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Full-Text Articles in Life Sciences

Classification Of Planetary Craters Using Outline-Based Morphometrics, Thomas J. Slezak, Jani Radebaugh, Eric H. Christiansen, Mark C. Belk Nov 2020

Classification Of Planetary Craters Using Outline-Based Morphometrics, Thomas J. Slezak, Jani Radebaugh, Eric H. Christiansen, Mark C. Belk

Faculty Publications

The morphologies of craters on planetary surfaces reveal clues about the geologic mechanisms by which they originate and subsequently evolve, as well as the materials and physical variables inherent to the environment in which they formed. We carried out a quantitative multivariate analysis of shape descriptors derived from the outlines of craters formed by volcanic processes on Mars, Io, and Earth and by impact cratering on the Moon using elliptic Fourier analysis (EFA) and the Zahn-Roskies (Z-R) shape function. Canonical variate analysis (CVA) was used to construct a statistical model of differences between the crater groups to classify …


Predators As Agents Of Selection And Diversification, Jerald B. Johnson, Mark C. Belk Oct 2020

Predators As Agents Of Selection And Diversification, Jerald B. Johnson, Mark C. Belk

Faculty Publications

Predation is ubiquitous in nature and can be an important component of both ecological and evolutionary interactions. One of the most striking features of predators is how often they cause evolutionary diversification in natural systems. Here, we review several ways that this can occur, exploring empirical evidence and suggesting promising areas for future work. We also introduce several papers recently accepted in Diversity that demonstrate just how important and varied predation can be as an agent of natural selection. We conclude that there is still much to be done in this field, especially in areas where multiple predator species prey …


Morphometric Response Of Galaxias Maculatus (Jenyns) To Lake Colonization In Chile, Margaret Mercer, Peter C. Searle, Roberto Cifuentes, Evelyn Habit, Mark C. Belk May 2020

Morphometric Response Of Galaxias Maculatus (Jenyns) To Lake Colonization In Chile, Margaret Mercer, Peter C. Searle, Roberto Cifuentes, Evelyn Habit, Mark C. Belk

Faculty Publications

Body and head shape in fish responds to environmental factors such as water flow rate, food sources, and niche availability. However, the way in which fish respond to these environmental factors varies. In Central Chile, multiple river and lake systems along the coast provide an ideal study site to investigate these types of shape changes. We use geometric morphometrics to characterize shape differences in Galaxias maculatus (Jenyns) between river and lake populations. Lake fish converge on a shape with a more fusiform body, narrower head, and larger eyes, while river fish have a more robust body, rounder head, and smaller …


Life History Divergence In Livebearing Fishes In Response To Predation: Is There A Microevolution To Macroevolution Barrier?, Mark C. Belk, Spencer J. Ingley, Jerald B. Johnson May 2020

Life History Divergence In Livebearing Fishes In Response To Predation: Is There A Microevolution To Macroevolution Barrier?, Mark C. Belk, Spencer J. Ingley, Jerald B. Johnson

Faculty Publications

A central problem in evolutionary biology is to determine whether adaptive phenotypic variation within species (microevolution) ultimately gives rise to new species (macroevolution). Predation environment can select for trait divergence among populations within species. The implied hypothesis is that the selection resulting from predation environment that creates population divergence within species would continue across the speciation boundary such that patterns of divergence after speciation would be a magnified accumulation of the trait variation observed before speciation. In this paper, we test for congruence in the mechanisms of microevolution and macroevolution by comparing the patterns of life history divergence among three …


Effects Of Substrate On Movement Patterns And Behavior Of Stream Fish Through Culverts: An Experimental Approach, Kyla Johnson, Lindsay E. Wait, Suzanne K. Monk, Russell Rader, Rollin H. Hotchkiss, Mark C. Belk Jan 2019

Effects Of Substrate On Movement Patterns And Behavior Of Stream Fish Through Culverts: An Experimental Approach, Kyla Johnson, Lindsay E. Wait, Suzanne K. Monk, Russell Rader, Rollin H. Hotchkiss, Mark C. Belk

Faculty Publications

Culverts can provide a significant barrier to fish passage by fragmenting fish habitats and impeding the passage success of small-bodied fish. Geographical connectivity is critical to the maintenance of diverse fish assemblages. Culverts with high cross-sectional velocity can cause population fragmentation by impeding passage of small, freshwater fish. Behavioral responses of small fish to high velocities can differ among functional groups, and swimming behavior of many species is not well known. We tested effects of substrate type on swimming behavior in two small, freshwater fish species—southern leatherside chub (Lepidomeda aliciae, a midwater species), and longnose dace (Rhinichthys …


Does Body Size Affect Fitness The Same Way In Males And Females? A Test Of Multiple Fitness Components, Ashlee N. Smith, Mark C. Belk Mar 2018

Does Body Size Affect Fitness The Same Way In Males And Females? A Test Of Multiple Fitness Components, Ashlee N. Smith, Mark C. Belk

Faculty Publications

Body size generally has an important relationship with fitness, whereby larger body size leads to an increase in fitness through competition, reproductive output and survivorship. However, the traits through which body size increases fitness often differ between the sexes. We tested for the effects of body size on fitness in both sexes using three separate experiments on competitive ability, reproductive output and starvation resistance in the burying beetle Nicrophorus marginatus. Results varied between sexes as follows: (1) larger body size increased competitive ability differentially between sexes; (2) female body size, but not male body size, significantly affected reproductive output …


Why Does It Take Two To Tango? Lifetime Fitness Consequences Of Parental Care In A Burying Beetle, Ashlee N. Smith, J. Curtis Creighton, Mark C. Belk Oct 2017

Why Does It Take Two To Tango? Lifetime Fitness Consequences Of Parental Care In A Burying Beetle, Ashlee N. Smith, J. Curtis Creighton, Mark C. Belk

Faculty Publications

In species that require parental care, each parent can either care for their offspring or leave them in the care of the other parent. For each parent this creates three possible parental care strategies: biparental care, uniparental (male or female) care, and uniparental desertion by either the male or female. The burying beetle, Nicrophorus orbicollis, typically exhibits biparental care of offspring, and thus provides a unique system that allows us to compare the fitness benefits of these parental care strategies in an unconfounded way. In this study, we assess the lifetime fitness of biparental care, uniparental care, and uniparental …


Interaction Between Predation Environment And Diet Constrains Body Shape In Utah Chub, Gila Atraria (Cypriniformes: Cyprinidae), Trevor J. Williams, Jerald B. Johnson, Mark C. Belk Jun 2017

Interaction Between Predation Environment And Diet Constrains Body Shape In Utah Chub, Gila Atraria (Cypriniformes: Cyprinidae), Trevor J. Williams, Jerald B. Johnson, Mark C. Belk

Faculty Publications

Evolution typically occurs in response to a suite of selective pressures. Yet, many studies of natural selection in the wild only investigate a single selective agent at a time. This can be problematic when selective agents act in non-additive ways. Here we evaluate the interactive effects of diet and predation on the evolution of body shape in the cyprinid fish Utah chub (Gila atraria). We found that both factors and the interaction between them are significant predictors of body shape. This interaction is likely a result of different forms of selective pressures, where predation is a stabilizing selective …


Different Roads Lead To Rome: Integrative Taxonomic Approaches Lead To The Discovery Of Two New Lizard Lineages In The Liolaemus Montanus Group (Squamata: Liolaemidae), Cesar Aguilar, Perry L. Wood Jr., Mark C. Belk, Mike H. Duff, Jack W. Sites Jr. Sep 2016

Different Roads Lead To Rome: Integrative Taxonomic Approaches Lead To The Discovery Of Two New Lizard Lineages In The Liolaemus Montanus Group (Squamata: Liolaemidae), Cesar Aguilar, Perry L. Wood Jr., Mark C. Belk, Mike H. Duff, Jack W. Sites Jr.

Faculty Publications

Integrative taxonomy (IT) is becoming a preferred approach to delimiting species boundaries by including different empirical criteria. IT methods can be divided into two types of procedures both of which use multiple kinds of evidence: step-by-step approaches test hypotheses by sequential evaluation in a hypothetic-deductive framework, while model-based procedures delimit groups based on statistical information criteria. In this study we used a step-by-step approach and a Gaussian clustering (GC) method to test species boundaries in the northernmost species of the Liolaemus montanus group. We used different methods based on mitochondrial and nuclear DNA sequence data, morphological measures and niche envelope …


Does Habitat Restoration Increase Coexistence Of Native Stream Fishes With Introduced Brown Trout: A Case Study On The Middle Provo River, Utah, Usa, Mark C. Belk, Eric J. Billman, Craig Ellsworth, Brock R. Mcmillan Mar 2016

Does Habitat Restoration Increase Coexistence Of Native Stream Fishes With Introduced Brown Trout: A Case Study On The Middle Provo River, Utah, Usa, Mark C. Belk, Eric J. Billman, Craig Ellsworth, Brock R. Mcmillan

Faculty Publications

Restoration of altered or degraded habitats is often a key component in the conservation plan of native aquatic species, but introduced species may influence the response of the native community to restoration. Recent habitat restoration of the middle section of the Provo River in central Utah, USA, provided an opportunity to evaluate the effect of habitat restoration on the native fish community in a system with an introduced, dominant predator—brown trout (Salmo trutta). To determine the change in distribution of fish species and community composition, we surveyed 200 m of each of the four study reaches both before …


Differences In Patterns Of Reproductive Allocation Between The Sexes In Nicrophorus Orbicollis, Ashlee N. Smith, J. Curtis Creighton, Mark C. Belk Nov 2015

Differences In Patterns Of Reproductive Allocation Between The Sexes In Nicrophorus Orbicollis, Ashlee N. Smith, J. Curtis Creighton, Mark C. Belk

Faculty Publications

Organisms are selected to maximize lifetime reproductive success by balancing the costs of current reproduction with costs to future survival and fecundity. Males and females typically face different reproductive costs, which makes comparisons of their reproductive strategies difficult. Burying beetles provide a unique system that allows us to compare the costs of reproduction between the sexes because males and females are capable of raising offspring together or alone and carcass preparation and offspring care represent the majority of reproductive costs for both sexes. Because both sexes perform the same functions of carcass preparation and offspring care, we predict that they …


Metazoan Parasites Of Antarctic Fishes, Mehmet Cemal Oğuz, Yahya Tepe, Mark C. Belk, Richard A. Heckmann, Burçak Aslan, Meryem Gürgen, Rodney A. Bray, Ülker Akgül Jan 2015

Metazoan Parasites Of Antarctic Fishes, Mehmet Cemal Oğuz, Yahya Tepe, Mark C. Belk, Richard A. Heckmann, Burçak Aslan, Meryem Gürgen, Rodney A. Bray, Ülker Akgül

Faculty Publications

To date, there have been nearly 100 papers published on metazoan parasites of Antarctic fishes, but there has not yet been any compilation of a species list of fish parasites for this large geographic area. Herein, we provide a list of all documented occurrences of monogenean, cestode, digenean, acanthocephalan, nematode, and hirudinean parasites of Antarctic fishes. The list includes nearly 250 parasite species found in 142 species of host fishes. It is likely that there are more species of fish parasites, which are yet to be documented from Antarctic waters.


Viability Costs Of Reproduction And Behavioral Compensation In Western Mosquitofish (Gambusia Affinis), Clinton T. Laidlaw, Jacob M. Condon, Mark C. Belk Nov 2014

Viability Costs Of Reproduction And Behavioral Compensation In Western Mosquitofish (Gambusia Affinis), Clinton T. Laidlaw, Jacob M. Condon, Mark C. Belk

Faculty Publications

The cost of reproduction hypothesis suggests that current reproduction has inherent tradeoffs with future reproduction. These tradeoffs can be both in the form of energy allocated to current offspring as opposed to somatic maintenance and future reproduction (allocation costs), or as an increase in mortality as a result of morphological or physiological changes related to reproduction (viability costs). Individuals may be able to decrease viability costs by altering behavior. Female western mosquitofish, Gambusia affinis experience a reduction in swimming ability as a consequence of pregnancy. We test for a viability cost of reproduction, and for behavioral compensation in pregnant female …


Residency Time As An Indicator Of Reproductive Restraint In Male Burying Beetles, Ashlee N. Smith, Mark C. Belk, J. Curtis Creighton Oct 2014

Residency Time As An Indicator Of Reproductive Restraint In Male Burying Beetles, Ashlee N. Smith, Mark C. Belk, J. Curtis Creighton

Faculty Publications

The cost of reproduction theory posits that there are trade-offs between current and future reproduction because resources that are allocated to current offspring cannot be used for future reproductive opportunities. Two adaptive reproductive strategies have been hypothesized to offset the costs of reproduction and maximize lifetime fitness. The terminal investment hypothesis predicts that as individuals age they will allocate more resources to current reproduction as a response to decreasing residual reproductive value. The reproductive restraint hypotheses predicts that as individuals age they will allocate fewer resources to current reproduction to increase the chance of surviving for an additional reproductive opportunity. …


Prior Experience Affects Allocation To Current Reproduction In A Burying Beetle, Eric J. Billman, J. Curtis Creighton, Mark C. Belk Apr 2014

Prior Experience Affects Allocation To Current Reproduction In A Burying Beetle, Eric J. Billman, J. Curtis Creighton, Mark C. Belk

Faculty Publications

The cost of reproduction hypothesis predicts that the level of reproductive investment to current reproduction is constrained by an individual’s future reproductive potential or residual reproductive value. Therefore, age, or differences between young and old individuals in residual reproductive value, is expected to influence reproductive investment. However, recent theoretical work suggests that residual reproductive value is also influenced by an individual’s state or condition which may in part be determined by prior reproductive experience. We evaluated the reproductive investment of same-aged female burying beetles (Nicrophorus orbicollis) to determine how prior reproductive experience affects current reproduction. Consistent with previous …


Morphological Divergence Driven By Predation Environment Within And Between Species Of Brachyrhaphis Fishes, Spencer J. Ingley, Eric J. Billman, Mark C. Belk, Jerald B. Johnson Feb 2014

Morphological Divergence Driven By Predation Environment Within And Between Species Of Brachyrhaphis Fishes, Spencer J. Ingley, Eric J. Billman, Mark C. Belk, Jerald B. Johnson

Faculty Publications

Natural selection often results in profound differences in body shape among populations from divergent selective environments. Predation is a well-studied driver of divergence, with predators having a strong effect on the evolution of prey body shape, especially for traits related to escape behavior. Comparative studies, both at the population level and between species, show that the presence or absence of predators can alter prey morphology. Although this pattern is well documented in various species or population pairs, few studies have tested for similar patterns of body shape evolution at multiple stages of divergence within a taxonomic group. Here, we examine …


Orientocreadium Batrachoides Tubangui, 1931 (Orientocreadiidae): The Only Trematode Parasite Of Clarias Gariepinus (Burchell, 1822) (Clariidae) From The Asi River (Southern Turkey), Tayha Tepe, Mehmet Cemal Oğuz, Mark C. Belk, Remzi Özgen Jan 2013

Orientocreadium Batrachoides Tubangui, 1931 (Orientocreadiidae): The Only Trematode Parasite Of Clarias Gariepinus (Burchell, 1822) (Clariidae) From The Asi River (Southern Turkey), Tayha Tepe, Mehmet Cemal Oğuz, Mark C. Belk, Remzi Özgen

Faculty Publications

Objective: Some information is available about the parasite fauna and incidence for Clarias gariepinus in Turkey, but digenean parasites have received little attention. The purpose of the study is to contribute to the parasite fauna of Turkey.

Methods: From 2007 to 2008, a total 63 Clarias gariepinus that were caught in the Asi River were purchased from the fish market in Hatay and brought on ice to the Parasitology Research Laboratory at Atatürk University. The fish were dissected. The obtained parasites were fixed with AFA, dyed with Mayer’s Carmalum, and mounted with Canada Balsam.

Results: Forty-eight fish were infected with …


Dispersal Behavior Correlates With Personality Of A North American Fish, Josh E. Rasmussen, Mark C. Belk Apr 2012

Dispersal Behavior Correlates With Personality Of A North American Fish, Josh E. Rasmussen, Mark C. Belk

Faculty Publications

The process of dispersal is determined by the interaction of individual (intrinsic) traits and environmental (extrinsic) factors. Although many studies address and quantify dispersal, few evaluate both intrinsic and extrinsic factors jointly. We test the relative importance of intrinsic traits (exploration tendency and size) and extrinsic factors (population density and habitat quality) on dispersal of a medium-sized western United States minnow, southern leatherside chub Lepidomeda aliciae. A generalized linear model with a binomial response was used to determine the probability of individuals dispersing one year after tagging. Medium-sized individuals that were more prone to explore novel environments were 10.7 …


Morphological Convergence During Pregnancy Among Predator And Nonpredator Populations Of The Livebearing Fish Brachyrhaphis Rhabdophora (Teleostei: Poeciliidae), Jeff S. Wesner, Eric J. Billman, Adam Meier, Mark C. Belk Apr 2011

Morphological Convergence During Pregnancy Among Predator And Nonpredator Populations Of The Livebearing Fish Brachyrhaphis Rhabdophora (Teleostei: Poeciliidae), Jeff S. Wesner, Eric J. Billman, Adam Meier, Mark C. Belk

Faculty Publications

Predation can drive morphological divergence in prey populations, although examples of divergent selection are typically limited to nonreproductive individuals. In livebearing females, shape often changes drastically during pregnancy, reducing speed and mobility and enhancing susceptibility to predation. In the present study, we document morphological divergence among populations of nonreproductive female livebearing fish (Brachyrhaphis rhabdophora) in predator and nonpredator environments. We then test the hypothesis that shape differences among nonreproductive females are maintained among reproductive females between predator and nonpredator environments. Nonreproductive females in predator environments had larger caudal regions and more fusiform bodies than females in nonpredator environments; …


Environmental Dna Sequencing Primers For Eutardigrades And Bdelloid Rotifers, Byron J. Adams, Jeremy Whiting, Elizabeth K. Costello, Kristen R. Freeman, Andrew P. Martin, Michael S. Robeson, Steve K. Schmidt Dec 2009

Environmental Dna Sequencing Primers For Eutardigrades And Bdelloid Rotifers, Byron J. Adams, Jeremy Whiting, Elizabeth K. Costello, Kristen R. Freeman, Andrew P. Martin, Michael S. Robeson, Steve K. Schmidt

Faculty Publications

Background: The time it takes to isolate individuals from environmental samples and then extract DNA from each individual is one of the problems with generating molecular data from meiofauna such as eutardigrades and bdelloid rotifers. The lack of consistent morphological information and the extreme abundance of these classes makes morphological identification of rare, or even common cryptic taxa a large and unwieldy task. This limits the ability to perform large-scale surveys of the diversity of these organisms. Here we demonstrate a culture-independent molecular survey approach that enables the generation of large amounts of eutardigrade and bdelloid rotifer sequence data directly …


Differential Mortality Drives Life-History Evolution And Population Dynamics In The Fish Brachyrhaphis Rhabdophora, Jerald B. Johnson, J. Jaime Zuniga-Vega Aug 2009

Differential Mortality Drives Life-History Evolution And Population Dynamics In The Fish Brachyrhaphis Rhabdophora, Jerald B. Johnson, J. Jaime Zuniga-Vega

Faculty Publications

Life-history theory predicts that populations experiencing different levels of extrinsic mortality will evolve divergent reproductive strategies. Previous work in the live bearing fish Brachyrhaphis rhabdophora shows that individuals from populations that occur with piscivorous fish mature earlier and at smaller sizes and have more and smaller offspring than fish from populations without predators. However, until now, there have been no data to demonstrate that differences in mortality rates actually exist between predator and predator free sites. Here we present the results of a serial mark-recapture field study designed to estimate mortality rates in natural populations of B. rhabodophora from Costa …


Transcriptomic Analysis Of The Entomopathogenic Nematode Heterorhabditis Bacteriophora Tto1, Byron J. Adams, Xiaodong Bai, Todd A. Ciche, Sandra Clifton, Randy Gaugler, Parwinder S. Grewal, Saskia A. Hogenhout, John Spieth, Paul W. Sternberg, Richard K. Wilson Apr 2009

Transcriptomic Analysis Of The Entomopathogenic Nematode Heterorhabditis Bacteriophora Tto1, Byron J. Adams, Xiaodong Bai, Todd A. Ciche, Sandra Clifton, Randy Gaugler, Parwinder S. Grewal, Saskia A. Hogenhout, John Spieth, Paul W. Sternberg, Richard K. Wilson

Faculty Publications

Background: The entomopathogenic nematode Heterorhabditis bacteriophora and its symbiotic bacterium, Photorhabdus luminescens, are important biological control agents of insect pests. This nematode-bacterium-insect association represents an emerging tripartite model for research on mutualistic and parasitic symbioses. Elucidation of mechanisms underlying these biological processes may serve as a foundation for improving the biological control potential of the nematode-bacterium complex. This large-scale expressed sequence tag (EST) analysis effort enables gene discovery and development of microsatellite markers. These ESTs will also aid in the annotation of the upcoming complete genome sequence of H. bacteriophora. Results: A total of 31,485 high quality ESTs were generated …


Desiccation Survival In An Antarctic Nematode: Molecular Analysis Using Expressed Sequenced Tags, Byron J. Adams, Bishwo N. Adhikari, Diana H. Wall Feb 2009

Desiccation Survival In An Antarctic Nematode: Molecular Analysis Using Expressed Sequenced Tags, Byron J. Adams, Bishwo N. Adhikari, Diana H. Wall

Faculty Publications

Background: Nematodes are the dominant soil animals in Antarctic Dry Valleys and are capable of surviving desiccation and freezing in an anhydrobiotic state. Genes induced by desiccation stress have been successfully enumerated in nematodes; however we have little knowledge of gene regulation by Antarctic nematodes which can survive multiple environmental stresses. To address this problem we investigated the genetic responses of a nematode species, Plectus murrayi, that is capable of tolerating Antarctic environmental extremes, in particular desiccation and freezing. In this study, we provide the first insight into the desiccation induced transcriptome of an Antarctic nematode through cDNA library construction …


Calculating Expected Dna Remnants From Ancient Founding Events In Human Population Genetics, Nathan C. Sheffield, Keith A. Crandall, Andrew Stacey Oct 2008

Calculating Expected Dna Remnants From Ancient Founding Events In Human Population Genetics, Nathan C. Sheffield, Keith A. Crandall, Andrew Stacey

Faculty Publications

Background- Recent advancements in sequencing and computational technologies have led to rapid generation and analysis of high quality genetic data. Such genetic data have achieved wide acceptance in studies of historic human population origins and admixture. However, in studies relating to small, recent admixture events, genetic factors such as historic population sizes, genetic drift, and mutation can have pronounced effects on data reliability and utility. To address these issues we conducted genetic simulations targeting influential genetic parameters in admixed populations. Results- We performed a series of simulations, adjusting variable values to assess the affect of these genetic parameters on current …


Many Species In One: Dna Barcoding Overestimates The Number Of Species When Nuclear Mitochondrial Pseudogenes Are Coamplified, Michael F. Whiting, Hojun Song, Keith A. Crandall, Jennifer E. Buhay Sep 2008

Many Species In One: Dna Barcoding Overestimates The Number Of Species When Nuclear Mitochondrial Pseudogenes Are Coamplified, Michael F. Whiting, Hojun Song, Keith A. Crandall, Jennifer E. Buhay

Faculty Publications

Nuclear mitochondrial pseudogenes (numts) are nonfunctional copies of mtDNA in the nucleus that have been found in major clades of eukaryotic organisms.


Double-Stranded Rna-Activated Protein Kinase Pkr Of Fishes And Amphibians: Varying The Number Of Double-Stranded Rna Binding Domains And Lineage-Specific Duplications, Loubna Tazi, Stefan Rothenburg, Nikolaus Deigendesch, Madhusudan Dey, Thomas E. Dever Mar 2008

Double-Stranded Rna-Activated Protein Kinase Pkr Of Fishes And Amphibians: Varying The Number Of Double-Stranded Rna Binding Domains And Lineage-Specific Duplications, Loubna Tazi, Stefan Rothenburg, Nikolaus Deigendesch, Madhusudan Dey, Thomas E. Dever

Faculty Publications

Double-stranded (ds) RNA, generated during viral infection, binds and activates the mammalian anti-viral protein kinase PKR, which phosphorylates the translation initiation factor eIF2alpha leading to the general inhibition of protein synthesis. Although PKR-like activity has been described in fish cells, the responsible enzymes eluded molecular characterization until the recent discovery of goldfish and zebrafish PKZ, which contain Z-DNA-binding domains instead of dsRNA-binding domains (dsRBDs). Fish and amphibian PKR genes have not been described so far. Results- Here we report the cloning and identification of 13 PKR genes from 8 teleost fish and amphibian species, including zebrafish, demonstrating the coexistence of …


Distinguishing Importation From Diversification Of Quinolone-Resistant Neisseria Gonorrhoeae By Molecular Evolutionary Analysis, Keith A. Crandall, Marcos Perez-Losada, Margaret C. Bash, Michael Dan, Jonathan Zenilman, Raphael P. Viscidi Jun 2007

Distinguishing Importation From Diversification Of Quinolone-Resistant Neisseria Gonorrhoeae By Molecular Evolutionary Analysis, Keith A. Crandall, Marcos Perez-Losada, Margaret C. Bash, Michael Dan, Jonathan Zenilman, Raphael P. Viscidi

Faculty Publications

Distinguishing the recent introduction of quinolone resistant gonococci into a population from diversification of resistant strains already in the population is important for planning effective infection control strategies. We applied molecular evolutionary analyses to DNA sequences from 9 housekeeping genes and gyrA, parC and porB of 24 quinolone resistant N. gonorrhoeae (QRNG) and 24 quinolone sensitive isolates collected in Israel during 2000-2001. Results- Phylogenetic and eBURST analyses and estimates of divergence time indicated QRNG were introduced on 3 separate occasions and underwent limited diversification by mutation, deletion and horizontal gene transfer. Reconstruction of N. gonorrhoeae demography showed a slowly declining …


Biological Status Of Leatherside Chub: A Framework For Conservation Of Western Freshwater Fishes, Mark C. Belk, Jerald B. Johnson Jan 2007

Biological Status Of Leatherside Chub: A Framework For Conservation Of Western Freshwater Fishes, Mark C. Belk, Jerald B. Johnson

Faculty Publications

Outside of anadromous salmonids and a few endangered species, biology of native freshwater fishes of western North America is poorly known. What do we need to know to effectively manage native species and avoid decline and extinction? A recent analysis of the role of science in the Pacific salmon controversy outlines a clear framework for biological evaluation and management of native species. This framework has three components: (1) determine status of populations based on genetic and ecological variation, (2) identify and quantify threats to populations, and (3) determine actions to alleviate threats and promote conservation of populations. We use our …


Threatened Fishes Of The World: Percilia Irwini (Eigenmann 1927) (Perciliidae), Evelyn Habit, Mark C. Belk Jan 2007

Threatened Fishes Of The World: Percilia Irwini (Eigenmann 1927) (Perciliidae), Evelyn Habit, Mark C. Belk

Faculty Publications

Common name: Carmelita de Concepcion (Spanish).


A Hydrothermal After-Ripening Time Model For Seed Dormancy Loss In Bromus Tectorum L., Phil S. Allen, Necia B. Bair Mar 2006

A Hydrothermal After-Ripening Time Model For Seed Dormancy Loss In Bromus Tectorum L., Phil S. Allen, Necia B. Bair

Faculty Publications

After-ripening, the loss of dormancy under dry conditions, is associated with a decrease in mean base water potential for germination of Bromus tectorum L. seeds. After-ripening rate is a linear function of temperature above a base temperature, so that dormancy loss can be quantified using a thermal after-ripening time (TAR) model. To incorporate storage water potential into TAR, we created a hydrothermal after-ripening time (HTAR) model. Seeds from two B. tectorum populations were stored under controlled temperatures (20 or 30° C) and water potentials (400 to 40MPa). Subsamples were periodically removed from each storage treatment and incubated at 15 or …