Evolution Commons^™

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. …

Dynamics Of Hybrid Zones At A Continental Scale, Bradley T. Martin

Graduate Theses and Dissertations

Hybridization has traditionally been viewed as a happenstance that negatively impacts populations, but is now recognized as an important evolutionary mechanism that can substantially impact the evolutionary trajectories of gene pools, influence adaptive capacity, and contravene or reinforce divergence. Physiographic processes are important drivers of dispersal, alternately funneling populations into isolation, promoting divergence, or facilitating secondary contact of diverged populations, increasing the potential for hybridization. In North America, glacial-interglacial cycles and geomorphological changes have provided a dynamic backdrop over the last two million years that promoted such oscillations of population contraction and expansion. These biogeographic processes have resulted in regional …

Zebrafish (Danio Rerio) Hoxb6: An Exploration Into The Divergence Of Genomic Dna Sequence And Gene Expression Across Teleost Fishes Post-Genome Duplication, Amber Lynn Rittgers, Pierre Le Pabic, Adam Davis

Georgia Journal of Science

Hoxb6 is an evolutionarily conserved developmental regulatory gene that functions, in part, to pattern several organs and organ systems within the embryonic trunk during vertebrate embryogenesis. The cis-regulatory circuitry mediating trunk expression in mouse (Mus musculus) may be conserved across gnathostome vertebrates, as several other species show similar trunk expression patterns, including chicken (Gallus gallus), dogfish shark (Scyliorhinus canicula), and several teleost fishes. A whole genome duplication event that occurred in the lineage leading to teleost fishes has generated at least two Hoxb6 genes, hoxb6a and b6b. Two teleost fishes of the …

A Spatially Explicit Model Of Stabilizing Selection For Improving Phylogenetic Inference, Jeremy M. Beaulieu, Brian C. O'Meara, Michael A. Gilchrist

Biological Sciences Faculty Publications and Presentations

Ultraconserved elements (UCEs) are stretches of hundreds of nucleotides with highly conserved cores flanked by variable regions. Although the selective forces responsible for the preservation of UCEs are unknown, they are nonetheless believed to contain phylogenetically meaningful information from deep to shallow divergence events. Phylogenetic applications of UCEs assume the same degree of rate heterogeneity applies across the entire locus, including variable flanking regions. We present a Wright-Fisher model of selection on nucleotides (SeION) which includes the effects of mutation, drift, and spatially varying, stabilizing selection for an optimal nucleotide sequence. The SeION model assumes the strength of stabilizing selection …

Micro- And Macroevolution Of Drab Plumage Color In Birds, Rafael Marcondes

LSU Doctoral Dissertations

I address the evolution of drab bird colors at micro- and macroevolutionary scales. I use as a study system the Furnariida, a clade of >600 Neotropical passerine species that, despite tremendous ecological and morphological diversity, are colored almost exclusively in shades of brown and grey produced by melanin pigments.

In chapters two and three, I took a macroevolutionary approach and showed that (1) plumage colors in the Furnariida evolve at similar rates in a monochromatic clade, males of a dichromatic clade, and females of a dichromatic clade; (2) ventral plumage color evolves faster than dorsal; (3) bird species that occupy …

Single-Locus Species Delimitation And Ecological Niche Modeling Provide Insights Into The Evolution, Historical Distribution, And Taxonomy Of The Pacific Chorus Frogs, Robert C. Jadin, Sarah A. Orlofske, Tereza Jezkova, Christopher Blair

Publications and Research

The Pacific chorus frogs are a complex of three wide-ranging species (i.e. Hyliola hypochondriaca, Hyliola regilla, Hyliola sierra) whose current taxonomy remains unresolved. We conducted species delimitation analyses of these taxa using fragments of the cytochrome b and 12S–16S mtDNA genes to assess the species diversity. Importantly, we included samples from new locations throughout the range to better understand species distributions and identify potential contact zones among clades. Our analyses revealed three slightly parapatric but distinct species-level clades. Molecular dating revealed that these species began diverging in the Pleistocene c. 1.4 Mya with H. hypochondriaca and …

A Multispecies Perspective Into Dietary Genetic Adaptations And Ancient Migration In The Peruvian Andes, Kelsey Jorgensen

Wayne State University Dissertations

Successful adaptation to the high-elevation Andes would have required both cultural and biological adaptations by early human populations. These past adaptations continue to shape the evolutionary outcomes of both humans and non-human species today. A multispecies perspective was used to examine how humans and non-human creatures, specifically insects, were shaped by past human adaptations. This dissertation asked two primary questions: 1) Given the importance and evolutionary history of potato consumption in the Peruvian Andes, is a genetic adaptation to better digest potato starch detectable in present-day Peruvians? and 2) Using the Andean Potato Weevil (APW) phylogeny as a proxy, what …

Lepidopteran Granivory Reduces Seed Counts In A Rare Species Of Riparian Scour Prairies, Cheyenne Moore, Angela J. Mcdonnell, Scott Schuette, Christopher T. Martine

Faculty Journal Articles

In Pennsylvania Baptisia australis var. australis is found along only four waterways: the Allegheny River, Youghiogheny River, Clarion River, and Red Bank Creek. Because of its limited distribution and small number of extant populations, the species is considered state-threatened in Pennsylvania. In addition, the riparian prairie habitat that Pennsylvania Baptisia australis var. australis is restricted to is also in decline and considered vulnerable. Because of these conservation concerns, insights into the natural history of the taxon in the state is valuable and will inform conservation efforts. Field surveys and fruit collections along the Allegheny River and herbarium collections were used …

Initial And Advanced Stages Of Microbiota Establishment Within The Tsetse Fly, Miguel Eduardo Medina Munoz

Graduate Theses, Dissertations, and Problem Reports (ETD)

Symbiosis is a long-term physical association between two or more species, although little is known regarding its evolutionary origins, particularly at the genetic level. Tsetse flies are the vector of African trypanosomes, causative agents of Human and Animal African Trypanosomiases. Tsetse provide an ideal model for studying initial and advanced stages of symbiosis. Tsetse have a simple digestive tract microbiota primarily consisting of two bacteria; the ancient mutualist Wigglesworthia glossinidia and the recently acquired Sodalis glossinidius. This work presents a chronological study in evolutionary terms of the history of a microbial-insect association. First, I present concepts on symbiosis and …

The Evolution Of Technology, Kelly Cooper

Williams Honors College, Honors Research Projects

As per outlined by Dr. Quinn, this literature review will be a comprehensive review paper including an overview of current and previous research done in the field of Memetics. This will further include sifting through literature to hone in on a specific, new area of memetics Dr. Weeks is focused on, the evolutionary change of abiotic factors through purchasing. This is to be completed with the help of the library worshops designed to teach the skills necessary to undergo a literature review of this size. I will also participate in weekly reading groups to discuss papers and work closely with …

Comparative Conservation Genomics Of A Suite Of Imperiled Freshwater Mussels, Scott C. Meyer

College of Graduate Studies: Theses & Dissertations

Maintenance of genetic diversity is a critical component to the management and recovery of imperiled species. By ensuring that a species’ genetic diversity is maintained, issues like inbreeding depression and loss of local adaptation can be prevented. However, the genetic diversity of many species are not well-characterized, and the factors that influence a species’ genetic diversity are often not well understood. In the case of imperiled unionid freshwater mussels, it is important to conduct conservation genetic assessments to aid in their management and preserve genetic diversity. This is the first study to conduct a comparative conservation genomic assessment for eight …

Functional Genetic Approaches To Provide Evidence For The Role Of Toolkit Genes In The Evolution Of Complex Color Patterns In Drosophila Guttifera, Mujeeb Olushola Shittu

Dissertations, Master's Theses and Master's Reports

Toolkit genes are set of genes that orchestrate the development of basic body plan of animals, and they are highly conserved in all animals. The co-option of the toolkit genes into the pigmentation pathway has led to the evolution of novel species. This study focuses on understanding how the complex color patterns in animals develop by using the Drosophila species in the quinaria group as models. We developed an mRNA in situ hybridization (ISH) protocol, which allowed us to study gene expression patterns in the abdomen of developing pupae of non-model Drosophila species (Chapter 2). Through ISH, we found that …

Breaking The Chain – The Role Of Intersexual Genetic Correlations In Sexual Dimorphism And The Consequences And Limits Of Their Evolution, Matthew Ma Maoloni, Tara Newman, Tristan Af Long Dr.

Theses and Dissertations (Comprehensive)

In many sexually reproducing species, males and females often differ in countless ways beyond their primary sexual organs. This phenomenon is known as sexual dimorphism, and it is generally considered to be an adaptive response to differences in the selection pressures experienced by males and females. Despite the advantages associated with sexual dimorphism, it does not evolve completely unhindered – there are plenty of biological effects that can limit the extent and rate of divergence between the sexes. This research project focusses on the potential role of the intersexual genetic correlation (r_mf­) – which describes the …

A Cophylogenetic Analysis Of Fungus Gardening Ants And Their Symbiotic Fungi, Katherine Beigel

Biology Theses

Fungus-growing ants (Tribe Attini) and their fungal cultivars share a 50-million-year coevolutionary history. Large scale phylogenetic analyses depict a strong co-phyletic signal among ants and their farmed fungi yet fungus sharing among unrelated ant lineages is somewhat widespread. An overview of sharing has been hampered by a lack of genetic markers that exhibit intraspecific variation and surveys across geographic regions. For example, previous studies have shown similar sequences of the internal transcribed spacer (ITS) region of fungus in different species of Trachymyrmex, suggesting that these ant species are farming the same fungal clone. To examine whether this was a …

Quantifying Structure And Variation In Complex Phylogenetic Data, Genevieve Geraldine Mount

LSU Doctoral Dissertations

Identifying the source and structure of variation in nature is crucial to understanding fundamental aspects of evolution. Despite a recent plethora of genetic and morphological data, many interesting questions about the relationships between different groups remain unresolved. My dissertation evaluates three approaches for identifying and quantifying the variation within phylogenetic datasets. Characterizing variation within datasets and across analytical methods gives insight into biologically interesting characters, unusual evolutionary processes, and areas for model improvement.

Network-based community detection approaches offer a powerful tool to describe variation in phylogenetic signal across the genome (i.e., gene tree variation). In Chapter 2, I investigate the …

Analysis Of Genomic Sequence Data Reveals The Origin And Evolutionary Separation Of Hawaiian Hoary Bat Populations, Corinna A. Pinzari, Lin Kang, Pawel Michalak, Lars S. Jermiin, Donald K. Price, Frank J. Bonaccorso

Life Sciences Faculty Research

We examine the genetic history and population status of Hawaiian hoary bats (Lasiurus semotus), the most isolated bats on Earth, and their relationship to northern hoary bats (Lasiurus cinereus), through whole-genome analysis of single-nucleotide polymorphisms mapped to a de novo-assembled reference genome. Profiles of genomic diversity and divergence indicate that Hawaiian hoary bats are distinct from northern hoary bats, and form a monophyletic group, indicating a single ancestral colonization event 1.34 Ma, followed by substantial divergence between islands beginning 0.51 Ma. Phylogenetic analysis indicates Maui is central to the radiation across the archipelago, with the southward expansion to Hawai‘i and …

Structure And Evolution Of Lizard Immunity Genes, Trent Santonastaso

LSU New Orleans Theses and Dissertations

One of the most important gene families to play a role in adaptive immunity is the major histocompatibility complex (MHC). MHC class II loci are considered to be the most variable loci in the vertebrate genome, and studies have shown that this variability can be maintained through complex co-evolutionary dynamics between host and parasite. Despite the rich body of research into the MHC, there is comparatively little understanding of its genomic architecture in reptiles. Similarly, loci associated with innate immunity have received little attention in reptiles compared to other vertebrates. In the first chapter, we investigated the structure and organization …

Interrelationships Among Monorchiid Trematodes With Special Emphasis On Some Northwestern Atlantic Genera, Apryle Panyi

Master's Theses

The Monorchiidae Odhner, 1911 is a cosmopolitan family of flukes (Trematoda: Digenea) comprising species that parasitize the digestive tract of estuarine and marine fishes as adults. Compared with other oceans, recent morphological or molecular taxonomic work conducted on monorchiid species from the northwestern Atlantic Ocean has been sparse (Manter, 1931; Overstreet, 1969; Andres et al., 2018; Wee et al., 2018, 2019, 2020). Therefore, the present work investigated the interrelationships of some monorchiids from the northwestern Atlantic Ocean with emphasis on several genera and investigated if Lasiotocus minutus (Manter, 1931) Thomas, 1959 constitutes a complex of cryptic species. New morphological and …

The Evolution Of Bivalve Shell Matrix Proteins, Mark Ira Duhon Ii

LSU Doctoral Dissertations

This dissertation focuses on the molecular underpinnings surrounding the evolution of the biomineralized shells of marine bivalves. Bivalve molluscs synthesize remarkably complex shells from calcium carbonate and an organic matrix of proteins secreted from the dorsal edge of the mantle. Molecular analyses of shell matrix proteins (SMPs) have suggested high rates of gene turnover despite the conserved nature of the shell itself. Here, I used proteomic and transcriptomic data to identify the SMPs and other biomineralization proteins from seven bivalve species that diverged 3-513 Mya. Contrary to previous studies that identified only a few shared biomineralization transcripts across the Bivalvia, …

Statistical Inference Of Adaptation At Multiple Genomic Scales Using Supervised Classification And A Hidden Markov Model, Lauren A. Sugden

Biology and Medicine Through Mathematics Conference

No abstract provided.

A Genomic Analysis Of Bobcat Populations In North America With A Comparison To The Canada Lynx: An Assessment Of Local Adaptation To Unique Ecoregions And Phylogeography, Jennifer C. Broderick

Electronic Theses and Dissertations

Bobcats (Lynx rufus) are an ecologically and genetically diverse species with a large contiguous range throughout North America. The species not only has a wide array of phenotypic variation compared to other mammals, but shows marked adaptability across ecozones with differing ecological influences. It is these various selective pressures in distinctive parts of the continent that have likely led to localized adaptations within the bobcat metapopulations. The species is also marked by its ability to maintain connectivity and populations in anthropogenically developed areas, an advantage it has over other felids, including its close relative the Canada lynx ( …

Evolutionary Inference From Admixed Genomes: Implications Of Hybridization For Biodiversity Dynamics And Conservation, Tyler Chafin

Graduate Theses and Dissertations

Hybridization as a macroevolutionary mechanism has been historically underappreciated among vertebrate biologists. Yet, the advent and subsequent proliferation of next-generation sequencing methods has increasingly shown hybridization to be a pervasive agent influencing evolution in many branches of the Tree of Life (to include ancestral hominids). Despite this, the dynamics of hybridization with regards to speciation and extinction remain poorly understood. To this end, I here examine the role of hybridization in the context of historical divergence and contemporary decline of several threatened and endangered North American taxa, with the goal to illuminate implications of hybridization for promoting—or impeding—population persistence in …

A Deeper Meaning For Shallow-Level Phylogenomic Studies: Nested Anchored Hybrid Enrichment Offers Great Promise For Resolving The Tiger Moth Tree Of Life (Lepidoptera: Erebidae: Arctiinae), Nicolas J. Dowdy, Shannon Keating, Alan R. Lemmon, Emily M. Lemmon, William E. Conner, Clare H. Scott Chialvo, Susan Weller, Rebecca B. Simmons, Melissa S. Sisson, Jennifer M. Zaspel

Department of Entomology: Faculty Publications

Anchored hybrid enrichment (AHE) has emerged as a powerful tool for uncovering the evolutionary relationships within many taxonomic groups. AHE probe sets have been developed for a variety of insect groups, though none have yet been shown to be capable of simultaneously resolving deep and very shallow (e.g., intraspecific) divergences. In this study, we present NOC1, a new AHE probe set (730 loci) for Lepidoptera specialized for tiger moths and assess its ability to deliver phylogenetic utility at all taxonomic levels. We test the NOC1 probe set with 142 individuals from 116 species sampled from all the major lineages of …

Microrna Profiling In The Weddell Seal Suggests Novel Regulatory Mechanisms Contributing To Diving Adaptation, Luca Penso-Dolfin, Wilfried Haerty, Allyson Hindle, Federica Di Palma

Life Sciences Faculty Research

Background:The Weddell Seal (Leptonychotes weddelli) represents a remarkable example of adaptation to diving among marine mammals. This species is capable of diving... (See full abstract in article).

Evolutionary Ecology Of Host-Parasite Relationships: Role Of Host Ecology, Phylogeny, And Demographics In Shaping Parasite Evolution, Erika Taylor Gendron

Biology ETDs

Host-parasite systems exist across complex and ecologically heterogeneous landscapes, and may occur across taxonomically and ecologically disparate host species. Under these conditions, mechanisms underlying microevolutionary processes (i.e. gene flow, genetic drift) are not always clear, and may be mediated by numerous co-occurring factors specific to individual hosts. Host traits such as host immunology, demographics, phylogeny and ecology may act in concert to shape host-parasite relationships, and ultimately evolutionary processes. The research described herein used phylogeographic, phylogenomic, and population genetic methods to further understanding of how host traits impact the evolutionary ecology of trematode systems, using avian schistosomes (Digenea: Schistosomatidae) as …

Molecular Differentiation Of Astragalus Species And Varieties From The Western United States: The Chloroplast Dna Bridge Between Evolution And Molecular Systematics, Marwa Neyaz, Daniel Cook, Rebecca Creamer

Poisonous Plant Research (PPR)

Locoweeds are the most widespread poisonous plant problem in the world and have been reported in the Western United States since the 1800s, causing tremendous losses in livestock. Consumption of locoweeds by grazing animals stimulates the neurological disease, locoism, characterized by weight loss, ataxia, and lack of muscular coordination. The name locoweed is used for Astragalus and Oxytropis species known to contain swainsonine, the toxic principle produced by the plant endophytic fungus Undifilum. Astragalus includes 2,500-3,000 species and many varieties that have almost identical morphological characteristics that overlap among species, leading to improper identification. Therefore, the aim of this study …

Natural Variation And Evolutionary Responses To Climate Change Stressors In Marine Invertebrates, Joanna Sarah Griffiths

LSU Doctoral Dissertations

Our rapidly changing climate is putting many species at risk of extinction and there is an urgent need to understand how species will respond to these changes. In this dissertation, I evaluate how three species of marine invertebrates (corals, oysters, and copepods) respond to stressful conditions in their current environments and how plasticity and evolutionary adaptation could alter their response to future climate change stressors. I first employed a space for time study to elucidate population differences in the response of cold-water corals, Balanophyllia elegans, to future ocean acidification. I found evidence that upwelling history (natural low pH exposure) influences …

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 …

Gene Expression Pattern Analysis Of Anterior Hox Genes During Zebrafish (Danio Rerio) Embryonic Development Reveals Divergent Expression Patterns From Other Teleosts, Adam Davis

Georgia Journal of Science

The regional identity of organs and organ systems along the anterior-posterior axis during embryonic development is patterned, in part, by Hox genes, which encode transcription factor proteins that activate or repress the expression of downstream target genes. Divergent nested Hox gene expression patterns may have had a role in facilitating morphological divergence of structures, such as the pharyngeal jaw apparatus, among evolutionarily divergent teleost fishes. Recent studies from several evolutionarily divergent teleosts, such as the Japanese Medaka (Oryzias latipes) and the Nile Tilapia (Oreochromis niloticus), have shown the presence of divergent expression patterns of several Hox …

Temperate Eurasian Origins Of Hawaiian Chenopodium (Amaranthaceae) Plus Description Of A New Species Endemic To Moloka‘I, Jason T. Cantley, Angela J. Mcdonnell, J Branson, S R. Long, W Garnett, Christopher T. Martine

Faculty Journal Articles

Chenopodium taxa of Hawai‘i are tetraploids distinguished from other members of the circumglobally distributed genus by minute morphological characters. Because of these reasons, the geographic origin of Hawaiian Chenopodium has remained unclear. Across the Hawaiian Archipelago, Chenopodium taxa are morphologically variable and grow in highly disparate xeric habitats, especially in terms of precipitation, temperature, wind, salt spray, and solar irradiation. Habitats include dry subalpine shrublands, sandy beach strand of atolls in the Northwest Hawaiian Islands, dry forests, and precipitously tall sea cliffs of northwestern Moloka‘i. From the Moloka‘i sea cliffs, which are battered by high energy winds, salt spray, and …