Genetics Commons^™

Resolution By Unassisted Top3 Points To Template Switch Recombination Intermediates During Dna Replication, M. Rebecca Glineburg, Alejandro Chavez, Vishesh Agrawal, Steven J. Brill, F. Brad Johnson

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The evolutionarily conserved Sgs1/Top3/Rmi1 (STR) complex plays vital roles in DNA replication and repair. One crucial activity of the complex is dissolution of toxic X-shaped recombination intermediates that accumulate during replication of damaged DNA. However, despite several years of study the nature of these X-shaped molecules remains debated. Here we use genetic approaches and two-dimensional gel electrophoresis of genomic DNA to show that Top3, unassisted by Sgs1 and Rmi1, has modest capacities to provide resistance to MMS and to resolve recombination-dependent X-shaped molecules. The X-shaped molecules have structural properties consistent with hemicatenane-related template switch recombination intermediates (Rec-Xs) but not Holliday …

Notchless Interacts With Multiple Signaling Pathways During Mouse Peri-Implantation Development, Chiao-Ling Lo

Open Access Dissertations

During peri-implantation, the embryo transitions from a suspension environment in the fallopian tubes to an adherent system within the uterus. Successful transition requires maternal and fetal signaling cascades that establish maternal-fetal boundaries. Failure is common, as ~ 25% of all human pregnancies terminate during these steps. A large-scale mutation study in mice produced two mutants (l11Jus1 and l11Jus4) that are excellent models of this transition. l11Jus1 and l11Jus4 contain missense mutations in the Notchless homolog 1 (Drosophila) (Nle1) gene. NLE1 is thought to signal via the canonical NOTCH pathway in vertebrates. Although in invertebrates and lower vertebrates, NOTCH signaling directs …

Natural Genetic Variation Affecting Calcium Homeostasis, Rebecca Anna Replogle

Open Access Dissertations

Calcium (Ca) is essential for multiple functions within the body including skeletal health. The level of Ca in the serum is tightly regulated. During periods of habitual low Ca intake, the body senses a decrease in serum Ca and increases renal conversion of 25 hydroxyvitamin D (25(OH)D) to 1,25 dihydroxyvitamin D (1,25(OH)2D). 1,25(OH)2D acts through the vitamin D receptor (VDR) to increase intestinal Ca absorption, renal Ca reabsorption and skeletal Ca resorption. Efficient intestinal Ca absorption, especially during periods of low Ca intake, is critical for protecting bone mass. Ca absorption and its primary regulator, 1,25(OH)2D, are affected by both …

The Genetic Architecture Of Juvenile Migration In Rainbow Trout (Oncorhynchus Mykiss), Benjamin Charles Hecht

Open Access Dissertations

Animal migrations play a critical role in the health and balance of ecological systems and in the evolution and diversification of species, and this is perhaps best displayed amongst salmonid fishes (salmon, trout, and char) who exhibit variation in the propensity to migrate both within and among species. Rainbow and steelhead trout (Oncorhynchus mykiss), members of the salmonid family of fishes, capture this variation throughout their native range. Some populations and ecotypes will remain resident in freshwater habitats throughout their life history; while others have the ability to embark on tremendous marine migrations. Those that migrate undergo a suite of …

Identifying Chromosome Rearrangements In The Allopolyploid Brassica Napus Using Pyrosequencing, Alexandra R. Barbella

Master's Theses

Allopolyploids form through the hybridization of two or more diploid genomes. A challenge to reproduction in allopolyploids is that pairing can occur between homologous chromosomes or homeologous chromosomes (i.e.different subgenomes.). Crossover between homeologous chromosomes can result in chromosome rearrangements that lower fertility and overall fitness. Rearrangements can alter the dosage of either entire chromosomes or just parts of chromosomes. Understanding the frequency and extent of rearrangements will help to explain the evolution and genome stabilization of agriculturally important allopolyploid species. Pyrosequencing is a useful tool in the study dosage changes in allopolyploids because it allows quantification of the relative contribution …

Gene Expression Life History Markers In A Hatchery And A Wild Population Of Young-Of-The-Year Oncorhynchus Mykiss, Ian D. F. Garrett

Dissertations and Theses

Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life histories within a single species has been researched extensively. In salmonid fishes, more than almost any other group, varying environmental conditions give rise to individuals within species that take markedly different life history trajectories.

Oncorhynchus mykissis a species of salmonid native to the Pacific Northwest region of North America. This species has two life history forms, anadromous and resident. The anadromous form spends a portion of its life in ocean while the resident life …

Function Of A Novel Checkpoint Protein In The Germ Line, Steven Drellishak, Marina Bykova, G. Valentin Börner

Undergraduate Research Posters 2013

Successful reproduction of Saccharomyces cerevisiae relies on the organism’s ability to complete the meiotic cell cycle and produce viable gametes. Zip1 is a protein that constitutes the central component of a protein structure that connects homologous chromosomes known as the synaptonemal complex. Zip1 is important for progression through the meiotic cell cycle. The C terminus of the coiled-coil Zip 1 protein is responsible for localization to the axes of the chromosomes. An internal deletion near the C terminus of Zip1, called zip1-c1, yields a stronger meiotic arrest than a mutation where Zip1 is completely deleted. The more efficient meiotic progression …

Maternal Genital Tract Colonisation By Group-B Streptococcus: A Hospital Based Study, Nida Najmi, Rozina Sikandar, Nadeem F. Zuberi, Imtiaz Jehan

Department of Obstetrics & Gynaecology

Objectives: To determine the prevalence of Group B Streptococcus genital tract infection in pregnant women and to determine the risk factors for its colonisation.
Methods: The cross-sectional study was conducted at the Aga Khan University Hospital, Karachi and Sobhraj Hospital, Karachi, from May to August 2007. Pregnant women at 35-37 weeks gestation attending antenatal clinic at these hospitals constituted the study population. Based on stratified sampling, 405 patients were recruited. High vaginal swabs of these patients were taken in order to calculate the prevalence of infection at each hospital. Logistic regression was used to evaluate the risk factor association. SPSS …

Identifying Molecular Markers Associated With Salt And Boron Tolerance In Poplar Trees, Darshanpreet Gill, Nathan Follen, Davis W. Cheng, Kyan Salehi, Gary Banuelos, James P. Prince

STAR Program Research Presentations

Standard irrigation practices promote salt and boron accumulation in soils on the Westside of Central California. The build-up of these inorganic salts leads to the degradation of arable land and reduction of crop production. Different clones of poplar trees have been shown to grow in salt- and boron-contaminated soils, and in doing so, gradually remove significant amounts of these inorganic salts from the soil. In an effort to identify molecular markers linked with salt and boron tolerance in poplars, 31 PCR primer pairs have been designed based on candidate genes identified from the literature, and an additional 31 PCR primer …

Creating A Package In R, Brit Schneiders, Eric Archer

STAR Program Research Presentations

In a time of increasingly efficient technology and data production, scientists are producing data faster than it can be analyzed. Therefore, user accessibility to data analysis is becoming more and more critical. In general, researchers have a set of raw data and want an efficient means to their final analysis. A package serves as that means by creating a set of functions and making them accessible to the user. Often, a user has a small piece of code to run (a single R script, for example), and that script requires the use of certain functions, which are contained in a …

Development Of Tools To Assess The Effects Of Lunasin On Normal Development And Tumor Progression In Drosophila Melanogaster, Gillian E. Jones

Masters Theses & Specialist Projects

Soy contains many bioactive molecules known to elicit anti-cancer effects. One such peptide, Lunasin, has been shown to selectively act on newly transformed cells while having no cytotoxic effect on non-tumorigenic or established cancer cell lines. In this study we attempt to understand the developmental effects of Lunasin overexpression in vivo and create reagents that will help us understand Lunasin’s anti tumorigenic effects in an intact organism. cDNA encoding lunasin and EGFP-lunasin were cloned into pUAST and microinjected into Drosophila embryos. Tissue-specific overexpression of EGFP-Lun in the resulting transgenic lines was accomplished by crossing transgenics to various GAL4 driver lines. …

Recurrent Modification Of A Conserved Cis-Regulatory Element Underlies Fruit Fly Pigmentation Diversity, William A. Rogers, Joseph R. Salomone, David J. Tacy, Eric M. Camino, Kristen A. Davis, Mark Rebeiz, Thomas M. Williams

Biology Faculty Publications

The development of morphological traits occurs through the collective action of networks of genes connected at the level of gene expression. As any node in a network may be a target of evolutionary change, the recurrent targeting of the same node would indicate that the path of evolution is biased for the relevant trait and network. Although examples of parallel evolution have implicated recurrent modification of the same gene and cis-regulatory element (CRE), little is known about the mutational and molecular paths of parallel CRE evolution. InDrosophila melanogaster fruit flies, the Bric-à-brac (Bab) transcription factors control the development …

Prkca: Identification Of A Novel Downstream Target Of Wt1, Devin Jones

Dissertations and Theses (Open Access)

Wilms tumor is a childhood tumor of the kidney arising from the undifferentiated metanephric mesenchyme. Tumorigenesis is attributed to a number of genetic and epigenetic alterations. In 20% of Wilms tumors, Wilms tumor gene 1 (WT1) undergoes inactivating homozygous mutations causing loss of function of the zinc finger transcription factor it encodes. It is hypothesized that mutations in WT1 result in dysregulation of downstream target genes, leading to aberrant kidney development and/or Wilms tumor. These downstream target genes are largely unknown, and identification is important for further understanding Wilms tumor development. Heatmap data of human Wilms tumor protein …

Relationship Of Global Dna Methylation With Cardiovascular Fitness And Body Composition, Michael Steele Jarrett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: Global DNA Methylation (GDM), an epigenomic modification has been linked to the development of Cardiovascular Disease and its risk factors. Purpose: The purpose of this study was to determine if there is a significant correlation between GDM and cardiovascular fitness, as well as, measures of body composition. Methodology: 26 apparently healthy, adults (11 males) completed a physical activity and diet questionnaire, as well as, had a small blood sample (600μL) collected via finger prick for the determination of GDM. Body composition was assessed by means of a Dual-Energy X-ray Absorptiometry (DEXA) scan, while cardiovascular fitness was evaluated by the …

Reactin: Regulatory Activity Inference Of Transcription Factors Underlying Human Diseases With Application To Breast Cancer, Mingzhu Zhu, Chun-Chi Liu, Chao Cheng

Dartmouth Scholarship

Genetic alterations of transcription factors (TFs) have been implicated in the tumorigenesis of cancers. In many cancers, alteration of TFs results in aberrant activity of them without changing their gene expression level. Gene expression data from microarray or RNA-seq experiments can capture the expression change of genes, however, it is still challenge to reveal the activity change of TFs. Here we propose a method, called REACTIN (REgulatory ACTivity INference), which integrates TF binding data with gene expression data to identify TFs with significantly differential activity between disease and normal samples. REACTIN successfully detect differential activity of estrogen receptor (ER) between …

Differential Regulation Of White-Opaque Switching By Individual Subunits Of Candida Albicans Mediator, Anda Zhang, Zhongle Liu, Lawrence C. Myers

Dartmouth Scholarship

The multisubunit eukaryotic Mediator complex integrates diverse positive and negative gene regulatory signals and transmits them to the core transcription machinery. Mutations in individual subunits within the complex can lead to decreased or increased transcription of certain subsets of genes, which are highly specific to the mutated subunit. Recent studies suggest a role for Mediator in epigenetic silencing. Using white-opaque morphological switching in Candida albicans as a model, we have shown that Mediator is required for the stability of both the epigenetic silenced (white) and active (opaque) states of the bistable transcription circuit driven by the master regulator Wor1. Individual …

The Rate And Effects Of Spontaneous Mutation On Fitness Traits In The Social Amoeba, Dictyostelium Discoideum, David W. Hall, Sara Fox, Jennie J. Kuzdzal-Fick, Joan E. Strassmann, David C. Queller

Biology Faculty Research

We performed a mutation accumulation (MA) experiment in the social amoeba Dictyostelium discoideum to estimate the rate and distribution of effects of spontaneous mutations affecting eight putative fitness traits. We found that the per-generation mutation rate for most fitness components is 0.0019 mutations per haploid genome per generation or larger. This rate is an order of magnitude higher than estimates for fitness components in the unicellular eukaryote Saccharomyces cerevisiae, even though the base-pair substitution rate is two orders of magnitude lower. The high rate of fitness-altering mutations observed in this species may be partially explained by a large mutational target …

A Comprehensive And Integrative Reconstruction Of Evolutionary History For Anomura (Crustacea: Decapoda)., Heather D Bracken-Grissom, Maren E Cannon, Patricia Cabezas, Rodney M Feldmann, Carrie E Schweitzer, Shane T Ahyong, Darryl L Felder, Rafael Lemaitre, Keith A Crandall

Computational Biology Institute

BACKGROUND: The infraorder Anomura has long captivated the attention of evolutionary biologists due to its impressive morphological diversity and ecological adaptations. To date, 2500 extant species have been described but phylogenetic relationships at high taxonomic levels remain unresolved. Here, we reconstruct the evolutionary history-phylogeny, divergence times, character evolution and diversification-of this speciose clade. For this purpose, we sequenced two mitochondrial (16S and 12S) and three nuclear (H3, 18S and 28S) markers for 19 of the 20 extant families, using traditional Sanger and next-generation 454 sequencing methods. Molecular data were combined with 156 morphological characters in order to estimate the largest …

Evolution Of A Higher Intracellular Oxidizing Environment In Caenorhabditis Elegans Under Relaxed Selection, Joanna Joyner-Matos, Kiley A. Hicks, Dustin Cousins, Michelle Keller, Dee R. Denver, Charles F. Baer, Suzanne Estes

Biology Faculty Publications and Presentations

We explored the relationship between relaxed selection, oxidative stress, and spontaneous mutation in a set of mutationaccumulation (MA) lines of the nematode Caenorhabditis elegans and in their common ancestor. We measured steady-state levels of free radicals and oxidatively damaged guanosine nucleosides in the somatic tissues of five MA lines for which nuclear genome base substitution and GC-TA transversion frequencies are known. The two markers of oxidative stress are highly correlated and are elevated in the MA lines relative to the ancestor; point estimates of the per-generation rate of mutational decay (DM) of these measures of oxidative stress are similar to …

Science Fiction And The Myth Of Trajectory Evolution, Jocelyn D. Pickreign

The Macalester Review

Stephen Jay Gould first proposed the idea of “iconographies of progress.” Today, one of the most prominent forms of progress iconography is the science fiction story. Science fiction as a genre frequently portrays evolution as a linear trajectory of increasing complexity, and in doing so, furthers a worldview that is not unlike the pre-Darwin understanding of human beings as both the center and the pinnacle of the natural world.