Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 117 for “"Phylogenetic trees"”.
-
MINING SARS-COV-2 PHYLOGENETIC TREES TO ESTIMATE CIRCULATING INFECTIONS AND PATTERNS OF MIGRATION
The SARS-CoV-2 pandemic led to the formation of very large databases of genomic viral data. These databases contain information on transmission dynamics, emergence and evolution of SARS-CoV-2. However, extracting this information from sequences is difficult, as most methods of analyzing viral …
-
Enumeration Results On Leaf Labeled Trees
<p>ENUMERATION RESULTS ON LEAF LABELED TREES,Virginia P. Johnson In evolutionary biology, it is common practice to represent the evolution of species, populations, and organisms with graphs, called phylogenetic or species trees. These are rooted leaf-labeled trees where non-root internal vertices …
-
From trees to networks and back
… of a set of species is commonly represented by a phylogenetic tree. Often, however, the data contain conflicting signals, which can be better represented by a more general structure, namely a phylogenetic network. Such networks allow the display of several alternative evolutionary scenarios …
-
Assessment of species boundaries of the Moringa Ovalifolia (Dinter & A. Berger) in Namibia using nuclear its DNA sequence data
… Moringa comprises of thirteen (13) species of trees and shrubs, widely distributed in the tropical and subtropical regions. For its size, this genus is one of the phenotypically varied group of angiosperms whose members are mostly sought after for nutritional, nutraceutical and industrial uses. …
-
Phylogenetic Tree Inferences Using Quartet Splits
<p>Phylogenetic trees are used by evolutionary biologists and geneticists as a way of classifying the relationships between different taxonomic units (i.e. species, subspecies, genes). The branching of a tree represents one taxonomic unit evolving into two or more different units. These events are …
-
Bayesian phylogenetic models for relaxed clock and trait evolution
… Carlo (MCMC) has become a common approach for phylogenetic inference. While huge amount of data provides signi cant information of evolution, phylogenetic inference of larger data sets requires more e cient MCMC methods. In the meantime, it remains challenging to estimate phylogenetic trees …
-
Presentations of Semigroup Algebras of Weighted Trees
… algebras of binary symmetric models of phylogenetic trees studied by Buczynska and Wisniewski. These algebras arise as toric degenerations of projective coordinate rings of weight varieties of the Grassmannian of two planes associated to the Pl\"ucker embedding, and as toric …
-
Analysis of the impact on phylogenetic inference of non-reversible nucleotide substitution models
Most phylogenetic trees are inferred using time-reversible evolutionary models that assume that the relative rates of substitution for any given pair of nucleotides are the same regardless of the direction of the substitutions. However, there is no reason to assume that the underlying biochemical …
-
Exploring the boundaries of shallow phylogeny in the YESS group and the dynamics of gene cluster and operon formation in bacterial genomes
… different approaches such as the use of 16S rRNA phylogenetic trees, phylogenetic supertrees and concatenation of individual genes in order to construct phylogenetic trees compare with one another. What effect will problems associated with resolving shallow-phylogeny have on recovering a tree of …
-
Predicting Mutational Pathways of Influenza A H1N1 Virus using Q-learning
… its evolutionary patterns. Current research uses phylogenetic trees as the basis to guide population genetics and other phenotypic characteristics when describing the evolution of the influenza genome. Phylogenetic trees are one form of representing the evolutionary trends of sequenced genomes, …
-
Phylogenetic Relationships of Thermophilic Bacteria
… eubacteria and the archaebacteria. The phylogenetic relationships of several new isolates of extremely thermophilic bacteria have been determined and used to gain a deeper understanding of the role of thermophilic bacteria in early evolution. The 16S and 23S ribosomal RNA genes from the …
-
A deeper look into the morphology and receptors found in the tick (Acari: Ixodidae) chemoperception structure, the Haller's organ
… of male and female ticks. Additionally, two phylogenetic trees were created corresponding to each receptor type. The phylogenetic trees show the orthology between the tick ionotropic and gustatory receptors and the described insect chemoreceptors. There were two I. scapularis IRs expressed in …
-
Sampled ancestors and dating in Bayesian phylogenetics
This thesis introduces sampled ancestor phylogenetic trees—trees in which sampled taxa can lie directly on the branches and represent ancestors of other taxa that are sampled later. Phylogenetic trees in molecular biology were traditionally reconstructed from molecular data of contemporaneous …
-
Graph-Based Computational Approaches for Modeling Viral Evolution
… and the scale of modern genomic data. Most phylogenetic trees enforce a strictly bifurcating structure that struggles to represent recurrent mutations, recombination, convergent evolution, and intra-host diversity. In contrast, quasispecies theory describes viral populations as clouds of …
-
Investigations of the Accuracy of Partial Genome Sequencing and Restriction Fragment Analysis in Determination of Genetic Relationships: A Computer Simulation Study
… of genetic relationships, as represented in phylogenetic trees. Three partial genome DNA sequences with different lengths (200, 600, 1000 bps) and three analytic algorithms for restriction fragment data (the Dice coefficient, the Nei and Li distance, and the Weigel and Scherba distance) were …
-
Diversity and evolution of ecosystems: From genomes to the biosphere
… diversity in the genome, and the development of phylogenetic trees in evolution. The unifying theme is the interplay between ecology and evolution, expressed within an ecosystem, within genomes, and over the evolutionary history of life. Part I concerns biodiversity on the ecological scale. I …
-
Alignment- and Alignment-refining Algorithms: Effects on Branch-length Estimation and Selection Pattern Analyses
… of the effects of multiple-alignment method on phylogenetic analyses. First, I investigated the effects of multiple-sequence alignment quality on branch-length estimation, which can influence downstream bioinformatic analyses such as estimating rates of evolution and divergence times. To …
-
The primary structures and the evolutionary consequences of the olisthodiscus luteus histone proteins
… HO1 (Rizzo et al., 1985). Construction of phylogenetic trees suggests that the alga Olisthodiscus luteus diverged from the animal line. By sequence comparison, the most closely related histone sequence to the algae was found to be that of the echinodermata. An endosymbiotic event between an …
-
Phylogenetic Relationships within Coleeae (Bignoniaceae Juss.)
… The purpose of this study was to explore the phylogenetic relationships within Coleeae. In order to do so, techniques such as PCR by using universal primers for waxy nuclear gene, agarose electrophoresis, cloning and sequencing were performed. A total of 26 taxa were successfully amplified. …
-
Markov chain Monte Carlo and its applications to phylogenetic tree construction
… application of Bayesian methods to problems in phylogenetics. Specifically, we focus on using genetic data to estimate phylogenetic trees representing the evolutionary history of genes and species. Knowledge of this common ancestry has implications for the identification of functions and …
Page 1 of 6