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Articles 1021 - 1050 of 1390

Full-Text Articles in Ecology and Evolutionary Biology

Evaluating Species Responses To Climate Change Using Ecological Niche Modeling And Genetic Data, Jeanette Perry Aug 2011

Evaluating Species Responses To Climate Change Using Ecological Niche Modeling And Genetic Data, Jeanette Perry

Undergraduate Research Opportunities Program (UROP)

The current and projected future warming trends together with degradation of habitats throughout much of the Great Basin and Columbian Plateau represent real threats to many species occupying these regions. If we can determine the impacts of past climatic changes on the distribution of species, we can obtain a better understanding of the future impacts of projected climatic trends on many species in these regions. My results with the Great Basin Pocket Mouse (Perognathus parvus) may be relevant to conservation ecologists and resource managers attempting to protect several Endangered Species Act candidates, such as the pygmy cottontail (Brachylagus idahoensis). I …


Systematics Of African Skink In The Panaspis Wahlbergi Complex, Ma. Fernanda Medina^, Eli Greenbaum* Jul 2011

Systematics Of African Skink In The Panaspis Wahlbergi Complex, Ma. Fernanda Medina^, Eli Greenbaum*

COURI Symposium Abstracts, Summer 2011

No abstract provided.


Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo Jul 2011

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …


Phylogeography Of The Reef Fish Cephalopholis Argus(Epinephelidae) Indicates Pleistocene Isolation Across The Indo-Pacific Barrier With Contemporary Overlap In The Coral Triangle, Michelle R. Gaither, Brian W. Bowen, Tiana-Rae Bordenave, Luiz A. Rocha, Stephen J. Newman, Juan A. Gomez, Lynne Van Herwerden, Matthew T. Craig Jul 2011

Phylogeography Of The Reef Fish Cephalopholis Argus(Epinephelidae) Indicates Pleistocene Isolation Across The Indo-Pacific Barrier With Contemporary Overlap In The Coral Triangle, Michelle R. Gaither, Brian W. Bowen, Tiana-Rae Bordenave, Luiz A. Rocha, Stephen J. Newman, Juan A. Gomez, Lynne Van Herwerden, Matthew T. Craig

Fisheries Research Articles

Background

The Coral Triangle (CT), bounded by the Philippines, the Malay Peninsula, and New Guinea, is the epicenter of marine biodiversity. Hypotheses that explain the source of this rich biodiversity include 1) the center of origin, 2) the center of accumulation, and 3) the region of overlap. Here we contribute to the debate with a phylogeographic survey of a widely distributed reef fish, the Peacock Grouper (Cephalopholis argus; Epinephelidae) at 21 locations (N = 550) using DNA sequence data from mtDNA cytochrome b and two nuclear introns (gonadotropin-releasing hormone and S7 ribosomal protein).

Results

Population structure was significant …


Evolutionary Patterns In Deep-Sea Mollusks, Elizabeth Ellen Boyle Jun 2011

Evolutionary Patterns In Deep-Sea Mollusks, Elizabeth Ellen Boyle

Graduate Doctoral Dissertations

The evolution of deep-sea fauna is poorly known. We know little about the scales of population differentiation, radiation and colonization of the deep sea. This dissertation explores evolution in the deep sea at the level of population differentiation on ocean-wide scales in a gastropod species Benthonella tenella and phylogeny of a deep-sea subfamily of protobranch bivalves, Ledellinae. While working on the phylogeny of the Ledellinae the presence of mitochondrial heteroplasmy was discovered.

Genetic variation was quantified within and among populations of deep-sea gastropod Benthonella tenella to identify the extent of population differentiation and potential mechanisms that might isolate gene pools. …


The Role Of Historical And Contemporary Processes On Phylogeographic Structure And Genetic Diversity In The Northern Cardinal, Cardinalis Cardinalis, Brian T. Smith, Patricia Escalante, Blanca E. Hernandez-Banos, Adolfo G. Navarro-Siguenza, Sievert Rohwer, John Klicka May 2011

The Role Of Historical And Contemporary Processes On Phylogeographic Structure And Genetic Diversity In The Northern Cardinal, Cardinalis Cardinalis, Brian T. Smith, Patricia Escalante, Blanca E. Hernandez-Banos, Adolfo G. Navarro-Siguenza, Sievert Rohwer, John Klicka

Ornithology Program (HRC)

Background

Earth history events such as climate change are believed to have played a major role in shaping patterns of genetic structure and diversity in species. However, there is a lag between the time of historical events and the collection of present-day samples that are used to infer contemporary population structure. During this lag phase contemporary processes such as dispersal or non-random mating can erase or reinforce population differences generated by historical events. In this study we evaluate the role of both historical and contemporary processes on the phylogeography of a widespread North American songbird, the Northern Cardinal, Cardinalis cardinalis …


Molecular Evolution And Historical Biogeography Of New World Birds, Brian T. Smith May 2011

Molecular Evolution And Historical Biogeography Of New World Birds, Brian T. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Deciphering the patterns of how biodiversity has evolved across time and space has remained a fundamental objective for biologists for the last 200 years. Researchers are faced with the challenge of interpreting the complexity of evolutionary patterns that have been generated over the deep history of the Earth. The advancement of DNA sequencing technology has yielded a new and powerful genetic toolkit that has allowed biologists to address novel evolutionary questions. For my dissertation research, I used molecular genetics and a statistical framework to study the evolution and historical biogeography of birds distributed in North and South America. My dissertation …


Oral Presentation: Plant Genes And Drought Tolerance, Norris Lam Apr 2011

Oral Presentation: Plant Genes And Drought Tolerance, Norris Lam

Festival of Communities: UG Symposium (Posters)

Research has shown that a gene from C3 xerophyte Larrea tridentata (creosote bush), LtWRKY21, is involved in pathways governing creosote bush’s high tolerance to environmental stress. By understanding the way in which creosote bush adapts to drought, crop plants can be engineered to be more drought tolerant during times of imminent global climate change. To study the underlying mechanisms of creosote bush drought response, the LtWRKY21 gene was mobilized into the model organism Arabidopsis thaliana. Chlorophyll degradation, cellular electrolyte leakage, and water content in leaves will serve as indicators of drought tolerance in LtWRKY21-transgenic A. thaliana after treatment in chemically …


Stationary Phase Mutagenesis In Bacillus Subtilisis Independent Of Genome Replication, Mark Upchurch, Holly Martin, Eduardo Robleto Apr 2011

Stationary Phase Mutagenesis In Bacillus Subtilisis Independent Of Genome Replication, Mark Upchurch, Holly Martin, Eduardo Robleto

Festival of Communities: UG Symposium (Posters)

Stationary phase mutagenesis is defined as cellular mechanisms that produce genetic diversity in cells experiencing conditions of stress. These processes are associated with many biological phenomena, including those that produce the formation of cancers in animal cells and other degenerative diseases. Also, these mechanisms are associated with the accumulation of beneficial mutations in bacteria, but follow stochastic processes and are controlled by genetic factors. The current models explaining the generation of stress-induced mutations are predicated on the formation of DNA replication intermediates that are formed during the repair of damaged DNA or during DNA replication and transcription encounters. Here we …


Draft Genome Of The Red Harvester Ant Pogonomyrmex Barbatus, Chris R. Smith, Christopher D. Smith, Hugh M. Robertson, Martin Helmkampf, Aleksey Zimin, Mark Yandall, Carson Holt, Hao Hu, Ehab Abouheif, Richard Benton, Elizabeth Cash, Vincent Croset, Cameron R. Currie, Eran Elhaik, Christine G. Elsik, Marie-Julie Favé, Vilaiwan Fernandes, Joshua D. Gibson, Dan Graur, Wulfila Gronenberg, Kirk J. Grubbs, Darren E. Hagen, Ana Sofia Ibarraran Viniegra, Brian R. Johnson, Reed M. Johnson, Abderrahman Khila, Jay W. Kim, Kaitlyn A, Mathis, Monica C. Munoz-Torres, Marguerite C. Murphy, Julie A. Mustard, Rin Nakamura, Oliver Niehuis, Surabhi Nigam, Rick P. Overson, Jennifer E. Placek, Rajendhran Rajakumar, Justin T. Reese, Garret Suen, Shu Tao, Candice W. Torres, Neil D. Tsutsui, Lumi Viljakainen, Florian Wolschin, Jürgen Gadau Apr 2011

Draft Genome Of The Red Harvester Ant Pogonomyrmex Barbatus, Chris R. Smith, Christopher D. Smith, Hugh M. Robertson, Martin Helmkampf, Aleksey Zimin, Mark Yandall, Carson Holt, Hao Hu, Ehab Abouheif, Richard Benton, Elizabeth Cash, Vincent Croset, Cameron R. Currie, Eran Elhaik, Christine G. Elsik, Marie-Julie Favé, Vilaiwan Fernandes, Joshua D. Gibson, Dan Graur, Wulfila Gronenberg, Kirk J. Grubbs, Darren E. Hagen, Ana Sofia Ibarraran Viniegra, Brian R. Johnson, Reed M. Johnson, Abderrahman Khila, Jay W. Kim, Kaitlyn A, Mathis, Monica C. Munoz-Torres, Marguerite C. Murphy, Julie A. Mustard, Rin Nakamura, Oliver Niehuis, Surabhi Nigam, Rick P. Overson, Jennifer E. Placek, Rajendhran Rajakumar, Justin T. Reese, Garret Suen, Shu Tao, Candice W. Torres, Neil D. Tsutsui, Lumi Viljakainen, Florian Wolschin, Jürgen Gadau

Department of Entomology: Faculty Publications

We report the draft genome sequence of the red harvester ant, Pogonomyrmex barbatus. The genome was sequenced using 454 pyrosequencing, and the current assembly and annotation were completed in less than 1 y. Analyses of conserved gene groups (more than 1,200 manually annotated genes to date) suggest a high-quality assembly and annotation comparable to recently sequenced insect genomes using Sanger sequencing. The red harvester ant is a model for studying reproductive division of labor, phenotypic plasticity, and sociogenomics. Although the genome of P. barbatus is similar to other sequenced hymenopterans (Apis mellifera and Nasonia vitripennis) in …


Drafting Human Ancestry: What Does The Neanderthal Genome Tell Us About Hominid Evolution? Commentary On Green Et Al. (2010), Michael Hofreiter Mar 2011

Drafting Human Ancestry: What Does The Neanderthal Genome Tell Us About Hominid Evolution? Commentary On Green Et Al. (2010), Michael Hofreiter

Human Biology

Ten years after the first draft versions of the human genome were
announced, technical progress in both DNA sequencing and ancient DNA
analyses has allowed a research team around Ed Green and Svante Pa¨a¨bo to
complete this task from infinitely more difficult hominid samples: a few
pieces of bone originating from our closest, albeit extinct, relatives, the
Neanderthals. Pulling the Neanderthal sequences out of a sea of contaminating
environmental DNA impregnating the bones and at the same time
avoiding the problems of contamination with modern human DNA is in itself
a remarkable accomplishment. However, the crucial question in the long …


Leaf Number Indicates Salt Tolerance Of Young Seedling Families Of European Aspen (Populus Tremula L.) Growing In Different Soils, Lu-Min Vaario, Kim Yrjälä, Matti Rousi, Timo Sipila, Pertti Pulkkinen Mar 2011

Leaf Number Indicates Salt Tolerance Of Young Seedling Families Of European Aspen (Populus Tremula L.) Growing In Different Soils, Lu-Min Vaario, Kim Yrjälä, Matti Rousi, Timo Sipila, Pertti Pulkkinen

Aspen Bibliography

Soil salinity limits plant productivity and quality. We evaluated the response of 12 aspen (Populus tremula) families to salt stress in two different soils irrigated for 4-weeks with 0, 80 or 160 mM saline solution. Easily measurable characteristics such as shoot height, leaf number, dry mass as well as the distribution of sodium (Na+) ions were measured in 5-month-old aspen seedlings raised in controlled greenhouse conditions on two different soils. Growth among families varied significantly, and the interaction between family and soil type was significant. From 2–5 months, leaf number correlated with that of the first month and salin-ity tolerance. …


Reduced Mhc And Neutral Variation In The Galápagos Hawk, An Island Endemic, Jennifer Bollmer, Joshua Hull, Holly Ernest, José Sarasola, Patricia Parker Jan 2011

Reduced Mhc And Neutral Variation In The Galápagos Hawk, An Island Endemic, Jennifer Bollmer, Joshua Hull, Holly Ernest, José Sarasola, Patricia Parker

Biology Department Faculty Works

BackgroundGenes at the major histocompatibility complex (MHC) are known for high levels of polymorphism maintained by balancing selection. In small or bottlenecked populations, however, genetic drift may be strong enough to overwhelm the effect of balancing selection, resulting in reduced MHC variability. In this study we investigated MHC evolution in two recently diverged bird species: the endemic Galápagos hawk (Buteo galapagoensis), which occurs in small, isolated island populations, and its widespread mainland relative, the Swainson's hawk (B. swainsoni).ResultsWe amplified at least two MHC class II B gene copies in each species. We recovered only three different sequences from 32 Galápagos …


Multicentury Fire And Forest Histories At 19 Sites In Utah And Eastern Nevada, Emily K. Heyerdahl, Peter M. Brown, Stanley G. Kitchen, Marc H. Weber Jan 2011

Multicentury Fire And Forest Histories At 19 Sites In Utah And Eastern Nevada, Emily K. Heyerdahl, Peter M. Brown, Stanley G. Kitchen, Marc H. Weber

Aspen Bibliography

Our objective is to provide site-specific fire and forest histories from Utah and eastern Nevada that can be used for land management or additional research. We systematically sampled fire scars and tree-recruitment dates across broad gradients in elevation and forest type at 13 sites in Utah and 1 in eastern Nevada to characterize spatial and temporal variation in historical fire regimes as well as forest structure and composition. We collected similar data non-systematically at five additional sites in Utah. These 19 sites include a broad range of forest types (from pinyon-juniper woodlands to spruce-fir forests) and fire regime types. In …


Variation, Systematics, And Relationships Of The Leptodactylus Bolivianus Complex (Amphibia: Anura: Leptodactylidae), W. Ronald Heyer, Rafael O. De Sá Jan 2011

Variation, Systematics, And Relationships Of The Leptodactylus Bolivianus Complex (Amphibia: Anura: Leptodactylidae), W. Ronald Heyer, Rafael O. De Sá

Biology Faculty Publications

Heyer, W. Ronald, and Rafael O. de Sá. Variation, Systematics, and Relationships of the Leptodactylus bolivianus Complex (Amphibia: Anura: Leptodactylidae). Smithsonian Contributions to Zoology, number 635, viii + 58 pages, 21 figures, 20 tables, 2011.—The Leptodactylus bolivianuscomplex has been considered to consist of one or two species, L. bolivianus alone or L. bolivianus and L. insularum. Detailed morphological analyses were undertaken to evaluate variation in the complex, which ranges from Costa Rica through Panama, across northern South America in the river valleys draining to the Caribbean, and throughout much of the Amazon basin with southern limits in Bolivia. Members of …


Population And Conservation Genetics Of Crawfish Frogs, Lithobates Areolatus, At Their Northeastern Range Limits, Schyler O. Nunziata Jan 2011

Population And Conservation Genetics Of Crawfish Frogs, Lithobates Areolatus, At Their Northeastern Range Limits, Schyler O. Nunziata

Online Theses and Dissertations

Crawfish Frogs (Lithobates areolatus) are state endangered in Indiana and Iowa, with populations in decline throughout their range. I studied populations of Crawfish Frogs on local and statewide scales at their northeastern range limits to (1) assess the level of genetic diversity within populations (2) estimate fine-scale genetic structure, and (3) estimate genetic differentiation between populations at the state level. Crawfish Frogs breed in temporary pools and wetlands, and have high breeding-pond fidelity; therefore I predicted to find genetic differences between ponds at small geographic scales. I used 10 microsatellite loci to genotype frogs collected from three primary populations in …


Oregon Aspen Project, Forest Restoration Partnership Dec 2010

Oregon Aspen Project, Forest Restoration Partnership

Aspen Bibliography

The Oregon Aspen Project was initiated in response to the decline of aspen groves in Oregon and throughout the Western United States, and the lack of information to guide managers interested in stewardship to enhance this resource. There were three central goals and accompanying objectives for this project which are listed below. The project accomplishments are provided below each bulleted objective


Reconstructing Species Responses To Past Climatic Changes Using Niche Modeling And Genetic Data, Tereza Jezkova Dec 2010

Reconstructing Species Responses To Past Climatic Changes Using Niche Modeling And Genetic Data, Tereza Jezkova

UNLV Theses, Dissertations, Professional Papers, and Capstones

Glacial – interglacial cycles have a pronounced impact on species distributions and genetic structure. Many species shift their distributions to lower latitudes and altitudes during the colder glacial periods and expand northwards and up the elevation during warmer interglacial periods. Some species however are capable of adapting to changing environment which allows them to persist in place despite climatic changes. I explored how climatic changes after the last glacial maximum (LGM) effected two species inhabiting the deserts of western North America: one mammal (Chisel-toothed Kangaroo Rat, Dipodomys microps) and one reptile (Desert Horned Lizard, Phrynosoma platyrhinos). I used …


Phenotypic And Genetic Characterization Of Wildland Collections Of Western And Searls Prairie Clovers For Rangeland Revegetation In The Western Usa, Kishor Bhattarai Dec 2010

Phenotypic And Genetic Characterization Of Wildland Collections Of Western And Searls Prairie Clovers For Rangeland Revegetation In The Western Usa, Kishor Bhattarai

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and ecotypic variation of these prairie clovers is a prerequisite for developing populations suitable for rangeland revegetation in the western USA. DNA sequences of internal transcribed spacer (ITS/5.8S) and trnK/matK were used to study the phylogeny of these species. The species were distinguished …


Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson Nov 2010

Micrornas Reveal The Interrelationships Of Hagfish, Lampreys, And Gnathostomes And The Nature Of The Ancestral Vertebrate, Alysha M. Heimberg, Richard Cowper-Sal{Middle Dot}Lari, Marie Semon, Philip C. J. Donoghue, Kevin J. Peterson

Dartmouth Scholarship

Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate. However, this insight has been obscured by controversy over their interrelationships. Morphological cladistic analyses have identified lampreys and gnathostomes as closest relatives, whereas molecular phylogenetic studies recover a monophyletic Cyclostomata (hagfish and lampreys as closest relatives). Here, we show through deep sequencing of small RNA libraries, coupled with genomic surveys, that Cyclostomata is monophyletic: hagfish and lampreys share 4 unique microRNA families, 15 unique paralogues of more …


Evolutionary Rates And Gene Dispensability Associate With Replication Timing In The Archaeon Sulfolobus Islandicus, Kenneth M. Flynn, Samuel H. Vohr, Philip J. Hatcher, Vaughn S. Cooper Oct 2010

Evolutionary Rates And Gene Dispensability Associate With Replication Timing In The Archaeon Sulfolobus Islandicus, Kenneth M. Flynn, Samuel H. Vohr, Philip J. Hatcher, Vaughn S. Cooper

Molecular, Cellular & Biomedical Sciences

In bacterial chromosomes, the position of a gene relative to the single origin of replication generally reflects its replication timing, how often it is expressed, and consequently, its rate of evolution. However, because some archaeal genomes contain multiple origins of replication, bias in gene dosage caused by delayed replication should be minimized and hence the substitution rate of genes should associate less with chromosome position. To test this hypothesis, six archaeal genomes from the genus Sulfolobus containing three origins of replication were selected, conserved orthologs were identified, and the evolutionary rates (dN and dS) of these orthologs were quantified. Ortholog …


Plastic And Genetic Determination Of Population, Community, And Ecosystem Properties In Freshwater Environments, Leigh C. Latta Iv May 2010

Plastic And Genetic Determination Of Population, Community, And Ecosystem Properties In Freshwater Environments, Leigh C. Latta Iv

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The hierarchy of biological organization, from molecules to ecosystems, describes the relationships among various biological systems. Of particular interest is assessing how the factors that primarily determine the nature of one hierarchical level also have transcendent qualities that affect the ecology and evolution of higher hierarchical levels. The goal of this dissertation was to use a bottom-up approach to examine the transcendent effects of two factors that strongly determine the nature of their associated level of biological organization. The first, phenotypic plasticity, is a primary factor that determines the phenotype of an individual. The second factor, genetic diversity, largely determines …


Genomic Perspectives On Evolution In Bracken Fern, Joshua P. Der May 2010

Genomic Perspectives On Evolution In Bracken Fern, Joshua P. Der

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The fern genus Pteridium comprises a number of closely related species distributed throughout the world. Collectively they are called bracken ferns and have historically been treated as a single species, Pteridium aquilinum. Bracken is notorious as a toxic weed that colonizes open fields and poisons livestock. Bracken is also easily cultured and has become one of the most intensively studied ferns. Bracken has been used as a model system for the study of the fern life cycle, fern gametophyte development, the pheromonal mechanism of sex determination, toxicology, invasion ecology, and climate change. This dissertation places bracken within a global …


An Entrepreneurial Approach To Librarianship, Flora Shrode, Jennifer Duncan, Wendy Holliday Apr 2010

An Entrepreneurial Approach To Librarianship, Flora Shrode, Jennifer Duncan, Wendy Holliday

Library Faculty & Staff Publications

Librarians from Utah State University explain recent efforts to encourage subject librarians to take a more holistic view of their roles. We are shifting from a traditional emphasis primarily on collection development and refocusing on natural connections between collections, instruction, liaison, and reference service. The poster provides background about Utah State University’s situation and explains our approach to analyzing local needs and culture to inform development of a new organizational structure. We describe our vision of subject librarianship, the process by which we assessed librarians’ ideas and goals for performing as subject librarians, and the actions we are taking to …


Damage Agents And Condition Of Mature Aspen Stands In Montana And Northern Idaho, Brytten E. Steed, Holly S.J. Kearns Apr 2010

Damage Agents And Condition Of Mature Aspen Stands In Montana And Northern Idaho, Brytten E. Steed, Holly S.J. Kearns

Aspen Bibliography

No abstract provided.


Genetic Variation At Nuclear Loci Fails To Distinguish Two Morphologically Distinct Species Of Aquilegia, Elizabeth A. Cooper, Justen B. Whittall, Scott A. Hodges, Magnus Nordborg Jan 2010

Genetic Variation At Nuclear Loci Fails To Distinguish Two Morphologically Distinct Species Of Aquilegia, Elizabeth A. Cooper, Justen B. Whittall, Scott A. Hodges, Magnus Nordborg

Biology

Aquilegia formosa and pubescens are two closely related species belonging to the columbine genus. Despite their morphological and ecological differences, previous studies have revealed a large degree of intercompatibility, as well as little sequence divergence between these two taxa [1,2]. We compared the inter- and intraspecific patterns of variation for 9 nuclear loci, and found that the two species were practically indistinguishable at the level of DNA sequence polymorphism, indicating either very recent speciation or continued gene flow. As a comparison, we also analyzed variation at two loci across 30 other Aquilegia taxa; this revealed slightly more differentiation among taxa, …


Sex, Mixability, And Modularity, Adi Livnat, Christos Papadimitriou, Nicholas Pippenger, Marcus W. Feldman Jan 2010

Sex, Mixability, And Modularity, Adi Livnat, Christos Papadimitriou, Nicholas Pippenger, Marcus W. Feldman

All HMC Faculty Publications and Research

The assumption that different genetic elements can make separate contributions to the same quantitative trait was originally made in order to reconcile biometry and Mendelism and ever since has been used in population genetics, specifically for the trait of fitness. Here we show that sex is responsible for the existence of separate genetic effects on fitness and, more generally, for the existence of a hierarchy of genetic evolutionary modules. Using the tools developed in the process, we also demonstrate that in terms of their fitness effects, separation and fusion of genes are associated with the increase and decrease of the …


Phylogeographical Patterns Of Neobalanocarpus Heimii (Dipterocarpaceae) For The Evolutionary History And Chain Of Custody Certification., Tnah Lee Hong Jan 2010

Phylogeographical Patterns Of Neobalanocarpus Heimii (Dipterocarpaceae) For The Evolutionary History And Chain Of Custody Certification., Tnah Lee Hong

Student Works (2010-2019)

Tectonic movement and climatic oscillations during the Cenozoic have had dramatic effect on the biota of the tropical rain forest. This study aims to reveal the phylogeography and evolutionary history of a Peninsular Malaysian endemic tropical timber, Neobalanocarpus heimii (Dipterocarpaceae), based on chloroplast DNA (cpDNA) variation. Fifteen haplotypes were identified from 10 intraspecific variable sites of five non-coding cpDNA regions: trnL intron, trnS-trnG spacer, trnG intron, trnK intron and psbK-trnS spacer. Two major genealogical cpDNA lineages of N. heimii were elucidated: a widespread southern and a northern region. The species is predicted to survive in multiple refugia during climatic oscillation: …


Ecology And Genetics Of Philodina Megalotrocha (Rotifera, Bdelloidea) From Chihuahuan Desert Populations, Lina Kamel Hamdan Jan 2010

Ecology And Genetics Of Philodina Megalotrocha (Rotifera, Bdelloidea) From Chihuahuan Desert Populations, Lina Kamel Hamdan

Open Access Theses & Dissertations

The Chihuahuan Desert is a unique region with high biodiversity. There is a high degree endemism of freshwater biota, but relatively few studies have been focused on zooplankton. Bdelloid rotifers are one component of these ecosystems and often dominate very temporary habitats. Bdelloids are usually assumed to be cosmopolitan species due to their potentially high dispersal rates. Distribution records of the bdelloid P. megalotrocha extend from North America to New Zealand. However, little is known about its ecology or genetics. The aims of this study are to: 1) determine whether the distribution of P. megalotrocha in the Chihuahuan Desert is …


Systematics Of The Genus Ptychadena Boulenger, 1917 (Anura: Ptychadenidae) From Democratic Republic Of The Congo, Katrina Marie Weber Jan 2010

Systematics Of The Genus Ptychadena Boulenger, 1917 (Anura: Ptychadenidae) From Democratic Republic Of The Congo, Katrina Marie Weber

Open Access Theses & Dissertations

This thesis increases the scope of previous phylogenetic analyses that revealed high levels of genetic differentiation within the anuran genus Ptychadena. Herein, I increase sampling of Central African populations of Ptychadena by over six times to examine their relationships to other African populations and to search for cryptic species. This study represents the most comprehensive molecular phylogeny of Ptychadena to date. A total of three mitochondrial (12S, 16S, and cyt b) and two nuclear (RAG1 and rhodopsin) genes were sequenced for 67 specimens of Ptychadena. Maximum parsimony, maximum likelihood, and Bayesian analyses were conducted. These analyses revealed …