Spelling suggestions: "subject:"enetic variation."" "subject:"benetic variation.""
71 |
Evolution of Intraspecific Genetic Differences Across Heterogeneous Environments and the Potential Impacts on Environmental RestorationYoko, Zebadiah Gaze January 2020 (has links)
Genetic differences evolve between seed sources of widely distributed species that can impact restoration success. Using the herbaceous perennial Geum triflorum (Pursh) as a model species, we examine genetic differences that evolve across a species’ range in both physiology and fitness. G. triflorum occurs across highly differentiated environments consisting of prairie and alvar habitats. Seeds were collected from 22 populations across three eco-geographic regions. Through a common garden experiment in the prairie environment, I first examined differences in physiological traits between source regions and populations. Significant regional differentiation was observed for a majority of traits assessed, with equal or greater trait variation observed at the population scale. Secondly, differences in fitness between source regions were assessed over a period of three years using the ASTER model. Despite being in the home environment, fitness was considerably lower in prairie-sourced plants than alvar sourced plants, both each year and in total.
|
72 |
Normal Mandibular Morphology of Inbred Mouse StrainsEdwards, Michelle Halum January 2004 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Even though the molecular events and pathways that underlie craniofacial development and morphogenesis are not fully understood, it is accepted that their orchestration is influenced by the interaction of genetic and environmental factors. Inbred mouse strains represent genetically homogenous groups of individuals. It is established that mice in one strain often differ quite remarkably from mice in other inbred strains. Those phenotypic differences make mice exceptional tools for the dissection of genetic factors that influence normal and abnormal craniofacial morphogenesis. While numerous investigations have focused on abnormal morphogenesis, a comprehensive study of normal craniometric morphology across multiple inbred strains of mice has not been previously performed. The Mouse Phenome Project, an international collaboration of investigators, was formed to systematically phenotype a collection of normal inbred mouse strains. The objectives of our studies were to determine and measure differences in quantitative mandibular traits/variables within and between different inbred mouse strains, and to assess sexual dimorphism through bilateral measurements of the hemimandibles. These studies were a component of the Mouse Phenome Project to collect normal craniometric data from 12 genetically heterogeneous inbred strains utilizing digital images from equal numbers of female and male mice at 7 to 8 weeks of age.
Our central hypothesis was that morphometric analysis of mandibular structures from genetically disparate inbred mouse strains would reveal quantifiable differences. The null hypothesis of no difference among the strains for mandibular measurements was rejected. Overall, CAST/Ei and MOLF/Ei were consistently small in size measured by body weight with small skeletal structures. There was no strong pattern of body weight and site of skeletal size in the mid and heavy weighted strains. Evidence of sexual dimorphism was supported. Overall, it appears males and females that have the least significance between them are in the DBA/2J strain, followed by A/J. The strain with the most significant difference between males and females is in the C3H/HeJ strain.
|
73 |
Assessment of genetic variation and population differentiation in invasive multiflora rose, Rosa multiflora Thunberg (Rosaceae) in northeastern OhioGhosh, Rajlakshmi 17 July 2009 (has links)
No description available.
|
74 |
Population genetics and breeding ecology of the rare clonal shrub, Spiraea virginiana (Rosaceae)Brzyski, Jessica R. 20 September 2011 (has links)
No description available.
|
75 |
Evolutionary Patterns and Processes in the Desert-Adapted Fern Genus Myriopteris (Pteridaceae)Grusz, Amanda Lee January 2014 (has links)
<p>This dissertation investigates the processes of hybridation, polyploidy, and apomixis and their roles in the evolution of myriopterid ferns. First, I examine patterns of hybridization in members of the Cheilanthes yavapensis complex using a suite of techiniques, ranging from molecules to morphology--including isozymes, spore measurements, and molecular phylogenetics based on chloroplast and nuclear DNA markers--to elucidate relationships in this notorious group of ferns. Second, I utilize the rules of traditional taxonomy set by the International Code of Botanical Nomenclature to recircucmscribe and resurrect the genus Myriopteris from within cheilanthoid ferns. This revised classification is bolstered by results from my molecular phylogenetic analysis of DNA sequence data in the subsequent chapter. Then, using morphological and cytological analyses, I examine the evolution of indument, leaf and rachis shape, vernation, chromosome number, and reproductive mode across the myriopterid tree. In my concluding chapter I develop microsatellite markers for the apomictic triploid, M. lindheiemeri, and explore whether premeiotic chromosome duplication facilitates the production of genetically distinct offspring in this otherwise asexual lineage.</p> / Dissertation
|
76 |
Ecological genetics of populations experiencing changing environmental conditionsHusby, Arild January 2010 (has links)
A major goal in evolutionary biology is to understand how ecological factors shape the phenotypic and genetic variation that we observe in natural populations and in this thesis I examine how rapid changes in temperature have influenced phenotypic and genetic variation in morphological and life history traits in long-term studies of great tits. In Chapter 1 I review what is known about the effects of environmental change on natural populations, and outline the quantitative genetic framework that is available to study genetic variation in natural populations. Much focus on the effects of climate change has concerned species’ phenology, far less attention has been given to other traits. In Chapter 2 I examine the effects changing environmental conditions have had on the proportion of females that produce second broods. Temperature operates mainly through indirect effects (such as food abundance) but may also have more direct effects. In Chapter 3 I show that over a 36 year period body size have declined in line with predictions from Bergmann’s rule and I explore the genetic basis of this decline and the environmental factors involved. Although we can learn much from population level responses, there is a great deal of additional information to be gained by studying between-individual responses. In Chapter 4 I therefore compare the multivariate pattern of between-individual variation in phenotypic plasticity and its genetic basis for laying date and clutch size, in two great tit populations. Environmental changes may also directly affect the expression of genetic variance as well as the strength of selection acting on a trait, and in Chapter 5 I show that, for laying date, the environment induces a positive covariance between strength of selection and the expression of additive genetic variance, something that may enhance the rate of adaptation. Finally, in Chapter 6 I discuss and summarise the wider implications of the findings from this thesis.
|
77 |
Mitochondrial DNA Sequence Variation in Populations of the Nine-Banded Armadillo (Dasypus novemcinctus)Elrod, Diana Adams 08 1900 (has links)
Four populations of nine-banded armadillos, Dasypus novemcinctus, were investigated in the south-central United States in order to assess genetic variation in an isolated population (Electric Island, Lake Hamilton, Garland County, Arkansas); a semi-isolated population (Arkansas Post, Arkansas County, Arkansas), and two free ranging populations (southern Arkansas and central Texas). A 233 basepair sequence of the D-loop region of mitochondrial DNA was sequenced in individuals from each population. Individuals and populations were compared to assess relatedness among populations and individuals. Higher sequence diversity was detected in the semi-isolated population, while lower sequence diversity was observed in the isolated and free ranging populations. Overall, all populations exhibited low genetic variation when compared to genetic variation for other mammals. The results support the hypothesis that rapid range expansion combined with the organism's unique reproductive strategies have promulgated low genetic variation in the North American populations of nine-banded armadillos.
|
78 |
Variabilita mitochondriální DNA u populací střední Evropy. / Mitochondrial DNA variability in the Central European populations.Veselá, Monika January 2015 (has links)
The aim of this thesis was to evaluate the genetic diversity of mtDNA of populations in Central Europe and to assess its relation to geographic distances and/or linguistic affiliation of individual populations. For this purpose, HVS-1 mtDNA segments of 194 individuals of 6 Slovak populations were sequenced. Basic parameters of genetic diversity were estimated for obtained sequences, and compared with similar data published by other authors (4 798 sequences of HVS-1 mtDNA segment of 42 population units in Central Europe in total). Intra-population analysis revealed a high level of gene and nucleotide diversity of studied populations, with values clearly decreasing from north to south. While the Slovak populations were bearing the highest rates of genetic diversity, the lowest values were detected in the Croatian populations. The results of ΦST distances point to a certain similarity of the Slavic population (Slovakia, Czech Republic, Poland, Slovenia, Serbia, Bosnia and Herzegovina), Germanic (Germany, Austria, Switzerland) as well as some groups from Hungary and Romania. As the most distant appeared especially the population of Croatia, which differed from almost all populations included in the study. AMOVA showed that the geographic division of population explains the layout of genetic variation...
|
79 |
Inheritance and genetic variation of shoot elongation before winter in oilseed rape (Brassica napus L.)Ghanbari, Mohammad 08 July 2016 (has links)
No description available.
|
80 |
Padrões de distribuição histórica, relações filogenéticas e filogeográficas de veado-mateiro-pequeno, Mazama bororo DUARTE, 1996 (Mammalia : Cervidae) /Mantellatto, Aline Meira Bonfim. January 2016 (has links)
Orientador: José Maurício Barbanti Duarte / Coorientador: Susana González / Banca: Alexandre Reis Percequillo / Banca: Renata Alonso Miotto / Banca: Eduardo Andrade Botelho de Almeida / Banca: Jesus Aparecido Ferro / Resumo: Considerada a espécie de cervídeo brasileira mais ameaçada de extinção, Mazama bororo, foi recentemente descrita em 1996. Devido a isso, aspectos básicos de sua biologia ainda são desconhecidos. Dessa maneira, o presente trabalho teve como objetivo utilizar DNA extraído de espécimes recentes e de museus para descrever a sua distribuição histórica, investigar a existência de padrões filogeográficos, avaliar a taxonomia da espécie e os erros de identificação no material analisado pertencente aos acervos científicos de museus. Para tanto, foi realizada a extração de DNA de 200 amostras de ossos turbinais obtidos em museus de história natural e 78 destes espécimes foram identificados a partir de iniciadores do gene citocromo b (224bp). O total de 22 espécimes identificados como pertencentes à espécie Mazama bororo permitiu conhecer áreas inéditas da distribuição histórica e, possivelmente atuais, da espécie, como os estados de Rio Grande do Sul, Minas Gerais, Goiás, Espírito Santo e Bahia. Além disso, a comparação entre o DNA dos holótipos de Mazama bororo e de Mazama americana jucunda indica que a espécie M. bororo corresponde à subespécie M. americana jucunda, descrita em 1913, demonstrando a necessidade de elevar essa subespécie à categoria de espécie. Análises filogeográficas da espécie demonstram que M. bororo não apresenta uma estruturação populacional histórica e que diversidade genética é baixa quando comparada a outras espécies, um indicativo de que políticas de manutenç... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Mazama bororo was recently described in 1996 and is considered the most threatened species of Brazilian deer. Due to this, basic aspects of its biology are still unknown. Thus, this research project aims to use DNA extracted from recent specimens and from natural history collections to review the taxonomy, to describe historical distribution and to investigate the existence of phylogeographic patterns on M. bororo. For this purpose, we extracted DNA from 200 samples of turbinate bones obtained from natural history collections and 78 of these were identified from cytochrome b initiator (224bp). We obtained a total of 22 specimens identified as M. bororo. This result allowed identify unpublished areas on historical and perhaps current distribution of M. bororo in states such as Rio Grande do Sul, Minas Gerais, Goiás, Espírito Santo and Bahia. Moreover, the comparison among the DNA from holotype of M. bororo and Mazama americana jucunda indicates that M. bororo corresponds to the subspecies M. americana jucunda, described in 1913, highlighting the need to raise this subspecies to full species status. Our results also demonstrates that M. bororo did not show a genetic structuration of their populations and that their genetic diversity is lower than other species, highlighting the need to increase conservation and environment policy efforts to maintenance of this species. Finally, when we compare the morphological identification available on natural history collections with the identification obtained from molecular markers we found that the error rate resulting from the classification based on morphological characters was 26%. Nevertheless, we expect with the help of DNA from natural history collections will be possible to select non-convergent morphological characters for this group, allowing thus correct morphological identifications ... (Complete abstract click electronic access below) / Doutor
|
Page generated in 0.1153 seconds