Evolution Commons^™

Evolution In Action: Climate Change, Biodiversity Dynamics And Emerging Infectious Disease, Eric P. Hoberg, Daniel R. Brooks

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host–parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly …

Genetically Based Low Oxygen Affinities Of Felid Hemoglobins: Lack Of Biochemical Adaptation To High-Altitude Hypoxia In The Snow Leopard, Jan E. Janecka, Simone S. E. Nielsen, Sidsel D. Andersen, Federico G. Hoffmann, Roy E. Weber, Trevor Anderson, Jay F. Storz, Angela Fago

School of Biological Sciences: Faculty Publications

Genetically based modifications of hemoglobin (Hb) function that increase blood–O₂ affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O₂ affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood–O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, …

The Evolution Of Sex Determination And The Dmrt1 Gene In The Japanese Gecko (Gekko Japonicus), Lisa-Marie Mullen

All Master's Theses

There are different sex-determining mechanisms in our environment, which are separated into two groups known as genotypic sex determination (GSD) and environmental sex determination. The most well-known mechanism in the ESD group is temperature-dependent sex determination (TSD). In this study, the presence of the Doublesex and mab-3-related Transcription Factor (Dmrt1) gene was observed during embryonic development in geckos with a TSD mechanism. To do this, I observed the rate of transcription of the Dmrt1 gene in the Gecko species Gekko japonicus. Pregnant geckos were caught around Nanjing, China. Once the females laid their eggs, the eggs were …

Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims

College of Graduate Studies: Theses & Dissertations

Nonstructural carbohydrates (NSC) can supply substrate during periods when current photosynthate is unavailable or inadequate to meet metabolic demands. I hypothesized that natural selection has favored higher nonstructural carbohydrate concentrations ([NSC]) in species that have an evolutionary history of frequent disturbance and tested this using three southern pine species that have evolved under a continuum of disturbance frequencies (evolutionary history of fire ~ longleaf > slash > loblolly). Stem and root samples were collected from 12 similar-sized individual trees of each species during time periods that reflect the annual minimum and maximum [NSC]. A modified colorimetric method was performed on the samples …

Behavioral Responses Of Male Parasitic Wasps To Plant Cues: A Comparison Of Two Host-Plant Complex Sources Of Cotesia Congregata (Say), Megan Ayers

Theses and Dissertations

Prior exposure to plants cues can enhance assortative mating in insects. We hypothesized that, as previously reported for females, males of Cotesia congregata would display inherent responses to plant cues that could be modified by postemergence experience and further, that males originating from two different host-plant complexes (HPCs) would display different behavioral responses to these HPCs. In no-choice contact assays with a non-host plant, searching responses of males and females increased sharply at Day 2 and remained stable through Day 4. In no-choice assays with potential host plants, males searched longer on catalpa than tobacco; responses were not modified by …

Genetic And Environmental Variation In Condition, Cutaneous Immunity, And Haematocrit In House Wrens, Scott K. Sakaluk, Laura A. Vogel, Alastair J. Wilson, E. Keith Bowers, L. Scott Johnson, Brian S. Masters, Bonnie Gp Johnson, Anna M. Forsman, Charles F. Thompson

Faculty Publications – Biological Sciences

Background

Life-history studies of wild bird populations often focus on the relationship between an individual’s condition and its capacity to mount an immune response, as measured by a commonly-employed assay of cutaneous immunity, the PHA skin test. In addition, haematocrit, the packed cell volume in relation to total blood volume, is often measured as an indicator of physiological performance. A multi-year study of a wild population of house wrens has recently revealed that those exhibiting the highest condition and strongest PHA responses as nestlings are most likely to be recruited to the breeding population and to breed through two years …

Characterization Of The Transcriptome, Nucleotide Sequence Polymorphism, And Natural Selection In The Desert Adapted Mouse Peromyscus Eremicus, Matthew D. Macmanes, Michael B. Eisen

Molecular, Cellular & Biomedical Sciences

As a direct result of intense heat and aridity, deserts are thought to be among the most harsh of environments, particularly for their mammalian inhabitants. Given that osmoregulation can be challenging for these animals, with failure resulting in death, strong selection should be observed on genes related to the maintenance of water and solute balance. One such animal, Peromyscus eremicus, is native to the desert regions of the southwest United States and may live its entire life without oral fluid intake. As a first step toward understanding the genetics that underlie this phenotype, we present a characterization of the …

A Molecular Framework Phylogeny For Ptilotus (Amaranthaceae), Timothy A. Hammer

Biological Sciences Theses & Dissertations

Ptilotus (Amaranthaceae) is an Australian genus with over 100 species, most of which occur in arid Western Australia. Ptilotus has been a taxonomically difficult genus; despite rigorous morphological studies into the genus over many years, previous workers have found it difficult to delimit infrageneric groups due to inconsistent morphological variation. With the goal to establish a phylogenetic framework for the genus, 100 taxa were sampled, including 87 Ptilotus spp., and the ITS nrDNA and matK cpDNA were sequenced. The phylogeny was reconstructed using Bayesian, maximum likelihood and maximum parsimony analyses on separate and concatenated datasets. Morphological characters were assessed and …

Ecological Niches, Species Distributions, And Biogeographic Processes In Rodents On Neotropical Sky Islands, Mariano Soley

Dissertations, Theses, and Capstone Projects

This dissertation focused on the methodological and theoretical improvement of correlative ecological niche models (ENMs) to better understand the processes governing species distributions and associated evolutionary divergence in rodents inhabiting mesic conditions in the Neotropics. Focusing on a widespread rodent from northern South America (Heteromys anomalus), in the first chapter I proposed and tested a methodological approach to surmount the challenge of incorporating environmental information from the margins of species geographic ranges into ENMs. In so doing, I argue how populations that exist on the borders of species' local ranges (spatial margins) can lead to exaggerated estimates of their niches …

Acceptance Of Evolution By America’S Educators Of Prospective Teachers, Guillermo Paz-Y-Miño-C, Avelina Espinosa

New England Science Public: Series Evolution

Paz-y-Miño-C G & Espinosa A. 2014. Acceptance of Evolution by America’s Educators of Prospective Teachers. New England Science Public: Series Evolution 2(1): 1-92 (ISSN: 2326-0971). In NESP Series Evolution Vol 2 No 1, Paz-y-Miño-C and Espinosa use the conceptual framework of the Incompatibility Hypothesis (i.e. science/evolution and belief in supernatural causation are incompatible) to document the patterns of acceptance of evolution of 495 Educators of Prospective Teachers affiliated with 281 colleges and universities widely distributed in 4 regions, 9 divisions, and 50 states in the United States. These higher-education professionals (65% PhD-, 22% doctorate-holders) were polled in five areas: (i) …

A Homogenizing Process Of Selection Has Maintained An 'Ultra-Slow' Acetylation Nat2 Variant In Humans, Blandine Patillon, Pierre Luisi, Estella S. Poloni, Sotiria Boukouvala, Pierre Darlu, E. Genin, Audrey Sabbagh

Human Biology Open Access Pre-Prints

N-acetyltransferase 2 (NAT2) is an important enzyme involved in the metabolism of a wide spectrum of naturally occurring xenobiotics, including therapeutic drugs and common environmental carcinogens. Extensive polymorphism in NAT2 gives rise to a wide interindividual variation in acetylation capacity which influences individual susceptibility to various drug-induced adverse reactions and cancers. Striking patterns of geographic differentiation have been described for the main slow acetylation variants of the NAT2 gene, suggesting the action of natural selection at this locus. In the present study, we took advantage of the whole-genome sequence data available from the 1000 Genomes project to investigate the …

Phylogenetics And Mating System Evolution In The Southern South American Valeriana (Valerianaceae), Lauren A. Gonzalez

LSU New Orleans Theses and Dissertations

Species of Valerianaceae in South America represent one of the best examples of rapid diversification on a continental scale. The phylogeny of Valerianaceae has received a lot of attention within the last 10 years, but relationships among the South American species are fairly unresolved. Results from previous studies have not been well resolved with traditional genetic markers, most likely due to its recent and rapid radiation. Species in this clade exhibit a variety mating systems and inflorescence types. For the first part of this research I used several traditional plastid markers, and 3 new low copy nuclear markers to better …

Comparative Population Assessments Of Nautilus Sp. In The Philippines, Australia, Fiji, And American Samoa Using Baited Remote Underwater Video Systems, Gregory Jeff Barord, Frederick Dooley, Andrew Dunstan, Anthony Ilano, Karen N. Keister, Heike Neumeister, Thomas Preuss, Shane Schoepfer, Peter D. Ward

Publications and Research

The extant species of Nautilus and Allonautilus (Cephalopoda) inhabit fore-reef slope environments across a large geographic area of the tropical western Pacific and eastern Indian Oceans. While many aspects of their biology and behavior are now well-documented, uncertainties concerning their current populations and ecological role in the deeper, fore-reef slope environments remain. Given the historical to current day presence of nautilus fisheries at various locales across the Pacific and Indian Oceans, a comparative assessment of the current state of nautilus populations is critical to determine whether conservation measures are warranted. We used baited remote underwater video systems (BRUVS) to make …

Early Back-To-Africa Migration Into The Horn Of Africa, Jason A. Hodgson, Connie J. Mulligan, Ali Al-Meeri, Ryan L. Raaum

Publications and Research

Genetic studies have identified substantial non-African admixture in the Horn of Africa (HOA). In the most recent genomic studies, this non-African ancestry has been attributed to admixture with Middle Eastern populations during the last few thousand years. However, mitochondrial and Y chromosome data are suggestive of earlier episodes of admixture. To investigate this further, we generated new genome-wide SNP data for a Yemeni population sample and merged these new data with published genome-wide genetic data from the HOA and a broad selection of surrounding populations. We used multidimensional scaling and ADMIXTURE methods in an exploratory data analysis to develop hypotheses …

The Effect Of Population History On Hominoid Intraspecific Cranial Shape Diversity: Combining Population Genetic And 3d Geometric Morphometric Data, Julia Marie Zichello

Dissertations, Theses, and Capstone Projects

Cranial shape diversity within hominoids has been previously studied with the aim of understanding how levels of diversity in extant species compare with extinct hominin specimens. This dissertation addresses the question of why cranial shape diversity differs among extant hominoids. Levels of intraspecific cranial shape diversity are highly varied among hominoids. For example, Sumatran orangutan cranial shape diversity is more than twice that of all living humans. Here, the population history of each species, or sub-species, is considered as a force potentially structuring phenotypic variation. It is already well established that population history has shaped patterns of modern human cranial …

The Evolution Of Respiratory O2/No Reductases: An Out-Of-The-Phylogenetic-Box Perspective, Anne-Lise Ducluzeau, Barbara Schoepp-Cothenet, Robert Van Lis, Frauke Baymann, Michael J. Russell, Wilfgang Nitschke

Department of Biochemistry: Faculty Publications

Complex life on our planet crucially depends on strong redox disequilibria afforded by the almost ubiquitous presence of highly oxidizing molecular oxygen. However, the history of O₂-levels in the atmosphere is complex and prior to the Great Oxidation Event some 2.3 billion years ago, the amount of O₂ in the biosphere is considered to have been extremely low as compared with present-day values. Therefore the evolutionary histories of life and of O₂-levels are likely intricately intertwined. The obvious biological proxy for inferring the impact of changing O₂-levels on life is the evolutionary history …

Early Song Discrimination By Nestling Sparrows In The Wild, Daizaburo Shizuka

School of Biological Sciences: Faculty Publications

Songs play an important role in premating isolation in birds. However, when songs are learned, expe- rience with both conspecific and heterospecific songs in early life could lead to the development of both mixed songs and mixed preferences. One way that such learning errors can be prevented is if birds can discriminate between songs of different species prior to learning and preferentially memorize conspe- cific songs. Prior captive studies have shown that white-crowned sparrows, Zonotrichia leucophrys, are able to discriminate songs early in the process of song memorization, after about 10 days since hatching. I studied early song discrimination in …

Photosynthetic Thermal Tolerance And Recovery To Short Duration Temperature Stress In Desert And Montane Plants: A Comparative Study, David William Gallagher

Master's Theses

• Climate change models predict an increase in frequency and amplitude of extreme weather events, including heat waves. To better predict how the composition and distribution of plant assemblages might respond to these changes in temperature, it is important to understand how species currently respond to these extremes. Photosynthetic thermal tolerance (T₂₅)and photosynthetic recovery (RT₂₅) were quantified in 27 species. We also studied the relationships between T₂₅, RT₂₅ and leaf mass per area (LMA). Leaf temperature was also monitored in the field.
• Leaves used in this study were collected from two distinct …

Joint Phenotypes, Evolutionary Conflict And The Fundamental Theorem Of Natural Selection, David C. Queller

Biology Faculty Research

Multiple organisms can sometimes affect a common phenotype. For example, the portion of a leaf eaten by an insect is a joint phenotype of the plant and insect and the amount of food obtained by an offspring can be a joint trait with its mother. Here, I describe the evolution of joint phenotypes in quantitative genetic terms. A joint phenotype for multiple species evolves as the sum of additive genetic variances in each species, weighted by the selection on each species. Selective conflict between the interactants occurs when selection takes opposite signs on the joint phenotype. The mean fitness of …

A Male Spider’S Ornamentation Polymorphism Maintained By Opposing Selection With Two Niches, Bo Deng, Alex Estes, Brett Grieb, Douglas Richard, Brittney Hinds, Eileen Hebets

Eileen Hebets Publications

The Levene mechanism to maintain genotypic polymorphism by opposing selection on genotypes in multiple niches was proposed 60 years ago, and yet no systems were found to satisfy the mechanisms rather restrictive conditions. Reported here is such an example that a wolf spider population lives in a habitat of mixed rocks and leafy litter for which the females are phenotypically indistinguishable and the males have two distinct phenotypes subject to opposing selection with respect to the substrates. Census data is best-fitted to a population genetics model of the Levene type. A majority of the best fit support polymorphism, with many …