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Binding and Saturation of Nuclear MatterBhargava, Purna 09 1900 (has links)
<p> Using the reference spectrum method the G-matrix elements, and hence the binding energy of an infinite nucleus is calculated. Three modern potentials. two of which are hard core and one soft core are used. This formalism is then extended to a finite nuclei and spin orbit splittings around some closed shell nuclei are calculated. Both for binding energy and spin orbit splittings fairly good agreement with experiment is obtained. </p> / Thesis / Doctor of Philosophy (PhD)
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Plant-Herbivore Interactions and Evolutionary Potential of Natural Arabidopsis lyrata PopulationsPuentes, Adriana January 2012 (has links)
In this thesis, I combined field, greenhouse and common-garden experiments to examine the ecological and evolutionary consequences of plant-herbivore interactions and the genetic architecture of fitness-related traits in the insect-pollinated, self-incompatible, perennial herb Arabidopsis lyrata. More specifically, I examined (1) whether damage to leaves and inflorescences affects plant fitness non-additively, (2) whether trichome production is associated with a cost in terms of reduced tolerance to leaf and inflorescence damage, (3) whether young plant resistance to a specialist insect herbivore varies among populations, and (4) whether the evolution of flowering time, floral display and rosette size is constrained by lack of genetic variation or by genetic correlations among traits. A two-year field experiment in a Swedish population showed that damage to rosette leaves and to inflorescences can affect both current and future plant performance of A. lyrata, and that effects on some fitness components are non-additive. A two-year field experiment in another Swedish population indicated that trichome-producing plants are not less tolerant than glabrous plants to leaf and inflorescence damage. In a greenhouse experiment, acceptability of young plants (5-6 weeks old) to ovipositing females and damage received by Plutella xylostella larvae varied considerably among twelve A. lyrata populations. Both oviposition and leaf damage were positively correlated with rosette size, but trichome density in the trichome-producing morph was apparently too low at this developmental stage to influence resistance to P. xylostella. In a common-garden experiment, flowering time, floral display and rosette size varied among four Scandinavian A. lyrata populations, and displayed significant additive genetic variation in some populations. Yet, strong genetic correlations between flowering start and number of flowers, and between petal length and petal width suggest that these traits may not evolve independently. Taken together, the results indicate the need to consider possible long-term and non-additive effects of herbivore damage to different plant parts, that there is no trade-off between trichome production and tolerance to herbivory, that the importance of morphological defenses against herbivory may change through plant ontogeny, and that considerable genetic variation for traits such as flowering time and floral display can be maintained in natural plant populations.
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Effets de la dispersion du pollen à longue distance sur les capacités d'adaptation de populations de Hêtre commun le long d'un gradient altitudinal / Effets of long distance pollen dispersal on the adaptative potential of Beech populations along an altitudinal gradientGaüzère, Julie 31 October 2014 (has links)
La rapidité du changement climatique observé et prédit soulève la question de la vitesse à laquelle les espèces pourront s'adapter au climat futur. Les populations exposées aux changements de conditions environnementales peuvent s'adapter sur place (sans migration) grâce, dans un premier temps, à la réponse plastique des individus, puis, à long terme, par la réponse à la sélection (adaptation génétique). En situation d'environnement variable à la fois dans l'espace et le temps, les flux de gènes peuvent faciliter la diffusion d'allèles bénéfiques entre populations. L'objectif de cette thèse est d'étudier expérimentalement l'interaction entre adaptation et dispersion pollinique à longue distance sur un gradient altitudinal de hêtre commun (Fagus sylvatica). Cette étude a été conduite à partir de trois populations de hêtre sur le versant Nord du Mont-Ventoux (de 900 m à 1400 m d'altitude). Douze traits fonctionnels (phénologiques, physiologiques et morphologiques) potentiellement adaptatifs ont été mesurés sur 60 descendances maternelles issues de ces populations (20 mères/population, 100 individus/mère) et placées en pépinière. Les résultats de cette thèse montrent que (i) les forts taux de pollen immigrant reçus par les populations (m = 56 %) n'empêchent pas l'émergence de patrons de différenciation adaptative, (ii) la sélection érode la variance génétique des traits, (iii) malgré l'existence de variance génétique pour tous les traits, les covariances génétiques entre traits peuvent affecter les taux et directions d'évolution future, et (iv) les flux de pollen contribuent à augmenter la variance génétique totale au sein des populations. Finalement, les populations à moyenne et hautes altitudes pourraient avoir les capacités de s'adapter au climat futur. / The rapidity of the climate change observed and predicted raises the issue of how fast species can adapt to future. In face of environmental change, populations can adapt without migrating thanks to their plastic response in a first time, and to their response to selection in the long term (genetic adaptation). In conditions of environment variable both in space and time, gene flow can enhance the spread of beneficial alleles between populations. The objective of this thesis is to experimentally measure the adaptive differentiation and the long-distance pollen dispersal along an elevational gradient of beech populations (Fagus sylvatica). In this study we investigated three beech populations located on the northern side of the Mont-Ventoux (from 900m to 1400m of elevation). Twelve potential adaptive functional traits (phenological, physiological and morphological) have been measured on 60 maternal families collected from these populations (20 mothers/population, 100 offspring/mother) and planted in nursery. The results of this thesis show that that (i) the strong pollen immigrant rate received by the populations (m = 56 %) did not their prevent adaptive differentiation, (ii) the action of natural selection erodes the genetic variance of the traits, (iii) despite significant genetic variance for all the traits, the genetic covariance between traits should affect the rate and direction of evolution in the future, and (iv) gene flow contribute to increase the total genetic variance within the populations. Finally, populations at medium and high elevations may have the potential to adapt to future climate.
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Evolução morfológica e modularidade / Morphological evolution and modulatoryMelo, Diogo Amaral Rebouças 01 October 2012 (has links)
Sistemas morfológicos quantitativos são descritos por medidas contínuas. A relação genética entre essas características dos indivíduos é representada pela matriz de covariância genética aditiva, a matriz G. Entender a evolução da matriz G, portanto, é de suma importância para compreender os padrões de diversificação encontrados na natureza. Neste trabalho estudamos modelos computacionais para a evolução de traços contínuos em populações naturais, sujeitas a variados tipos de seleção e condições internas, focando no problema da evolução dos padrões de integração e modularidade nessas populações. Testamos dois modelos com diferentes combinações de parâmetros em sua capacidade de reproduzir e elucidar padrões naturais. Seleção direcional correlacionada se mostrou uma força importante na criação desses padrões de covariação e a seleção estabilizadora correlacionada se mostrou fundamental para a manutenção desses padrões / Quantitative morphological systems are described by continuous measurements. The genetic relation between these characteristics of the individuals is represented by the genetic additive co-variance matrix, the G matrix. Understanding the evolution of the G matrix is, therefore, of paramount importance for proper interpretation of the patterns of diversification we observe in nature. In this work we study computational models for the evolution of quantitative traits in natural populations, subject to different natural selection and internal conditions, focusing on the problem of the evolution of the pattern of morphological integration and modularity. We test two models with different sets of parameters in their ability to reproduce and elucidate natural patterns. Directional correlated selection was necessary for the shaping of the patterns of morphological integration, and correlated stabilizing selection was fundamental to the maintenance of these patterns
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Evolução morfológica no crânio de Lemuriformes (Primates:Strepsirrhini) / Lemuriformes (Primates: Strepsirrhini) cranial morphological evolutionPenna, Anna Paula Casselli 27 July 2016 (has links)
O principal objetivo deste estudo foi investigar os processos responsáveis pela evolução morfológica craniana de primatas da subordem Strepsirrhini, com maior ênfase ao clado endêmico à ilha de Madagascar. Sistemas multidimensionais morfológicos como o crânio descrevem a quantidade de variação disponível para atuação de processos evolutivos. A partir de 27 marcos anatômicos cranianos e 39 distâncias euclidianas estimei matrizes de variância e covariância fenotípicas (Matrizes P) para 40 espécies das sete famílias viventes de Strepsirrhini e duas espécies do gênero Tarsius. Utilizei a abordagem da genética quantitativa para investigar o padrão de variação nas matrizes P dessa linhagem de primatas, conjuntamente com um par de matrizes fenotípica e genética de Saguinus fuscicolis. Para investigar a estabilidade e conservção do padrão da estrutura de variação ao longo da diversidade deste clado de primatas compararei estas matrizes através de dois métodos complementares que me permitiram avaliar a distribuição da variação no morfoespaço (Random Skewers) e o compartilhamento de direções de variação (Krzanowski) das matrizes. Os resultados obtidos sugerem uma estabilidade das matrizes, possivelmente mantida por seleção estabilizadora interna comum ao clado, aos demais primatas e mamíferos em geral. Esses resultados de comparação de matrizes são apresentados no Capítulo 1 e corroboram a conjectura de Cheverud, indicando que as matrizes cumprem o pressuposto de similaridade estrutural entre as matrizes P e a matriz G. Além disso o padrão de variação apresentou um sinal filogenético e algumas das diferenças observadas nas matrizes parecem estar relacionadas com fatores de dieta. No Capítulo 2 investiguei a evolução da divergência morfológica craniana em um conjunto de 70 espécies, onde testei a hipótese nula de deriva genética como explicação suficiente para a divergencia entre as médias das espécies. Esta hipótese foi avaliada dentro das expectativas de modelos da genética quantitativa através de duas metodologias. Tais testes avaliam a proporcionalidade de variação dentro (W) e entre grupos (B) sob perspectivas complementares. Com o teste de regressão investiguei a manutenção da quantidade de variação associada a cada eixo de variação, e com o teste de correlação avaliei o alinhamento entre estes eixos. Rejeitamos a H_0 em diversos pontos da árvore que representam eventos de cladogenese a nível de família e gênero. Nestes casos aceitamos a H_1 de seleção natural e vemos que a maior parte da diversificação da linhagem de primatas de Madagascar foi influenciada por seleção direcional envolvendo tamanho e alterações anatômicas relacionadas a dieta / The main goal of this study was to investigate the evolutionary processes responsible for Strepsirrhini cranial morphological evolution. Multidimensional morphological structures like the cranium can describe the amount of variance available to evolution. We used 27 landmarks and 39 euclidean distances between them to describe the variation in the cranium. We used a broad phylogenetic scaled comparison of cranial P matrices representing 40 species of Strepsirrhini primates combined to a pair of Saguinus fuscicolis G and P to investigate the stability of variance structure along this lineage. Our results show a relative stability in the patterns of variance and covariance of the clade and that P matrices can be considered as surrogates to its underling G. We also report a high association between matrix similarity and phylogenetic distance. We investigated particular contributions of each trait to matrix dissimilarity through a evolutionary perspective considering the main dietary shifts observed in the clade. Our results suggest that differences in observed patterns of variation can be attributed to characters with heterogeneity in the degree of stabilizing selection in the adult cranium and to differences in directional selection involved in chewing of specialized feeding behavior. Under the quantitative genetics theory lies an expectation for the evolution of average phenotypes that if populations have diverged by random processes, patterns of within and between-taxon morphological variation should be proportional. In chapter 2 we tested the null hypothesis that genetic drift is a sufficient explanation to observed divergence in cranial multivariate means of 70 Strepsirrhini primates. We detected deviations from neutrality along the whole clade of Strepsirrhini and specially in more inclusive nodes. We argue that this deviations reflect important historical shifts in the evolution of the clade associated with directional selection for size and in anatomical features related with diet
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Evolução morfológica no crânio de Lemuriformes (Primates:Strepsirrhini) / Lemuriformes (Primates: Strepsirrhini) cranial morphological evolutionAnna Paula Casselli Penna 27 July 2016 (has links)
O principal objetivo deste estudo foi investigar os processos responsáveis pela evolução morfológica craniana de primatas da subordem Strepsirrhini, com maior ênfase ao clado endêmico à ilha de Madagascar. Sistemas multidimensionais morfológicos como o crânio descrevem a quantidade de variação disponível para atuação de processos evolutivos. A partir de 27 marcos anatômicos cranianos e 39 distâncias euclidianas estimei matrizes de variância e covariância fenotípicas (Matrizes P) para 40 espécies das sete famílias viventes de Strepsirrhini e duas espécies do gênero Tarsius. Utilizei a abordagem da genética quantitativa para investigar o padrão de variação nas matrizes P dessa linhagem de primatas, conjuntamente com um par de matrizes fenotípica e genética de Saguinus fuscicolis. Para investigar a estabilidade e conservção do padrão da estrutura de variação ao longo da diversidade deste clado de primatas compararei estas matrizes através de dois métodos complementares que me permitiram avaliar a distribuição da variação no morfoespaço (Random Skewers) e o compartilhamento de direções de variação (Krzanowski) das matrizes. Os resultados obtidos sugerem uma estabilidade das matrizes, possivelmente mantida por seleção estabilizadora interna comum ao clado, aos demais primatas e mamíferos em geral. Esses resultados de comparação de matrizes são apresentados no Capítulo 1 e corroboram a conjectura de Cheverud, indicando que as matrizes cumprem o pressuposto de similaridade estrutural entre as matrizes P e a matriz G. Além disso o padrão de variação apresentou um sinal filogenético e algumas das diferenças observadas nas matrizes parecem estar relacionadas com fatores de dieta. No Capítulo 2 investiguei a evolução da divergência morfológica craniana em um conjunto de 70 espécies, onde testei a hipótese nula de deriva genética como explicação suficiente para a divergencia entre as médias das espécies. Esta hipótese foi avaliada dentro das expectativas de modelos da genética quantitativa através de duas metodologias. Tais testes avaliam a proporcionalidade de variação dentro (W) e entre grupos (B) sob perspectivas complementares. Com o teste de regressão investiguei a manutenção da quantidade de variação associada a cada eixo de variação, e com o teste de correlação avaliei o alinhamento entre estes eixos. Rejeitamos a H_0 em diversos pontos da árvore que representam eventos de cladogenese a nível de família e gênero. Nestes casos aceitamos a H_1 de seleção natural e vemos que a maior parte da diversificação da linhagem de primatas de Madagascar foi influenciada por seleção direcional envolvendo tamanho e alterações anatômicas relacionadas a dieta / The main goal of this study was to investigate the evolutionary processes responsible for Strepsirrhini cranial morphological evolution. Multidimensional morphological structures like the cranium can describe the amount of variance available to evolution. We used 27 landmarks and 39 euclidean distances between them to describe the variation in the cranium. We used a broad phylogenetic scaled comparison of cranial P matrices representing 40 species of Strepsirrhini primates combined to a pair of Saguinus fuscicolis G and P to investigate the stability of variance structure along this lineage. Our results show a relative stability in the patterns of variance and covariance of the clade and that P matrices can be considered as surrogates to its underling G. We also report a high association between matrix similarity and phylogenetic distance. We investigated particular contributions of each trait to matrix dissimilarity through a evolutionary perspective considering the main dietary shifts observed in the clade. Our results suggest that differences in observed patterns of variation can be attributed to characters with heterogeneity in the degree of stabilizing selection in the adult cranium and to differences in directional selection involved in chewing of specialized feeding behavior. Under the quantitative genetics theory lies an expectation for the evolution of average phenotypes that if populations have diverged by random processes, patterns of within and between-taxon morphological variation should be proportional. In chapter 2 we tested the null hypothesis that genetic drift is a sufficient explanation to observed divergence in cranial multivariate means of 70 Strepsirrhini primates. We detected deviations from neutrality along the whole clade of Strepsirrhini and specially in more inclusive nodes. We argue that this deviations reflect important historical shifts in the evolution of the clade associated with directional selection for size and in anatomical features related with diet
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Evolução morfológica e modularidade / Morphological evolution and modulatoryDiogo Amaral Rebouças Melo 01 October 2012 (has links)
Sistemas morfológicos quantitativos são descritos por medidas contínuas. A relação genética entre essas características dos indivíduos é representada pela matriz de covariância genética aditiva, a matriz G. Entender a evolução da matriz G, portanto, é de suma importância para compreender os padrões de diversificação encontrados na natureza. Neste trabalho estudamos modelos computacionais para a evolução de traços contínuos em populações naturais, sujeitas a variados tipos de seleção e condições internas, focando no problema da evolução dos padrões de integração e modularidade nessas populações. Testamos dois modelos com diferentes combinações de parâmetros em sua capacidade de reproduzir e elucidar padrões naturais. Seleção direcional correlacionada se mostrou uma força importante na criação desses padrões de covariação e a seleção estabilizadora correlacionada se mostrou fundamental para a manutenção desses padrões / Quantitative morphological systems are described by continuous measurements. The genetic relation between these characteristics of the individuals is represented by the genetic additive co-variance matrix, the G matrix. Understanding the evolution of the G matrix is, therefore, of paramount importance for proper interpretation of the patterns of diversification we observe in nature. In this work we study computational models for the evolution of quantitative traits in natural populations, subject to different natural selection and internal conditions, focusing on the problem of the evolution of the pattern of morphological integration and modularity. We test two models with different sets of parameters in their ability to reproduce and elucidate natural patterns. Directional correlated selection was necessary for the shaping of the patterns of morphological integration, and correlated stabilizing selection was fundamental to the maintenance of these patterns
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Population differentiation in Lythrum salicaria along a latitudinal gradientOlsson, Katarina January 2004 (has links)
<p>In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. </p><p>A common-garden experiment demonstrated latitudinal variation in life-history, and phenology of growth and reproduction among L. salicaria populations sampled across Sweden. Flower morphology varied significantly among populations, but was, with the exception of calyx length, not related to latitude of origin. A second experiment, which included two Swedish, two Dutch, and two Spanish populations, indicated that the latitudinal gradient in reproductive and vegetative phenology might extend throughout Europe.</p><p>A quantitative-genetic study of two Swedish populations revealed significant additive genetic variation for all phenological and morphological traits investigated. The G matrices of the populations differed significantly according to common principal component analysis, and genetic correlations within the study populations did not strictly correspond to trait correlations observed among populations.</p><p>In a field study, I detected directional selection through female function for larger inflorescences in two consecutive years. Relative fitness increased disproportionately with inflorescence size in the year when supplemental hand-pollination indicated that pollen limitation was severe. Genetic correlations with inflorescence size considerably influenced predicted response to selection in other characters.</p><p>Taken together, the results suggest that among-population differences in phenology and life-history in L. salicaria have evolved in response to latitudinal variation in length of the growing season. They demonstrate that the evolutionary potential of local populations may be considerable. The genetic covariance structure substantially influences predicted short-term evolutionary trajectories. However, the weak correspondence between genetic correlations documented within populations and trait correlations among populations, suggest that the G matrix has not imposed strict constraints on patterns of among-population differentiation.</p>
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Population differentiation in Lythrum salicaria along a latitudinal gradientOlsson, Katarina January 2004 (has links)
In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. A common-garden experiment demonstrated latitudinal variation in life-history, and phenology of growth and reproduction among L. salicaria populations sampled across Sweden. Flower morphology varied significantly among populations, but was, with the exception of calyx length, not related to latitude of origin. A second experiment, which included two Swedish, two Dutch, and two Spanish populations, indicated that the latitudinal gradient in reproductive and vegetative phenology might extend throughout Europe. A quantitative-genetic study of two Swedish populations revealed significant additive genetic variation for all phenological and morphological traits investigated. The G matrices of the populations differed significantly according to common principal component analysis, and genetic correlations within the study populations did not strictly correspond to trait correlations observed among populations. In a field study, I detected directional selection through female function for larger inflorescences in two consecutive years. Relative fitness increased disproportionately with inflorescence size in the year when supplemental hand-pollination indicated that pollen limitation was severe. Genetic correlations with inflorescence size considerably influenced predicted response to selection in other characters. Taken together, the results suggest that among-population differences in phenology and life-history in L. salicaria have evolved in response to latitudinal variation in length of the growing season. They demonstrate that the evolutionary potential of local populations may be considerable. The genetic covariance structure substantially influences predicted short-term evolutionary trajectories. However, the weak correspondence between genetic correlations documented within populations and trait correlations among populations, suggest that the G matrix has not imposed strict constraints on patterns of among-population differentiation.
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The Quantitative Genetics of Good Genes: Fitness, Male Display, and Female PreferenceDelcourt, Matthieu 12 October 2011 (has links)
The ultimate goal of my thesis is to develop a better understanding of the contribution of indirect benefits (i.e. good genes) to the evolution of female mate preferences. It is genetic variance in, and genetic correlations (covariances) among, male sexual displays, female preferences for them, and fitness that in part determine the degree to which females preferring certain male displays over others will gain an indirect benefit by having higher fitness offspring. Recent advances in quantitative genetic theory provide the mathematical means for quantifying the strength of indirect selection for female mate preferences (Kirkpatrick and Hall 2004), at least under certain conditions, but there are few empirical systems for which such data exist (Brooks and Endler 2001; Qvarnström et al. 2006). I have undertaken a classic half-sibling breeding design with the ultimate goal of estimating the specific parameters of this model in a population of the Australian fruit fly Drosophila serrata. The breeding design was performed across two environments - one to which the population was well adapted and a novel environment to which it was not - thereby also providing insight into genotype-by-environment interactions for this suite of traits and their effects on good genes indirect benefits in a novel environment. General insight is also gained into the genetic covariance of male and female fitness and the prevalence of intralocus sexual conflict, the quantitative genetic basis of female mate preferences for multiple male traits, the condition-dependence of these traits, and the genetic association between sexual displays and fitness when mutation-selection balance is inferred. My results advocate caution in the application of existing theory to quantify the strength of indirect selection, suggesting that a good genes process may be fundamentally different when the exaggeration of sexual displays is eventually halted and an equilibrium is reached between opposing selection.
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