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Articles 1 - 12 of 12
Full-Text Articles in Genetics and Genomics
The Influence Of Environmental Change On Genetic Diversity Across Spatial And Taxonomic Scales, Connor M. French
The Influence Of Environmental Change On Genetic Diversity Across Spatial And Taxonomic Scales, Connor M. French
Dissertations, Theses, and Capstone Projects
The spatial distribution of genetic diversity is of interest to biodiversity scientists and conservationists and is a fundamental metric of biodiversity. Genetic diversity patterns across spatial and taxonomic scales contain information about population and assemblage dynamics that can convey their resilience to environmental change. Ectotherms are especially linked to their environments and may be especially sensitive to fluctuations in the environment over time. Herein, I investigate global and regional patterns of genetic diversity in two groups of ectotherms, insects and lizards, to understand the relationship between environmental change and genetic diversity, from populations to assemblages. Overall, my research aims to …
Population Genomics, Ecology And Conservation Of Asterias Sea Stars In The North Atlantic, Melenia I. Giakoumis
Population Genomics, Ecology And Conservation Of Asterias Sea Stars In The North Atlantic, Melenia I. Giakoumis
Dissertations, Theses, and Capstone Projects
Uncovering how species respond to environmental change is a central question in biology (Ehrlén & Morris 2015; Habibullah et al. 2022). It is the key to elucidating the past, understanding the present and predicting the future of species’ population dynamics. This dissertation investigates the influence of environmental change on intertidal species’ distributions and genomics at several timescales, with implications for conservation.
Environmental changes have occurred throughout history, on a geological scale, and have shaped the global patterns of species’ distributions and population sizes. Biologists have long studied how geological history has shaped species distributions (Sanmartín 2012) in both terrestrial (Liu …
Genomic Insights Into Mechanisms Of Microbial Evolution And Evolution-Inspired Strategies To Combat Pathogen Diversity, Saymon Akther
Genomic Insights Into Mechanisms Of Microbial Evolution And Evolution-Inspired Strategies To Combat Pathogen Diversity, Saymon Akther
Dissertations, Theses, and Capstone Projects
We live in an era of emerging infectious diseases that are increasingly common, rapidly spreading, and gravely devastating. Lyme disease, caused by bacteria belonging to the genus Borreliella, is rapidly rising in the Northern Hemisphere because of geographic range expansion of both the tick vectors and the pathogens. Evolutionary comparative analysis of Borreliella genomes is a key to understanding the phylogeographic history and mechanisms of their global diversification. Moreover, genomic variations in Borreliella associated with human pathogenicity, e.g., at loci encoding cell-surface antigens interacting with the vertebrate hosts, have not been fully identified. Similarly, the ongoing COVID-19 pandemic, caused …
Genomic And Ecological Dimensions Of Malagasy Reptile And Amphibian Biodiversity, Arianna L. Kuhn
Genomic And Ecological Dimensions Of Malagasy Reptile And Amphibian Biodiversity, Arianna L. Kuhn
Dissertations, Theses, and Capstone Projects
A long history of isolation coupled with complex topographic and ecological landscapes makes Madagascar ideal for exploring the historical factors that have shaped patterns of population diversity and endemism. Many species-level studies have suggested Late Quaternary climate change may have influenced population dynamics in the tropics, but Madagascar’s ecologically unique biomes or individual species properties may have driven idiosyncratic responses to these shifts. Using community-scale population genetic data I implement a hierarchical approximate Bayesian computation (hABC) approach to evaluate the degree of synchronous population expansion during glacial cycles across herpetofaunal assemblages both within and across discrete biomes and taxonomic groups. …
On The Distribution Of Genetic Variation In Ecological Communities, Isaac Overcast
On The Distribution Of Genetic Variation In Ecological Communities, Isaac Overcast
Dissertations, Theses, and Capstone Projects
Biodiversity in ecological communities is structured hierarchically across spatial and temporal scales. Many open questions remain as to how this structure accumulates. For example, what are the relative contributions of dispersal versus in situ speciation? Or, how important are stochastic drift versus deterministic processes? Up to this point, these questions have been investigated by isolated disciplines (e.g. macroecology, comparative phylogeography, macroevolution) using tools and data that tend to focus on only one axis of community scale data (e.g. phylogenies, relative abundances, and/or trait information). Yet we know that there are feedbacks among processes that respond on short, medium, and long …
A Contribution Toward A Global Monograph Of Gyroporus: Taxonomy, Phylogeny, Biogeography, Naveed Davoodian
A Contribution Toward A Global Monograph Of Gyroporus: Taxonomy, Phylogeny, Biogeography, Naveed Davoodian
Dissertations, Theses, and Capstone Projects
Gyroporus (Sclerodermatineae, Boletales, Agaricomycetes, Basidiomycota, Fungi) is a genus of ectomycorrhizal mushroom-forming fungi distributed throughout the world in suitable habitats. Previous attempts to untangle the diversity of this genus proved difficult due to the presence of semi-cryptic species and equivocal results from phylogenetic analysis of ribosomal RNA markers. To overcome these obstacles, a combined taxonomic and phylogenetic (emphasizing protein-coding genes) approach is used here to delimit species and elucidate geographic and evolutionary patterns of Gyroporus. Careful study of relevant literature and herbarium specimens was augmented by field work in North America, Australia, and East Asia for observation and collection …
Using Molecular Markers To Trace The Population History Of Volant Organisms At Differing Temporal Scales, Noah A. Burg
Using Molecular Markers To Trace The Population History Of Volant Organisms At Differing Temporal Scales, Noah A. Burg
Dissertations, Theses, and Capstone Projects
Using molecular markers to test phylogenetic and phylogeographic hypotheses is critical for tracking the population origin of invasive, introduced species (Chapter 2, Chapter 4) and to identify the systematic relationships of disparate lineages at both shallow and deep evolutionary time scales (Chapters 3, Chapter 4). In this thesis, Sanger Sequencing was used to generate datasets based on fresh and preserved tissue from specimens collected in the field, as well as museum tissue vouchers granted from various institutions in the US and Europe. In combining these source materials, data were generated for three focal studies: 1) In the first research section …
Convergent Evolution Of Biochemical Innovations In Polychaetes: Characterizing The Molecular Basis Of Bioluminescence And Venom Production, Aida E. Verdes Gorín
Convergent Evolution Of Biochemical Innovations In Polychaetes: Characterizing The Molecular Basis Of Bioluminescence And Venom Production, Aida E. Verdes Gorín
Dissertations, Theses, and Capstone Projects
The convergent evolution of phenotypic traits is a widespread phenomenon across the tree of life and is explained as the outcome of different taxa facing similar selective forces or environmental conditions. A longstanding question in evolutionary biology is whether the evolution of convergent phenotypes in unrelated lineages is driven by similar or different molecular processes. The research presented here investigates this question by characterizing the molecular basis of two biochemical innovations, bioluminescence and venom production, that have evolved independently in different lineages of polychaetes worms (Annelida). We use an integrative approach, combining next-generation sequencing, phylogenetics and computational tools to evaluate …
Comparative Phylogeographic, Population Genomic, And Selection Inference With Development Of Hierarchical Co-Demographic Models, Alexander Xue
Comparative Phylogeographic, Population Genomic, And Selection Inference With Development Of Hierarchical Co-Demographic Models, Alexander Xue
Dissertations, Theses, and Capstone Projects
Comparing demographic histories across assemblages of populations, species, and sister pairs has been a focus in phylogeography since its inception. Initial approaches utilized organelle genetic data and involved qualitative comparisons of genetic patterns for evaluating hypotheses of shared evolutionary responses to past environmental changes. This endeavor has progressed with coalescent model-based statistical techniques and advances in next-generation sequencing, yet there remains a need for methods that can analyze aggregated genomic-scale data from non-model organisms within a unified framework that considers individual taxon uncertainty and variance. To this end, the aggregate site frequency spectrum (aSFS), an expansion of the site frequency …
Phylogeny, Systematics And Biogeography Of Short-Tailed Opossums (Didelphidae: Monodelphis), Silvia E. Pavan
Phylogeny, Systematics And Biogeography Of Short-Tailed Opossums (Didelphidae: Monodelphis), Silvia E. Pavan
Dissertations, Theses, and Capstone Projects
Short-tailed opossums (genus Monodelphis) comprise the most species-rich genus of New World marsupials, with 25 currently recognized species. Monodelphis comprise small, terrestrial species collectively widespread in South America, which makes the group potentially informative about biogeographic processes that have shaped the continental fauna. The genus exhibits striking variation in several phenotypic characters, notably pelage coloration, behavior, and reproductive strategies. This diversity is unique among Neotropical marsupials, and makes the group particularly interesting to investigate the evolution and the adaptive significance of phenotypic trait variation. Despite this potential, missing knowledge on phylogeny and basic taxonomy precludes broader studies on evolution …
Comparative Population Genomics And Speciation Of Snakes Across The North American Deserts, Edward A. Myers
Comparative Population Genomics And Speciation Of Snakes Across The North American Deserts, Edward A. Myers
Dissertations, Theses, and Capstone Projects
Understanding the process of speciation is of central interest to evolutionary biologists. Speciation can be studied using a phylogeographic approach, by identifying regions that promote lineage divergence, addressing whether speciation has occurred with gene flow, and when extended to multiple taxa, addressing if the same patterns of speciation are shared across codistributed groups with different ecologies. Here I examine the comparative phylogeographic histories and population genomics of thirteen snake taxa that are widely distributed and co-occur across the arid southwest of North America. I first quantify the degree to which these species groups have a shared history of population divergence …
The Evolution Of The Viral Rna Sensor Oas1 In Old World Monkeys And Cetartiodactyls, Ian Fish
The Evolution Of The Viral Rna Sensor Oas1 In Old World Monkeys And Cetartiodactyls, Ian Fish
Dissertations, Theses, and Capstone Projects
Animals produce an array of sensors patrolling the intracellular environment poised to detect and respond to viral infection. The oligoadenylate synthetase family of enzymes comprises a crucial part of this innate immune response, directly signaling endonuclease activity responsible for inhibiting viral replication. Oligoadenylate synthetase 1 plays a vital role in animal susceptibility to pathogens including flaviviruses such as dengue, West Nile, and hepatitis c virus. This thesis includes a population level analysis of OAS1 diversity within macaque and baboon species followed by a broader survey of the gene in nineteen Old World monkeys. My research found that at the species …