1,721,152 research outputs found
Comparative genomic between Muscadinia rotundifolia and Vitis vinifera to facilitate the resistance genes identification
No full textMuscadinia rotundifolia est une espèce de la famille des Vitaceae. C’est un sous-genre du genre Vitis, le deuxième sous-genre étant celui des Euvitis qui comprend l’espèce cultivée Vitis vinifera (2n=38). M. rotundifolia (2n=40) est une source de résistance aux maladies très importante pour l’amélioration de la vigne. Son génome commence seulement à être décrit avec deux cartes génétiques récemment publiées. Ma thèse a consisté à utiliser des ressources génomiques chez M. rotundifolia cv Regale (banque BAC, collection de séquence d’extrémités de BAC ou BES et séquences de BACs) pour caractériser le génome de cette espèce en comparaison avec celui de V. vinifera. Les résultats obtenus ne montrent pas de différence importante entre les génomes des deux espèces en termes de composition du génome en bases (GC%), en séquences codantes ou en éléments répétés. De même, à une échelle globale, la famille de gènes NBS-LRR semble être similaire en termes de nombre et de balance entre les sous-familles. A une échelle plus fine cependant (carte physique et séquences de BAC), des remaniements relativement importants sont observés dans des régions portant cette famille de gènes, aboutissant parfois à des contenus différents en gènes, de région normalement homologues : duplication différentielles de gènes, présence/absence de gènes.Muscadinia Rotundifolia is a species of the Vitaceae family. It is a sub-genus of the Vitis genus along with the Euvitis sub-genus, which the cultivated species Vitis vinifera belongs to. M. rotundifolia (2n=40) is a very important source of resistance to diseases in grapevine breeding programs. Its genome is only starting to be described with the recent publication of two genetic maps. The present study aimed at using M. rotundifolia cv Regale genomic resources (BAC library, BAC end sequences or BES, BAC sequences) in order to characterize the genome of this species in comparison with the genome of V. vinifera. The results showed that there is no striking difference between the two species in term of base composition (GC %), repeats frequency and gene space. The NBS LRR gene family also seems to be globally quite similar between the two species in terms of numbers and balance between subfamilies. At a finer scale (physical map and BAC sequence), frequent rearrangements are observed in genomic regions carrying the NBS-LRR gene family sometimes clearly associated with a different gene content between the two species in homologous regions: differential gene duplication, presence/absence of genes
Genetic architecture of quantitative traits in trees: evolution of tools and methods
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Genetic architecture of quantitative traits in trees: evolution of tools and methods
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Resilience of genetic diversity in forest trees over the Quaternary
Full text linkThe effect of past environmental changes on the demography and genetic diversity of natural populations remains a contentious issue and has rarely been investigated across multiple, phylogenetically distant species. Here, we perform comparative population genomic analyses and demographic inferences for seven widely distributed and ecologically contrasting European forest tree species based on concerted sampling of 164 populations across their natural ranges. For all seven species, the effective population size, Ne, increased or remained stable over many glacial cycles and up to 15 million years in the most extreme cases. Surprisingly, the drastic environmental changes associated with the Pleistocene glacial cycles have had little impact on the level of genetic diversity of dominant forest tree species, despite major shifts in their geographic ranges. Based on their trajectories of Ne over time, the seven tree species can be divided into three major groups, highlighting the importance of life history and range size in determining synchronous variation in genetic diversity over time. Altogether, our results indicate that forest trees have been able to retain their evolutionary potential over very long periods of time despite strong environmental changes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Study and understanding of the genetic and molecular determinism of flowering in sweet cherry (Prunus avium)
No full textChez les espèces fruitières, la floraison est un évènement majeur qui influencera fortement la fructification. Ce processus, finement régulé par de nombreux facteurs génétiques et environnementaux, est encore peu connu. Chez le cerisier doux (Prunus avium), les fleurs ne s’épanouissent qu’après avoir satisfait des besoins en froid et en chaud. Les effets du changement climatique sur la floraison sont déjà notables et pourraient induire d’importantes pertes économiques. La compréhension des déterminants génétiques et moléculaires impliqués dans la floraison permettra l’amélioration des programmes de sélection variétale visant l’obtention d’arbres adaptés aux futures conditions climatiques. L’objectif de cette thèse est d’accroître les connaissances sur ces déterminants et d’identifier les gènes contrôlant la floraison chez le cerisier. En étudiant les deux familles intra spécifiques ‘Regina’ × ‘Lapins’ et ‘Regina’ × ‘Garnet’, la détection de nombreux quantitative trait loci (QTL) sur l’ensemble des groupes de liaisons (GL) a permis de confirmer la forte implication des besoins en froid dans la floraison ainsi que la complexité de ces caractères. Un QTL à effet majeur a été localisé sur le GL4. Dans les régions couvertes par les QTL contrôlant la date de floraison, une centaine de gènes candidats (GC) pour ce caractère a été identifiée. Un sous ensemble de ces GC a ensuite été étudié pour leur expression au cours du développement des bourgeons par PCR quantitative (qPCR). A terme, ces travaux serviront de bases pour l’identification et la sélection de gènes qui permettront l’obtention de génotypes adaptés aux futures conditions climatiques.In fruit species, the flowering is a major event which strongly influences fructification. This process tiny controlled by many genetic and environmental factors is still little known. In sweet cherry (Prunus avium), flowers open out only after having satisfied chill and heat requirements. The effects of climate change on the flowering are already notable and could induce important economic losses. Identification of genetic and molecular determinants involved in the flowering will allow the improvement of varietal selection programs to obtain trees adapted to future climate conditions. Objective of this thesis is to increase the knowledge of these determinants and identify genes involved in flowering in sweet cherry. By studying two intraspecific progenies ‘Regina’ × ‘Lapins’ and ‘Regina’ × ‘Garnet’, detection of many quantitative trait loci (QTL) on all linkage groups (LG) has enabled us to confirm the strong involvement of chill requirements in the flowering as well as the complexity of these traits. QTL with major effect was localized on the LG4. In regions covered by all the QTLs controlling flowering date, a hundred candidate genes (CG) for this trait was identified. A subset of these GC was then studied for their expression during development of buds by quantitative PCR (qPCR). In the long term, this work will serve as a basis for the identification and selection of genes that allow obtaining genotypes adapted to future climate conditions
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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