Les symbioses, en permettant l’acquisition de nouvelles fonctions, ont joué un rôle majeur dans l’évolution des organismes. Cette thèse, vise à comprendre les mécanismes moléculaires et évolutifs qui font des polydnavirus des symbiontes indispensables au succès parasitaire de guêpes parasitoïdes. Pour cela, nous avons étudié l’évolution des gènes viraux et les fonctions physiologiques potentiellement ciblées chez l’hôte. Nous avons montré que l’évolution des gènes viraux était caractérisée par des duplications et une divergence rapide, et répondait à des pressions de sélection positive. Chez l’hôte, nous avons montré que des protéases à cystéine, potentiellement ciblées par des gènes viraux, étaient régulées au cours du parasitisme au niveau de la transcription et de la traduction, suggérant que ces protéines doivent jouer un rôle important au cours du parasitisme. Il reste maintenant à déterminer quelle est la fonction de ces protéines et leur influence sur l’évolution des gènes viraux. / Symbioses have largely contributed to the evolution of species by providing new functions enabling niche colonization. Here, our aim was to study the molecular evolution of virulence factors encoded by polydnaviruses engaged in a mutualist association with parasitoid wasps and which are essential for parasitism success. We studied both PDV genes and their Lepidopteran host targets to determine how these genes evolved and the host functions targeted. We showed that natural selection has largely contributed to the evolution of cystatin and protein-tyrosine- phosphatase viral genes. 3D structure modelling showed that selection acted in cystatin active sites. Moreover, we underlined the dynamic evolution of PDV genes mainly explained by gene duplication processes. In the host, potential cystatin targets, cysteine proteases, were shown to be regulated during parasitism both at the gene and the protein level. These results emphasized the important role played by these proteins against invaders. To understand both evolutionary and mechanistic processes involved in this interaction, it is now necessary to determine the function of cysteine proteases and to study how virus gene evolution could be shaped by host defence factors.

Star formation in the Cam OB1 region is investigated. Star formation, in general, is considered in terms of three elements: a) the structural relationship between the parent molecular clouds and newly formed stars, b) the temporal evolution of the parent molecular clouds, and c) the probability of the occurrence of star formation. Star formation in Cam OB1 over the range in l and b considered in this work, is concentrated in the vicinity of Cam R1 and appears to have led to the formation of three distinct stellar groups: a) Group I. formed ~ 1 - 50 x 106 yr ago, and located spatially and kinematically between two CO complexes, b) Group II. formed ~ 1 - 3 x 106 yr ago. and coincident with one of the previously mentioned complexes, and c) Group III. the youngest group, formed ~ I - 20 x 104 yr ago, and located at the current point of intersection between the two complexes in (a). The mass function (MF) for Groups I and II is similar to the cloud mass function of the parent molecular clouds, i.e. a power-law with exponent α ~ 2. A similar analysis for the Group III stars and associated molecular clouds cannot be performed due to the relatively small numbers in both samples. The star forming efficiency (SFE) in all cases is ~ 1%. It is proposed that cloud-cloud collisions between the CO complexes in the region triggered the formation of Groups I and III, while Group II was produced by a shock induced by the radiation pressure and stellar winds from the stars in Group I. An analysis of the molecular cloud structure in Cam OB1 and the background Perseus arm also shows that the clouds in both regions are turbulent, and typical of clouds seen elsewhere in the Galaxy. However, the clouds in Cam OB1 show a large dispersion in the degree with which they are self-gravitating, with the larger, warmer clouds being gravitationally bound. The principal data set for this work comprises fully sampled [special characters omitted] observations of the western half of Cam OB1, which were obtained at the Center for Astrophysics during the winter of 1992-1993. These data have an effective resolution of 10', a velocity resolution of 0.65 km s-1, and a sensitivity of 0.115 K. High resolution (20") observations of the [special characters omitted] transition of the most active star forming region were obtained with the James Clerk Maxwell Telescope during the winter of 1994-1995. These observations led to the discovery of a second outflow. AFGL 490 – iki, associated with IRAS 03234+5843, in the immediate vicinity of the very well-studied molecular outflow AFGL 490. Additional observations of the [special characters omitted], taken with the 26m telescope at the Dominion Radio Astrophysical Observatory during the fall of 1994, did not reveal any such masering activity in the Cam OB1 region, but did lead to the discovery of a new maser, associated with IRAS 02455+6034. in the background Perseus arm. / Graduate

No description available.

No description available.

The origin, function and evolution of the branchiostegal rays, the related opercular and gular bones and associated hyoid elements were investigated in teleostome fishes. Alizarin, skeletal or alcoholic specimens of over half the living families (over 240) and all the living orders of teleostome fishes with branchiostegals were examined. Literature provided data for most of line remaining living and fossil families and orders. Several evolutionary trends became apparent; a tendency for number of branchiostegals to decrease, following Williston's Law; increasing separation of mandibular and hyoid arches; and an increase in number and complexity of hyoid elements. In the development of hyoid elements, but not of branchiostegal rays, the ontogenetic sequence paralleled the phylogenetic sequence. Examination of the unusual adult hyoid relationships in the neotenic Schindleria showed it to resemble the larval condition of normal fishes. The condition in the tiny goby, Mistichthys, is similar. The structure of the branchiostegal series and hyoid elements proved valuable in tracing the relationships of fishes. Major findings include: Hiodontidae were found not be be closely related to the Notopteridae; the Notopteridae and osteoglossoid families to be related to the mormyriforms; the Neoscopelidae and Myctophidae to differ from other myctophiforms; the ophidioids to require ordinal separation from the Perciformes and placement near the Gadiformes and Ateleopiformes; the Amblyopsidae to belong in the Percopsiformes; the Anabantoidei and Ophicephaloidei to be closely related suborders of common ancestry deserving placement in the same order; the Beloniformes to differ from most other orders in the loss of the interhyal and upper hypohyal; and the Echeneiformes to differ from most Perciformes in the possession of 8-11 branchiostegals. The number of branchiostegals was found to be influenced by posterior extension of the jaws, small body length, feeding habits, gill membrane attachment and deepsea existence. / Science, Faculty of / Zoology, Department of / Graduate

We have examined the late-type stellar content of 3 disk fields of NGC 2403 using VRI CCD photometry. The AGB luminosity function has been constructed and differs strongly with that of the LMC. Notably, even fewer bright AGB stars are seen in NGC 2403 than in the LMC. The shape of the AGB luminosity function for the innermost field, however, indicates that a recent burst of star formation may have occurred. Red and blue supergiants and HII regions are also identified in the field to support this. The relative distance modulus between NGC 2403 and the LMC is derived to be 8.90 and the true distance modulus to NGC 2403 is (m - M)₀ = 27.40 ± 0.24. The carbon to M star number for the innermost field is 8/17 which corresponds to [Fe/H] = -0.35. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This thesis discusses dialectical and institutional continuity in relation to evolutionary thought.

Ce travail a pour objectif de proposer des méthodes pour améliorer la compréhension des processus d’évolution de la Loire moyenne sur quelques décennies. L’analyse des évolutions morphologiques est réalisée en découpant le secteur d’étude en tronçons géomorphologiquement homogènes. Une diminution de la pente et une réduction de la largeur de la bande active entre 1955 et 1996 sont observées. Suite à l’arrêt des extractions (1996),les ajustements se poursuivent de façon plus modérés.Des simplifications géométriques et hydrologiques sont ensuite introduites dans un modèle de transport solide unidimensionnel (RubarBE) afin d’être comparées aux résultats obtenus avec lag éométrie détaillée et la chronique de débit complète. La géométrie simplifiée permet une modélisation des évolutions du lit pertinente tout en réduisant le temps de calcul ; la simplification des chroniques de débit illustre la sensibilité des modèles numériques hydro-sédimentaires à l’hydrologie. Enfin, l’application des simplifications sur l’ensemble de la Loire moyenne sur la période 1996-2006 confirme les tendances observées par l’analyse des données. / This work deals with the development of methods that sought to assess channel changes of a long anthropogenised river over several decades. These methods are applied on the Middle Loire River (France). Channel changes are evaluated by dividing the study reach into geomorphically distinct river reaches. A narrowing of the active channel width and a decrease of the river bed slope were observed between 1955 and 1996. Since in stream gravel mining stopped (1996), river adjustments have continued at a slower rate. Simplified geometry and simplified hydrographs are then derived and introduced into a one dimensional sediment transport model (RubarBE). The simplified geometry allows pertinent calculation of the river bed evolution whilst reducing calculation time. The use of simplified hydrographs highlights the sensitivity of sediment transport modelling to hydrology. Finally, the application of the simplifications to the whole Loire Moyenne River confirms the general trend observed between 1996 and 2006.

Dogs (Canis lupus familiaris) and wolves (Canis lupus lupus) share genotypes, which are nearly identical, but their behavioral phenotypes are very different. It has been repeatedly hypothesized that these adult behavioral differences are the result of heterochronic changes, or differences during the course of development. This dissertation investigates three major behavioral differences between these two morphs: (1) Interspecies socialization: both dogs and wolves are capable of forming interspecies attachments, most commonly with humans, but wolves require more intense exposure to reach a less intense attachment. (2) Expression of species-typical motor patterns: while dogs and wolves have the same species-typical motor patterns, they express them at different rates and in different frequencies. (3) Frequency of barking: while both dogs and wolves bark, dogs bark at a much higher frequency than wolves. The primary objective of this dissertation is to determine if behavioral differences between polymorphs of the genus Canis are the result of heterochrony. Fifty-two Canis pups including, both mother- and hand-reared dogs (Canis lupus familiaris) represented by two breeds (Border collies and German shepherds) and hand-reared wolves were observed. Frequency of motor pattern display was recorded from two to eight weeks of age in all groups. Responses of pups to olfactory, auditory, and visual stimuli were also tested weekly from two to seven weeks of age. Groups were then compared on the timing of the onset and frequency of expression of foraging motor patterns (orient, eye, stalk, chase, and grab-bite) and the onset of their ability to orient towards olfactory, auditory, and visual stimuli. My results demonstrate that small changes in the timing of the critical period of socialization in relationship to the development of the sensory systems do account for differences in the ability to form interspecies social attachments between dogs and wolves. The data also demonstrate that there are heterochronic differences in the development of species typical foraging motor patterns between dogs and wolves. However, these changes alone do not explain the fragmenting of breed-typical sequences in relation to functional wolf sequences. Investigation of barking frequency was accomplished by searching previous literature to define acoustic measurements, which distinguish the bark from other vocalizations. This definition was then used to determine in what situations the bark occurred in dogs, wild Canis species, other mammals, and birds. Barking occurs in a large variety of mammals and birds, and is motivated by conflicting internal states associated with mobbing. This is supported by the acoustic structure of the bark itself and the contexts in which mammals, including dogs and other members of the genus Canis, and birds use the bark vocalization.

A great challenge that biology faces is in integrating phenomena from different scales. On the micro scale of the spectrum, we can measure subcellular processes, like gene expression and regulation. On the macro scale, we can measure species level variation, ecological interactions, and the like. The challenge biology faces is in following the causal threads that lead individuals, populations, and ultimately, species to the variation in traits that we see in nature. The idea that there are cascades of causality that reduce to a microscopic scale is often referred to as the Genotype to Phenotype map (Houle and Govindaraju 2010). The Genotype to Phenotype map is ultimately a problem of measurement; what do we need to measure at each scale of interest in order to understand and, more importantly, predict variation elsewhere on the spectrum? This thesis is focused on two parts of the genotype-phenotype spectrum. The first chapter focuses on the macro scale, specifically on how traits maintain stasis across species. Here we use Drosophila melanogaster wing shape as a model to test whether stasis is explained by constraint or by stabilizing selection. We test for constraint with an artificial selection experiment on wing shape. We then test for stabilizing selection by measuring flight differences among selected and unselected flies and by testing for mate preference. In the second chapter, I focus on the micro scale by describing a method to measure the spatial properties of gene expression patterns. Quantitative measures of gene expression currently focus on mutations in the genome and/or the magnitude of expression. This ignores the spatial components of gene activity that are critical in the formation of pattern and the maintenance of growth during development. I describe methods to measure the spatial characteristics of genes that form discrete and continuous patterns of expression. I then give three examples of the method by quantitatively disrupting three genes and estimating the effects on a discrete and a continuous expression pattern. / A Thesis submitted to the Department of Biological Science in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2014. / November 04, 2014. / Includes bibliographical references. / David C. Houle, Professor Directing Thesis; Wu-Min Deng, Committee Member; Michelle N. Arbeitman, Committee Member.