounds of women elected, constituency service priorities, legislative dynamics, and women’s agency. I argue that the “authoritarian toolkit,” i.e., the resources available to authoritarian governments to manage and control political outcomes, shapes women’s descriptive, substantive, and symbolic representation in ways that are distinct from how these dynamics operate in more democratic contexts.
While women parliamentarians reject the notion that they have an obligation to introduce and pass women’s rights laws, they invest time in helping their male and female constituents solve their everyday problems to challenge the notion that women do not belong in politics. Therefore, there may not be strong links between women's descriptive and substantive representation. However, the efforts of elected women on behalf of their male constituents may advance women’s symbolic representation by demonstrating women's abilities in the political realm.Ph.D.Includes bibliographical reference
Le discours politique des islamistes marocains au pouvoir : le discours populiste
No full textAt the end of this chapter entitled "Conflictual affective discourse", the study focused on a number of legitimising discursive strategies mobilised by Benkirane. In fact, the discourses that we have tried to analyse are part of a context marked by a social tension unseen in the history of Morocco (after the Arab Spring). These social realities, marked by a tension, or even a calculation of ideological repositioning between Islamists, communists, socialists, technocrats, etc., are, from the sociolinguistic interactional point of view, manifest in the discourse where the speaker seeks to impose his identity. This observation has led us to set up a typology that better defines this conflictual context, hence the interest in the grid developed by Windisch, whose author insists considerably on the internal functioning of a conflictual discourse produced in a situation of tension.
All the studies aimed at analysing legitimating discourse agree on two fundamental points: on the one hand, discourse is perceived as a linguistic production anchored in symbolic relations of force, negotiation, manipulation and persuasion between individuals; on the other hand, in order for each of them to achieve their objectives, the social actor is confronted with certain constraints in order to convey the meaning he or she aims for. In addressing the issue of dramatization in the so-called populist discourse, Patrick Charaudeau insists considerably on the affective dimension in the interaction with the mass.
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