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Ecology and Evolutionary Biology

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Articles 961 - 990 of 1385

Full-Text Articles in Genetics and Genomics

Long-Term Data For Endemic Frog Genera Reveal Potential Conservation Crisis In The Bale Mountains, Ethiopia, David J. Gower, Roman K. Aberra, Silvia Schwaller, Malcolm J. Largen, Ben Collen, Stephen Spawls, Michele Menegon, Breda M. Zimkus, Rafael O. De Sá, Et Al. Jan 2013

Long-Term Data For Endemic Frog Genera Reveal Potential Conservation Crisis In The Bale Mountains, Ethiopia, David J. Gower, Roman K. Aberra, Silvia Schwaller, Malcolm J. Largen, Ben Collen, Stephen Spawls, Michele Menegon, Breda M. Zimkus, Rafael O. De Sá, Et Al.

Biology Faculty Publications

Populations of many frogs have declined alarmingly in recent years, placing nearly one third of the > 6,000 species under threat of extinction. Declines have been attributed largely to habitat loss, environmental degradation and/or infectious diseases such as chytridiomycosis. Many frogs undergo dramatic natural population fluctuations such that long-term data are required to determine population trends without undue influence of stochastic factors. We present long-term quantitative data (individuals encountered per person hour of searching) for four monotypic frog genera endemic to an Afromontane region of exceptional importance but growing conservation concern: one endemic to the Ethiopian highlands (Spinophrynoides osgoodi) and three …


Reconstruction Of Family-Level Phylogenetic Relationships Within Demospongiae (Porifera) Using Nuclear Encoded Housekeeping Genes, Malcolm Hill, April L. Hill, Et. Al. Jan 2013

Reconstruction Of Family-Level Phylogenetic Relationships Within Demospongiae (Porifera) Using Nuclear Encoded Housekeeping Genes, Malcolm Hill, April L. Hill, Et. Al.

Biology Faculty Publications

Background: Demosponges are challenging for phylogenetic systematics because of their plastic and relatively simple morphologies and many deep divergences between major clades. To improve understanding of the phylogenetic relationships within Demospongiae, we sequenced and analyzed seven nuclear housekeeping genes involved in a variety of cellular functions from a diverse group of sponges.

Methodology/Principal Findings: We generated data from each of the four sponge classes (i.e., Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha), but focused on family-level relationships within demosponges. With data for 21 newly sampled families, our Maximum Likelihood and Bayesian-based approaches recovered previously phylogenetically defined taxa: Keratosap, Myxospongiae …


Phylogeography Of The Christmas Tree Worm Spirobranchus Corniculatus (Annelida, Serpulidae) From The Coral Triangle, Australia, And Fiji, Abril Iñiguez, Craig J. Starger, Elena Kupriyanova, Demian Willette, Tristan Varman, Joshua A. Drew, Abdul Hamid Toha, Benedict Maralit, Kent E. Carpenter, Paul H. Barber Jan 2013

Phylogeography Of The Christmas Tree Worm Spirobranchus Corniculatus (Annelida, Serpulidae) From The Coral Triangle, Australia, And Fiji, Abril Iñiguez, Craig J. Starger, Elena Kupriyanova, Demian Willette, Tristan Varman, Joshua A. Drew, Abdul Hamid Toha, Benedict Maralit, Kent E. Carpenter, Paul H. Barber

Biological Sciences Faculty Publications

Christmas Tree Woms is a common name given to a group of large and colourful serpulid polychaetes of the genus Spirobranchus that are obligate symbionts of hermatypic corals commonly found in tropical and subtropical regions world-wide. While current taxonomic species delimitations of these worms are based almost exclusively on the morphology of opercular structures, particularly the number and shape of calcareous opercular horns, high levels of intraspecific variation in this morphological feature have made species boundaries within the genus difficult to resolve. Molecular work to differentiate serpulid worms has long been hampered by the availability of informative markers. Recent work …


No Evidence For A Relationship Between Hemolymph Ecdysteroid Levels And Female Reproductive Behavior In Schizocosa Wolf Spiders, Reed M. Stubbendieck, Anthony J. Zera, Eileen A. Hebets Jan 2013

No Evidence For A Relationship Between Hemolymph Ecdysteroid Levels And Female Reproductive Behavior In Schizocosa Wolf Spiders, Reed M. Stubbendieck, Anthony J. Zera, Eileen A. Hebets

Eileen Hebets Publications

This study used radioimmunoassay (RIA) to explore the relationship between levels of hemolymph ecdysteroids and female reproductive behavior in Schizocosa wolf spiders. Specifically, we investigated the relationship between circulating ecdysteroid concentrations in females and 1) likelihood to copulate, or female receptivity [Experiment I— Schizocosa avida (Walckenaer 1837)], 2) time post copulation (Experiment 2— Schizocosa rovneri Uetz & Dondale 1979) and 3) exposure to conspecific male courtship (Experiment 3— Schizocosa uetzi Stratton 1997). In Experiment 1, we expected higher levels of circulating ecdysteroids in receptive versus unreceptive females, based upon prior research demonstrating an increase in receptivity following injections of 20-hydroexyedysone …


Transcriptome Characterization And Detection Of Gene Expression Differences In Aspen (Populus Tremuloides), Hardeep S. Rai, Karen E. Mock, Bryce A. Richardson, Richard C. Cronn, Katherine J. Hayden, Jessica W. Wright, Brian J. Knaus, Paul G. Wolf Jan 2013

Transcriptome Characterization And Detection Of Gene Expression Differences In Aspen (Populus Tremuloides), Hardeep S. Rai, Karen E. Mock, Bryce A. Richardson, Richard C. Cronn, Katherine J. Hayden, Jessica W. Wright, Brian J. Knaus, Paul G. Wolf

Aspen Bibliography

No abstract provided.


Wolf Creek Ranch Aspen Monitoring Report, Paul C. Rogers, Allison Jones, James Catlin, James Shuler, Arthur Morris, Michael Kuhns Jan 2013

Wolf Creek Ranch Aspen Monitoring Report, Paul C. Rogers, Allison Jones, James Catlin, James Shuler, Arthur Morris, Michael Kuhns

Aspen Bibliography

In the summer of 2012 we undertook a landscape assessment of aspen forest conditions at Wolf Creek Ranch (WCR) near Kamas, Utah. Using a geographic information system (GIS) coverage of predicted aspen coverage, fifty systematically selected field "plots" were located and mapped with aspen stands around WCR. Seven plots were eventually discarded from our survey due to lack of aspen cover. Volunteer field crews, mostly WCR homeowners, collected aspen data documenting tree sizes, height/age groups, diameters, reproduction, mortality, browse levels, and browse animal use levels.


A Path To Success? A Review Of Evolution, Development, And The Predictable Genome By David L. Stern, Hope Hollocher, Charles H. Pence, Grant Ramsey, Michelle M. Wirth Jan 2013

A Path To Success? A Review Of Evolution, Development, And The Predictable Genome By David L. Stern, Hope Hollocher, Charles H. Pence, Grant Ramsey, Michelle M. Wirth

Faculty Publications

No abstract provided.


Staffan Müller-Wille And Hans-Jörg Rheinberger, A Cultural History Of Heredity, Charles H. Pence Jan 2013

Staffan Müller-Wille And Hans-Jörg Rheinberger, A Cultural History Of Heredity, Charles H. Pence

Faculty Publications

No abstract provided.


Aspen Status Report And Recommendation For The Book Cliffs, Paul C. Rogers, Cody M. Mittanck, Ronald J. Ryel Jan 2013

Aspen Status Report And Recommendation For The Book Cliffs, Paul C. Rogers, Cody M. Mittanck, Ronald J. Ryel

Aspen Bibliography

Regionally quaking aspen (Populus tremuloides Michx.) forests are experiencing numerous impediments to resilience. In the West, recent drought, fire suppression, insects, diseases, climate trends, inappropriate management, and ungulate herbivory are impacting these high biodiversity forests. We conducted a landscape assessment of aspen communities in the Book Cliffs region, Vernal Field Office of the Bureau of Land Management, for the purposes of determining landscape-level status of aspen and making recommendations for future management of these forests. The study area consists of 268 distinct aspen polygons totaling approximately 70 ha (174 acres) of aspen forest surrounded by much larger tracts of …


Book Cliffs Roadless Area Aspen Study 2013 : Grand & Uintah Counties, Utah, Cody M. Mittanck Jan 2013

Book Cliffs Roadless Area Aspen Study 2013 : Grand & Uintah Counties, Utah, Cody M. Mittanck

Aspen Bibliography

No abstract provided.


Genetic Diversity In Populations Of Epiphanes Chihuahuaensis (Rotifera: Monogononta) In The Northern Chihuahuan Desert, Diego E. Reyes Jan 2013

Genetic Diversity In Populations Of Epiphanes Chihuahuaensis (Rotifera: Monogononta) In The Northern Chihuahuan Desert, Diego E. Reyes

Open Access Theses & Dissertations

1. Cryptic speciation in zooplankton is a phenomenon that has been recently gaining much attention. This is due in part to advances in molecular techniques which help in the identification of morphologically indistinct species. Organisms that have been traditionally believed to have cosmopolitan distributions are being found to be composed of cryptic species complexes with high levels of genetic divergence among lineages.

2. Epiphanes chihuahuaensis is a member in the Epiphanes senta species complex. In a previous study by Schröder & Walsh (2007), genetic data, along with morphological and reproductive isolation data were employed to help delineate four species within …


The Causes And Consequences Of Individual Variation In Parental Care Behavior, Daniel P. Wetzel Jan 2013

The Causes And Consequences Of Individual Variation In Parental Care Behavior, Daniel P. Wetzel

Theses and Dissertations--Biology

Behavioral traits can be remarkably flexible depending on the conditions in which they are expressed, yet, in spite of this flexibility, persistent differences between individuals appear to limit the potential expression of behaviors. For example, despite evidence that parents provide variable amounts of parental care in response to changing environmental conditions, they also differ in the overall level of care they provide. I used a behavioral reaction norm approach to study individual variation in parental care behavior in free-living house sparrows (Passer domesticus). I investigated the nature of this variation by studying the relationship between different forms of …


Axolotl Paedomorphosis: A Comparison Of Juvenile, Metamorphic, And Paedomorphic Ambystoma Mexicanum Brain Gene Transcription, Carlena Johnson Jan 2013

Axolotl Paedomorphosis: A Comparison Of Juvenile, Metamorphic, And Paedomorphic Ambystoma Mexicanum Brain Gene Transcription, Carlena Johnson

Theses and Dissertations--Biology

Unlike many amphibians, the paedomorphic axolotl (Ambystoma mexicanum) rarely undergoes external morphological changes indicative of metamorphosis. However, internally, some axolotl tissues undergo cryptic metamorphic changes. A previous study examined interspecific patterns of larval brain gene expression and found that these species exhibited unique temporal expression patterns that were hypothesized to be morph specific. This thesis tested this hypothesis by examining differences in brain gene expression between juvenile (JUV), paedomorphic (PAED), and metamorphic (MET) axolotls. I identified 828 genes that were expressed differently between JUV, PAED, and MET. Expression estimates from JUV were compared to estimates from PAED and …


Genetic Diversity Of North American Captive-Born Gorillas (Gorilla Gorilla Gorilla), Noah D. Simmons, Ronald S. Wagner, Joseph G. Lorenz Jan 2013

Genetic Diversity Of North American Captive-Born Gorillas (Gorilla Gorilla Gorilla), Noah D. Simmons, Ronald S. Wagner, Joseph G. Lorenz

All Faculty Scholarship for the College of the Sciences

Western lowland gorillas (Gorilla gorilla gorilla) are designated as critically endangered and wild populations are dramatically declining as a result of habitat destruction, fragmentation, diseases (e.g., Ebola) and the illegal bushmeat trade. As wild populations continue to decline, the genetic management of the North American captive western lowland gorilla population will be an important component of the long‐term conservation of the species. We genotyped 26 individuals from the North American captive gorilla collection at 11 autosomal microsatellite loci in order to compare levels of genetic diversity to wild populations, investigate genetic signatures of a population bottleneck and identify …


Family Matters: An Analysis Of Genetic Relatedness Of Tetraclita Rubescens (The Pink Volcano Barnacle) Over Several Spatial Scales At Monterey And Bodega Bay, California, Kelly N. Chang Jan 2013

Family Matters: An Analysis Of Genetic Relatedness Of Tetraclita Rubescens (The Pink Volcano Barnacle) Over Several Spatial Scales At Monterey And Bodega Bay, California, Kelly N. Chang

Scripps Senior Theses

Inbreeding involves the mating of closely related individuals at a higher frequency than at random; this can decrease the average fitness of populations and individuals by reducing the presence of heterozygotes and augmenting the expression of deleterious genes. Since marine invertebrates exhibit widespread dispersal, their potential for inbreeding is often disregarded. The adult sessile state of barnacles creates the potential for inbreeding as a result of necessary copulation between neighboring individuals. Depending on the degree of mixing that occurs during dispersal, closely related individuals or siblings may settle in close proximity, generating the possibility of kin aggregation and consequent inbreeding. …


Diversification Under Sexual Selection: The Relative Roles Of Mate Preference Strength And The Degree Of Divergence In Mate Preferences, Rafael L. Rodríguez, Janette W. Boughman, David A. Gray, Eileen A. Hebets, Gerlinde Höbel, Laurel B. Symes Jan 2013

Diversification Under Sexual Selection: The Relative Roles Of Mate Preference Strength And The Degree Of Divergence In Mate Preferences, Rafael L. Rodríguez, Janette W. Boughman, David A. Gray, Eileen A. Hebets, Gerlinde Höbel, Laurel B. Symes

Eileen Hebets Publications

The contribution of sexual selection to diversification remains poorly understood after decades of research. This may be in part because studies have focused predominantly on the strength of sexual selection, which offers an incomplete view of selection regimes. By contrast, students of natural selection focus on environmental differences that help compare selection regimes across populations. To ask how this disparity in focus may affect the conclusions of evolutionary research, we relate the amount of diversification in mating displays to quantitative descriptions of the strength and the amount of divergence in mate preferences across a diverse set of case studies of …


Genetic Population Structure Of Us Atlantic Coastal Striped Bass (Morone Saxatilis), David T. Gauthier, Corinne A. Audemard, Jeanette E. L. Carlsson, Tanya L. Darden, Michael R. Denson, Kimberly S. Reece, Jens Carlsson Jan 2013

Genetic Population Structure Of Us Atlantic Coastal Striped Bass (Morone Saxatilis), David T. Gauthier, Corinne A. Audemard, Jeanette E. L. Carlsson, Tanya L. Darden, Michael R. Denson, Kimberly S. Reece, Jens Carlsson

Biological Sciences Faculty Publications

Genetic population structure of anadromous striped bass along the US Atlantic coast was analyzed using 14 neutral nuclear DNA microsatellites. Young-of-the-year and adult striped bass (n = 1114) were sampled from Hudson River, Delaware River, Chesapeake Bay, North Carolina, and South Carolina. Analyses indicated clear population structure with significant genetic differentiation between all regions. Global multilocus F-ST was estimated at 0.028 (P < 0.001). Population structure followed an isolation-by-distance model and temporal sampling indicated a stable population structure more than 2 years at all locations. Significant structure was absent within Hudson River, whereas weak but significant genetic differences were observed between northern and southern samples in Chesapeake Bay. The largest and smallest effective striped bass population sizes were found in Chesapeake Bay and South Carolina, respectively. Coalescence analysis indicated that the highest historical gene flow has been between Chesapeake Bay and Hudson River populations, and that exchange has not been unidirectional. Bayesian analysis of contemporary migration indicated that Chesapeake Bay serves as a major source of migrants for Atlantic coastal regions from Albemarle Sound northward. In addition to examining population genetic structure, the data acquired during this project were capable of serving as a baseline for assigning fish with unknown origin to source region.


The Effect Of Temperature On Seed Quality And Quantity In Crosses Between European (Populus Tremula) And Hybrid Aspens (P. Tremula X P. Tremuloides), L. Koviuranta, T. Latva-Karjanmaa, P. Pulkkinen Dec 2012

The Effect Of Temperature On Seed Quality And Quantity In Crosses Between European (Populus Tremula) And Hybrid Aspens (P. Tremula X P. Tremuloides), L. Koviuranta, T. Latva-Karjanmaa, P. Pulkkinen

Aspen Bibliography

Hybrid aspen (Populus tremula L. Populus tremuloides Michx.) plantations are expanding in Fennoscandia and the Baltic countries; however, the possible effects of plantations on the native European aspen (P. tremula) and the level of gene flow between European and hybrid aspen have not been investigated. We studied seed quantity and quality in intraspecific and interspecific crosses of the European and hybrid aspens over a two year period. In order to study whether elevated temperatures due to climate change would benefit the species differently, we performed the crosses in different temperatures. In both years, interspecific crosses produced more seeds with higher …


Effects Of Slash Pile Burning After Restoring Conifer- Encroached Aspen, Christa M. Dagley, John-Pascal Berrill, Stephanie Coppeto, Kyle Jacobson Dec 2012

Effects Of Slash Pile Burning After Restoring Conifer- Encroached Aspen, Christa M. Dagley, John-Pascal Berrill, Stephanie Coppeto, Kyle Jacobson

Aspen Bibliography

Removal of conifers encroaching aspen stands has been advocated and is being practiced in the Lake Tahoe Basin (EIP Project #10080: Aspen Community Restoration Projects). In remote and roadless areas, thinning of conifers is generating large volumes of wood and pile burning is currently being implemented to handle this biomass on site. However, the effects of pile burning on aspen are unknown, and there is an urgent need for guidelines to support design of thinning treatment prescriptions; specifically burn pile size and safe distances from live aspen trees of any size to prevent injury.


Genetic Diversity Of Neotropical Myotis (Chiroptera: Vespertilionidae) With An Emphasis On South American Species, Roxanne J. Larsen, Michelle C. Knapp, Hugh H. Genoways, Faisal Ali Anwarali Khan, Peter A. Larsen, Don E. Wilson, Robert J. Baker Oct 2012

Genetic Diversity Of Neotropical Myotis (Chiroptera: Vespertilionidae) With An Emphasis On South American Species, Roxanne J. Larsen, Michelle C. Knapp, Hugh H. Genoways, Faisal Ali Anwarali Khan, Peter A. Larsen, Don E. Wilson, Robert J. Baker

University of Nebraska State Museum: Mammalogy Papers

Background: Cryptic morphological variation in the Chiropteran genus Myotis limits the understanding of species boundaries and species richness within the genus. Several authors have suggested that it is likely there are unrecognized species-level lineages of Myotis in the Neotropics. This study provides an assessment of the diversity in New World Myotis by analyzing cytochrome-b gene variation from an expansive sample ranging throughout North, Central, and South America. We provide baseline genetic data for researchers investigating phylogeographic and phylogenetic patterns of Myotis in these regions, with an emphasis on South America.

Methodology and Principal Findings: Cytochrome-b sequences were generated and …


Phylogenetics Links Monster Larva To Deep-Sea Shrimp., Heather D Bracken-Grissom, Darryl L Felder, Nicole L Vollmer, Joel W Martin, Keith A Crandall Oct 2012

Phylogenetics Links Monster Larva To Deep-Sea Shrimp., Heather D Bracken-Grissom, Darryl L Felder, Nicole L Vollmer, Joel W Martin, Keith A Crandall

Computational Biology Institute

Mid-water plankton collections commonly include bizarre and mysterious developmental stages that differ conspicuously from their adult counterparts in morphology and habitat. Unaware of the existence of planktonic larval stages, early zoologists often misidentified these unique morphologies as independent adult lineages. Many such mistakes have since been corrected by collecting larvae, raising them in the lab, and identifying the adult forms. However, challenges arise when the larva is remarkably rare in nature and relatively inaccessible due to its changing habitats over the course of ontogeny. The mid-water marine species Cerataspis monstrosa (Gray 1828) is an armored crustacean larva whose adult identity …


Phylotranscriptomics To Bring The Understudied Into The Fold: Monophyletic Ostracoda, Fossil Placement, And Pancrustacean Phylogeny, Todd H. Oakley, Joanna M. Wolfe, Annie R. Lindgren, Alexander K. Zaharoff Sep 2012

Phylotranscriptomics To Bring The Understudied Into The Fold: Monophyletic Ostracoda, Fossil Placement, And Pancrustacean Phylogeny, Todd H. Oakley, Joanna M. Wolfe, Annie R. Lindgren, Alexander K. Zaharoff

Biology Faculty Publications and Presentations

An ambitious, yet fundamental goal for comparative biology is to understand the evolutionary relationships for all of life. However, many important taxonomic groups have remained recalcitrant to inclusion into broader scale studies. Here, we focus on collection of 9 new 454 transcriptome data sets from Ostracoda, an ancient and diverse group with a dense fossil record, which is often undersampled in broader studies. We combine the new transcriptomes with a new morphological matrix (including fossils) and existing expressed sequence tag, mitochondrial genome, nuclear genome, and ribosomal DNA data. Our analyses lead to new insights into ostracod and pancrustacean phylogeny. We …


A Tale Of Two Haplotypes: The Eda2r/Ar Intergenic Region Is The Most Divergent Genomic Segment Between Africans And East Asians In The Human Genome, Amanda M. Casto, Brenna M. Henn, Jeffery M. Kidd, Carlos D. Bustamante, Marcus W. Feldman Sep 2012

A Tale Of Two Haplotypes: The Eda2r/Ar Intergenic Region Is The Most Divergent Genomic Segment Between Africans And East Asians In The Human Genome, Amanda M. Casto, Brenna M. Henn, Jeffery M. Kidd, Carlos D. Bustamante, Marcus W. Feldman

Human Biology Open Access Pre-Prints

Single nucleotide polymorphisms (SNPs) with large allele frequency differences between human populations are relatively rare. The longest run of SNPs with an allele frequency difference of one between the Yoruba of Nigeria and the Han Chinese is found on the long arm of the X chromosome in the intergenic region separating the EDA2R and AR genes. It has been proposed that the unusual allele frequency distributions of these SNPs are the result of a selective sweep affecting African populations that occurred after the Out-of-Africa migration. To investigate the evolutionary history of the EDA2R/AR intergenic region, we characterized the haplotype structure …


Comparative Phylogeography Of Central African Duikers Using Non-Invasive Sampling Methods, Stephan Ntie Aug 2012

Comparative Phylogeography Of Central African Duikers Using Non-Invasive Sampling Methods, Stephan Ntie

LSU New Orleans Theses and Dissertations

The present study sets out to assess patterns of evolutionary diversification in central African duikers (subfamily Cephalophinae). The sampling strategy consisted of collecting geo-referenced duiker feces across 43 sites and seven countries. However, several challenges related to the use of non-invasive samples needed to be addressed prior to large scale DNA amplification. First, the best storage method for obtaining DNA from fecal samples needed to be established. Our study revealed that while silica is best for nuclear microsatellite analyses, RNAlater is the best storage medium for maximal mitochondrial amplification. Moreover, extracting DNA as early as possible always provided the …


Evolution Of Nuclear Integrations Of The Mitochondrial Genome In Great Apes And Their Potential As Molecular Markers, Ivan D. Soto-Calderon Aug 2012

Evolution Of Nuclear Integrations Of The Mitochondrial Genome In Great Apes And Their Potential As Molecular Markers, Ivan D. Soto-Calderon

LSU New Orleans Theses and Dissertations

The mitochondrial control region (MCR) has played an important role as a population genetic marker in many taxa but sequencing of complete eukaryotic genomes has revealed that nuclear integrations of mitochondrial DNA (numts) are abundant and widespread across many taxa. If left undetected, numts can inflate mitochondrial diversity and mislead interpretation of phylogenetic relationships. Comparative analyses of complete genomes in humans, orangutans and chimpanzees, and preliminary studies in gorillas have revealed high numt prevalence in great apes, but rigorous comparative analyses across taxa have been lacking.

The present study aimed to systematically compare the evolutionary dynamics of MCR numts in …


A Genetic Survey Of English Sole Populations In The Salish Sea, Elizabeth S. Gutierrez, Gary A. Winans, Jon Baker, Amanda Cope Aug 2012

A Genetic Survey Of English Sole Populations In The Salish Sea, Elizabeth S. Gutierrez, Gary A. Winans, Jon Baker, Amanda Cope

STAR Program Research Presentations

This summer I interned at the Northwest Fisheries Science Center in Seattle, WA and participated in NOAA’s Salish Sea Project. The Salish Sea Project’s goal is to identify genetically distinctive groups of species in the Salish Sea that may have unique evolutionary and/or adaptive backgrounds. These findings will allow NOAA to promote and monitor the natural production of species in the Salish Sea, to select representative populations for experimental work regarding pollution, ocean acidification and climate change, to contribute to managing the ecosystem for intra- and inter-species diversity, and to help make informed decisions about adaptive management and marine protected …


Selaginella Moellendorffii Telomeres: Conserved And Unique Features In An Ancient Land Plant Lineage, Eugene V. Shakirov, Dorothy E. Shippen Jul 2012

Selaginella Moellendorffii Telomeres: Conserved And Unique Features In An Ancient Land Plant Lineage, Eugene V. Shakirov, Dorothy E. Shippen

Biological Sciences Faculty Research

Telomeres, the essential terminal regions of linear eukaryotic chromosomes, consist of G-rich DNA repeats bound by a plethora of associated proteins. While the general pathways of telomere maintenance are evolutionarily conserved, individual telomere complex components show remarkable variation between eukaryotic lineages and even within closely related species. The recent genome sequencing of the lycophyte Selaginella moellendorffii and the availability of an ever-increasing number of flowering plant genomes provides a unique opportunity to evaluate the molecular and functional evolution of telomere components from the early evolving non-seed plants to the more developmentally advanced angiosperms. Here we analyzed telomere sequence in S. …


Facilitation Drives Mortality Patterns Along Succession Gradients Of Aspen-Conifer Forests, W. John Calder, Samuel B. St. Clair Jun 2012

Facilitation Drives Mortality Patterns Along Succession Gradients Of Aspen-Conifer Forests, W. John Calder, Samuel B. St. Clair

Aspen Bibliography

While it is well established that facilitation and competition are important structuring forces in plant communities, a clear understanding of the interactions between them and how they change through the life stages of plants and affect long-term plant community development is lacking. We have observed that conifer seedlings are rarely found growing in meadows but readily establish under adjacent aspen stands, particularly at the base of aspen trees, creating the potential for antagonistic interactions in later life stages. To examine these relationships and their potential consequences on forest community development, we characterized patterns of establishment, regeneration, and overstory mortality of …


Two Boundaries Separate Borrelia Burgdorferi Populations In North America, Gabriele Margos, Jean I. Tsao, Santiago Castillo-Ramirez, Yvette A. Girard, Anne G. Hoen Jun 2012

Two Boundaries Separate Borrelia Burgdorferi Populations In North America, Gabriele Margos, Jean I. Tsao, Santiago Castillo-Ramirez, Yvette A. Girard, Anne G. Hoen

Dartmouth Scholarship

Understanding the spread of infectious diseases is crucial for implementing effective control measures. For this, it is important to obtain information on the contemporary population structure of a disease agent and to infer the evolutionary processes that may have shaped it. Here, we investigate on a continental scale the population structure of Borrelia burgdorferi, the causative agent of Lyme borreliosis (LB), a tick-borne disease, in North America. We test the hypothesis that the observed d population structure is congruent with recent population expansions and that these were preceded by bottlenecks mostly likely caused by the near extirpation in the 1900s …


Composition Of The Adult Digestive Tract Bacterial Microbiome Based On Seven Mouth Surfaces, Tonsils, Throat And Stool Samples, Nicola Segata, Susan Kinder Haake, Peter Mannon, Katherine P. Lemon, Levi Waldron, Dirk Gevers, Curtis Huttenhower, Jacques Izard Jun 2012

Composition Of The Adult Digestive Tract Bacterial Microbiome Based On Seven Mouth Surfaces, Tonsils, Throat And Stool Samples, Nicola Segata, Susan Kinder Haake, Peter Mannon, Katherine P. Lemon, Levi Waldron, Dirk Gevers, Curtis Huttenhower, Jacques Izard

Department of Food Science and Technology: Faculty Publications

Background: To understand the relationship between our bacterial microbiome and health, it is essential to define the microbiome in the absence of disease. The digestive tract includes diverse habitats and hosts the human body’s greatest bacterial density. We describe the bacterial community composition of ten digestive tract sites from more than 200 normal adults enrolled in the Human Microbiome Project, and metagenomically determined metabolic potentials of four representative sites.

Results: The microbiota of these diverse habitats formed four groups based on similar community compositions: buccal mucosa, keratinized gingiva, hard palate; saliva, tongue, tonsils, throat; sub- and supra-gingival plaques; …