Life Sciences Commons^™

Effects Of Spatial And Temporal Heterogeneity On The Genetic Diversity Of The Alpine Butterfly Parnassius Smintheus, Mel Lucas

Electronic Thesis and Dissertation Repository

Genetic diversity represents a population’s evolutionary potential, as well as its demographic and evolutionary history. Advances in DNA sequencing have allowed the development of new and potentially powerful methods to quantify this diversity. However, when using these methods best practices for sampling populations and analyzing data are still being developed. Furthermore, while effects of the landscape on spatial patterns of genetic variation have received considerable attention, we have a poorer understanding of how genetic diversity changes as a result of temporal variation in environmental and demographic variables. Here, I take advantage of advances in DNA sequencing to investigate genetic diversity …

Cross-Species Utility Of The Mouse Diversity Genotyping Array In Assaying Single Nucleotide Polymorphisms, Rachel Kelly

Electronic Thesis and Dissertation Repository

In the study of genetic diversity in non-model species there is a notable lack of the low-cost, high resolution tools that are readily available for model organisms. Genotyping microarray technology for model organisms is well-developed, affordable, and potentially adaptable for cross-species hybridization. The Mouse Diversity Genotyping Array (MDGA), a single nucleotide polymorphism (SNP) genotyping tool designed for M. musculus, was tested as a tool to survey genomic diversity of wild species for inter-order, inter-family, inter-genus, and intra-genus comparisons. Application of the MDGA cross-species provides genetic distance information that reflects known taxonomic relationships reported previously between non-model species, but there …

Spatial And Temporal Patterns Of Neutral And Adaptive Genetic Variation In The Alpine Butterfly, Parnassius Smintheus, Maryam Jangjoo

Electronic Thesis and Dissertation Repository

Understanding how much genetic diversity exists in populations, and the processes that maintain that diversity, has been a central focus of population genetics. The evolutionary processes that determine patterns of genetic diversity depend on underlying ecological processes such as dispersal and changes in population size. In this thesis, I examine the influence of dispersal and population dynamics on neutral and adaptive genetic variation in a naturally occurring network of populations of the alpine butterfly, Parnassius smintheus.

My first objective was to determine the combined consequences of demographic bottlenecks and dispersal on neutral genetic variation within and among populations. Using …

Understanding The Impact Of Hiv-1 Genetic Diversity On The Function Of Nef And Its Role In Serinc5 Antagonism, Aaron Leslie Johnson

Electronic Thesis and Dissertation Repository

HIV-1 Nef is a key pathogenic protein, allowing HIV-1 to evade the host immune system by downregulating MHC-I and CD4. Furthermore, it was recently discovered that Nef counteracts the host factor SERINC5 to increase HIV-1 infectivity, but the mechanistic details of the Nef:SERINC5 interaction still need to be explored. Throughout this dissertation, I will explore the hypothesis that the genetic diversity that defines HIV-1 has a pronounced effect on the HIV-1 protein Nef, altering its function between and within group M subtypes. To address this hypothesis I investigated how MHC-I and CD4 downregulation differ among all non-recombinant group M subtypes. …

The Major Histocompatibility Complex In Song Sparrows: Immunity, Signals, And Mate Choice, Joel W.G. Slade

Electronic Thesis and Dissertation Repository

In recent years, sexual selection theory has redefined genetic quality to consider not only additive genetic effects on fitness but also non-additive genetic effects, such as heterozygote advantage or disadvantage. In jawed vertebrates, the major histocompatibility complex (MHC) gene family has been shown to exhibit both additive and non-additive genetic effects on fitness. MHC gene products are involved in initiating adaptive immune responses, and MHC genotype determines the range of pathogens to which an individual can respond. Therefore, parasite-mediated selection at MHC may favour locally-adapted, rare, or particular combination of alleles. Because heterozygote advantage at MHC is widespread, sexual selection …

Evolutionary Genetic Aspects Of Host Association In Generalist Ectoparasites, Benoit Talbot

Electronic Thesis and Dissertation Repository

Despite the use of the host for dispersal by most parasite species, the extremely loose relationship typical between highly mobile hosts and generalist ectoparasites may lead to very different gene flow patterns between the two, leading in turn to different spatial genetic structure, and potentially different demographic history. I examined how similar gene flow patterns are between Cimex adjunctus, a generalist ectoparasite of bats present throughout North America, and two of its key bat hosts. I first analyzed the continent-scale genetic structure and demographic history of C. adjunctus and compared it to that of two of its hosts, the …

Mhc Class Iiβ Diversity As A Correlate Of Neutral-Locus Similarity And Diversity, And A Predictor Of Overwinter Return, In Song Sparrows (Melospiza Melodia), Matthew J. Watson

Electronic Thesis and Dissertation Repository

Abstract

The major histocompatibility complex (MHC) is a family of genes involved with recognizing pathogens and mounting an immune response. Parasite-mediated selection often favours heterozygosity at MHC because MHC-diverse individuals recognize a wider range of pathogens. Because migratory birds encounter many pathogens, I hypothesized that MHC diversity predicts overwinter and juvenile survivorship in song sparrows (Melospiza melodia). I found no correlation between MHC diversity and neutral-locus (microsatellite) heterozygosity, suggesting that measures of neutral and adaptive genetic diversity provide complementary rather than redundant information. However, pairwise similarity at MHC predicted pairwise similarity at microsatellite loci. In contrast to my hypothesis, MHC …

Genetic And Morphological Variation Of Butterflies In Relict Habitats, Lindsay A. Crawford

Electronic Thesis and Dissertation Repository

Habitat fragmentation and loss are leading threats to global biodiversity and can alter patterns of dispersal, population dynamics, and genetics with implications for long-term species persistence. Most habitat fragmentation research has focused on recently fragmented species that historically occupied interconnected habitat patches. We know comparatively little about how naturally fragmented species may respond to habitat loss. For these species, local habitat patch quality may influence the dynamics and genetics of populations more than the structure of the surrounding landscape (e.g., degree of isolation of suitable habitat). I examined aspects of the ecology and evolution of populations inhabiting fragmented landscapes, using …

The Plastic And Evolutionary Responses Of Fish To Anthropogenic Stressors, Ross D. Breckels

Electronic Thesis and Dissertation Repository

Ecosystems are being altered at unprecedented rates with little knowledge of the potential impacts on biodiversity. Two of the most pressing contemporary anthropogenic stressors are pollution and global warming. Species can respond to these stressors via dispersal, phenotypic plasticity, or evolutionary adaptation. Many species, especially aquatic organisms, experience ecological or physical barriers to dispersal and will therefore have to respond via phenotypic plasticity or evolutionary responses. I examined the responses of multiple traits associated with fitness in fish to pollution and increased temperature using a 2 × 2 common garden experimental design. I examined the effects of pollution on behaviour …

The Relationship Between Predation Pressure, Demography And Genetic Diversity In Song Sparrow (Melospiza Melodia) Populations, Michelle E. Bondy

Electronic Thesis and Dissertation Repository

While the impacts of predators on prey demography are well studied, relatively few studies have explored how predators affect the population genetics of prey. I investigated the effects of predation pressure on genetic diversity and genetic similarity in song sparrows (Melospiza melodia) and the demographic mechanisms (births, deaths and dispersal) that may drive this relationship. I compared genetic diversity and genetic similarity (measured at 13 neutral microsatellite loci) between landscapes (island and mainland), and between populations within each landscape. In every comparison, sparrows inhabiting the landscape or population with higher nest predation were more related to one another, and …