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Genomics

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Articles 241 - 270 of 290

Full-Text Articles in Genetics and Genomics

Semantics In Support Of Biodiversity Knowledge Discovery: An Introduction To The Biological Collections Ontology And Related Ontologies, Ramona L. Walls, John Deck, Robert Guralnick, Steve Baskauf, Reed Beaman, Stanley Blum, Shaun Bowers Jan 2014

Semantics In Support Of Biodiversity Knowledge Discovery: An Introduction To The Biological Collections Ontology And Related Ontologies, Ramona L. Walls, John Deck, Robert Guralnick, Steve Baskauf, Reed Beaman, Stanley Blum, Shaun Bowers

Computer Science Faculty Scholarship

The study of biodiversity spans many disciplines and includes data pertaining to species distributions and abundances, genetic sequences, trait measurements, and ecological niches, complemented by information on collection and measurement protocols. A review of the current landscape of metadata standards and ontologies in biodiversity science suggests that existing standards such as the Darwin Core terminology are inadequate for describing biodiversity data in a semantically meaningful and computationally useful way. Existing ontologies, such as the Gene Ontology and others in the Open Biological and Biomedical Ontologies (OBO) Foundry library, provide a semantic structure but lack many of the necessary terms to …


Small Rna Expression During Programmed Rearragement Of A Vertebrate Genome, Joseph R. Herdy Iii Jan 2014

Small Rna Expression During Programmed Rearragement Of A Vertebrate Genome, Joseph R. Herdy Iii

Theses and Dissertations--Biology

The sea lamprey (Petromyzon marinus) undergoes programmed genome rearrangements (PGRs) during embryogenesis that results in the deletion of ~0.5 Gb of germline DNA from the somatic lineage. The underlying mechanism of these rearrangements remains largely unknown. miRNAs (microRNAs) and piRNAs (PIWI interacting RNAs) are two classes of small noncoding RNAs that play important roles in early vertebrate development, including differentiation of cell lineages, modulation of signaling pathways, and clearing of maternal transcripts. Here, I utilized next generation sequencing to determine the temporal expression of miRNAs, piRNAs, and other small noncoding RNAs during the first five days of lamprey …


Methods For Integrative Analysis Of Genomic Data, Paul Manser Jan 2014

Methods For Integrative Analysis Of Genomic Data, Paul Manser

Theses and Dissertations

In recent years, the development of new genomic technologies has allowed for the investigation of many regulatory epigenetic marks besides expression levels, on a genome-wide scale. As the price for these technologies continues to decrease, study sizes will not only increase, but several different assays are beginning to be used for the same samples. It is therefore desirable to develop statistical methods to integrate multiple data types that can handle the increased computational burden of incorporating large data sets. Furthermore, it is important to develop sound quality control and normalization methods as technical errors can compound when integrating multiple genomic …


A Systems Biology Approach To Detect Eqtls Associated With Mirna And Mrna Co-Expression Networks In The Nucleus Accumbens Of Chronic Alcoholic Patients, Mohammed Mamdani Jan 2014

A Systems Biology Approach To Detect Eqtls Associated With Mirna And Mrna Co-Expression Networks In The Nucleus Accumbens Of Chronic Alcoholic Patients, Mohammed Mamdani

Theses and Dissertations

Alcohol Dependence (AD) is a chronic substance use disorder with moderate heritability (60%). Linkage and genome-wide association studies (GWAS) have implicated a number of loci; however, the molecular mechanisms underlying AD are unclear. Advances in systems biology allow genome-wide expression data to be integrated with genetic data to detect expression quantitative trait loci (eQTL), polymorphisms that regulate gene expression levels, influence phenotypes and are significantly enriched among validated genetic signals for many commonly studied traits including AD.

We integrated genome-wide mRNA and miRNA expression data with genotypic data from the nucleus accumbens (NAc), a major addiction-related brain region, of 36 …


Redefining Genomic Privacy: Trust And Empowerment, Yaniv Erlich, James B. Williams, David Glazer, Kenneth Yocum, Nita A. Farahany, Maynard Olson, Arvind Narayanan, Lincoln D. Stein, Jan A. Witkowski, Robert C. Kain Jan 2014

Redefining Genomic Privacy: Trust And Empowerment, Yaniv Erlich, James B. Williams, David Glazer, Kenneth Yocum, Nita A. Farahany, Maynard Olson, Arvind Narayanan, Lincoln D. Stein, Jan A. Witkowski, Robert C. Kain

Faculty Scholarship

Fulfilling the promise of the genetic revolution requires the analysis of large datasets containing information from thousands to millions of participants. However, sharing human genomic data requires protecting subjects from potential harm. Current models rely on de-identification techniques in which privacy versus data utility becomes a zero-sum game. Instead, we propose the use of trust-enabling techniques to create a solution in which researchers and participants both win. To do so we introduce three principles that facilitate trust in genetic research and outline one possible framework built upon those principles. Our hope is that such trust-centric frameworks provide a sustainable solution …


Integrating Human Omics Data To Prioritize Candidate Genes., Yong Chen, Xuebing Wu, Rui Jiang Dec 2013

Integrating Human Omics Data To Prioritize Candidate Genes., Yong Chen, Xuebing Wu, Rui Jiang

College of Science & Mathematics Departmental Research

BACKGROUND: The identification of genes involved in human complex diseases remains a great challenge in computational systems biology. Although methods have been developed to use disease phenotypic similarities with a protein-protein interaction network for the prioritization of candidate genes, other valuable omics data sources have been largely overlooked in these methods.

METHODS: With this understanding, we proposed a method called BRIDGE to prioritize candidate genes by integrating disease phenotypic similarities with such omics data as protein-protein interactions, gene sequence similarities, gene expression patterns, gene ontology annotations, and gene pathway memberships. BRIDGE utilizes a multiple regression model with lasso penalty to …


On The Origin Of Phenotypic Variation: Novel Technologies To Dissect Molecular Determinants Of Phenotype, Francesco Vallania Dec 2013

On The Origin Of Phenotypic Variation: Novel Technologies To Dissect Molecular Determinants Of Phenotype, Francesco Vallania

All Theses and Dissertations (ETDs)

This thesis describes the conception, design, and development of novel computational tools, theoretical models, and experimental techniques applied to the dissection of molecular factors underlying phenotypic variation. The first part of my work is focused on finding rare genetic variants in pooled DNA samples, leading to the development of a novel set of algorithms, SNPseeker and SPLINTER, applied to next-generation sequencing data. The second part of my work describes the creation of a reporter system for DNA methylation for the purpose of dissecting the genetic contribution of tissue-specific patterns of DNA methylation across the genome. Finally the last part of …


Pathoscope: Species Identification And Strain Attribution With Unassembled Sequencing Data., Owen E Francis, Matthew Bendall, Solaiappan Manimaran, Changjin Hong, Nathan L Clement, Eduardo Castro-Nallar, Quinn Snell, G Bruce Schaalje, Mark J Clement, Keith A Crandall, W Evan Johnson Oct 2013

Pathoscope: Species Identification And Strain Attribution With Unassembled Sequencing Data., Owen E Francis, Matthew Bendall, Solaiappan Manimaran, Changjin Hong, Nathan L Clement, Eduardo Castro-Nallar, Quinn Snell, G Bruce Schaalje, Mark J Clement, Keith A Crandall, W Evan Johnson

Computational Biology Institute

Emerging next-generation sequencing technologies have revolutionized the collection of genomic data for applications in bioforensics, biosurveillance, and for use in clinical settings. However, to make the most of these new data, new methodology needs to be developed that can accommodate large volumes of genetic data in a computationally efficient manner. We present a statistical framework to analyze raw next-generation sequence reads from purified or mixed environmental or targeted infected tissue samples for rapid species identification and strain attribution against a robust database of known biological agents. Our method, Pathoscope, capitalizes on a Bayesian statistical framework that accommodates information on sequence …


Phage Cluster Relationships Identified Through Single Gene Analysis., Kyle C Smith, Eduardo Castro-Nallar, Joshua Nb Fisher, Donald P Breakwell, Julianne H Grose, Sandra H Burnett Jun 2013

Phage Cluster Relationships Identified Through Single Gene Analysis., Kyle C Smith, Eduardo Castro-Nallar, Joshua Nb Fisher, Donald P Breakwell, Julianne H Grose, Sandra H Burnett

Computational Biology Institute

BACKGROUND: Phylogenetic comparison of bacteriophages requires whole genome approaches such as dotplot analysis, genome pairwise maps, and gene content analysis. Currently mycobacteriophages, a highly studied phage group, are categorized into related clusters based on the comparative analysis of whole genome sequences. With the recent explosion of phage isolation, a simple method for phage cluster prediction would facilitate analysis of crude or complex samples without whole genome isolation and sequencing. The hypothesis of this study was that mycobacteriophage-cluster prediction is possible using comparison of a single, ubiquitous, semi-conserved gene. Tape Measure Protein (TMP) was selected to test the hypothesis because it …


Engaging Students In A Bioinformatics Activity To Introduce Gene Structure And Function, Barbara J. May May 2013

Engaging Students In A Bioinformatics Activity To Introduce Gene Structure And Function, Barbara J. May

Biology Faculty Publications

Bioinformatics spans many fields of biological research and plays a vital role in mining and analyzing data. Therefore, there is an ever-increasing need for students to understand not only what can be learned from this data, but also how to use basic bioinformatics tools. This activity is designed to provide secondary and undergraduate biology students to a hands-on activity meant to explore and understand gene structure with the use of basic bioinformatic tools. Students are provided an “unknown” sequence from which they are asked to use a free online gene finder program to identify the gene. Students then predict the …


Tracing Evolutionary Footprints To Identify Novel Gene Functional Linkages., Yong Chen, Li Yang, Yunfeng Ding, Shuyan Zhang, Tong He, Fenglou Mao, Congyan Zhang, Huina Zhang, Chaoxing Huo, Pingsheng Liu Jan 2013

Tracing Evolutionary Footprints To Identify Novel Gene Functional Linkages., Yong Chen, Li Yang, Yunfeng Ding, Shuyan Zhang, Tong He, Fenglou Mao, Congyan Zhang, Huina Zhang, Chaoxing Huo, Pingsheng Liu

College of Science & Mathematics Departmental Research

Systematic determination of gene function is an essential step in fully understanding the precise contribution of each gene for the proper execution of molecular functions in the cell. Gene functional linkage is defined as to describe the relationship of a group of genes with similar functions. With thousands of genomes sequenced, there arises a great opportunity to utilize gene evolutionary information to identify gene functional linkages. To this end, we established a computational method (called TRACE) to trace gene footprints through a gene functional network constructed from 341 prokaryotic genomes. TRACE performance was validated and successfully tested to predict enzyme …


Family Cancer History And Pedigrees As A Public Health Intervention For Promoting Health And Preventing Prostate Cancer In African American Men, Holisa Wharton Dec 2012

Family Cancer History And Pedigrees As A Public Health Intervention For Promoting Health And Preventing Prostate Cancer In African American Men, Holisa Wharton

All Dissertations

ABSTRACT
Prostate cancer is the most common cancer diagnosed in men and the second leading cause of cancer death among men in the United States. African-American men have substantially higher prostate cancer incidence and mortality than European-American men. It is unclear whether this incidence is due to acquired DNA changes (sporadic cancer) or if germline Mendelian genetics/genomics (inherited cancer) is the source of this health disparity. To explore this cause, the focus of this dissertation paper is family health history and hereditary prostate cancer. A family history tool is the most commonly used predictive instrument for hereditary prostate cancer. The …


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 …


Genomics Of Mature And Immature Olfactory Sensory Neurons, Melissa D. Nickell, Patrick Breheny, Arnold J. Stromberg, Timothy S. Mcclintock Aug 2012

Genomics Of Mature And Immature Olfactory Sensory Neurons, Melissa D. Nickell, Patrick Breheny, Arnold J. Stromberg, Timothy S. Mcclintock

Physiology Faculty Publications

The continuous replacement of neurons in the olfactory epithelium provides an advantageous model for investigating neuronal differentiation and maturation. By calculating the relative enrichment of every mRNA detected in samples of mature mouse olfactory sensory neurons (OSNs), immature OSNs, and the residual population of neighboring cell types, and then comparing these ratios against the known expression patterns of >300 genes, enrichment criteria that accurately predicted the OSN expression patterns of nearly all genes were determined. We identified 847 immature OSN-specific and 691 mature OSN-specific genes. The control of gene expression by chromatin modification and transcription factors, and neurite growth, protein …


Antisense Transcription Is Pervasive But Rarely Conserved In Enteric Bacteria, Rahul Raghavan, D. B. Sloan, H. Ochman Aug 2012

Antisense Transcription Is Pervasive But Rarely Conserved In Enteric Bacteria, Rahul Raghavan, D. B. Sloan, H. Ochman

Biology Faculty Publications and Presentations

Noncoding RNAs, including antisense RNAs (asRNAs) that originate from the complementary strand of protein-coding genes, are involved in the regulation of gene expression in all domains of life. Recent application of deep-sequencing technologies has revealed that the transcription of asRNAs occurs genome-wide in bacteria. Although the role of the vast majority of asRNAs remains unknown, it is often assumed that their presence implies important regulatory functions, similar to those of other noncoding RNAs. Alternatively, many antisense transcripts may be produced by chance transcription events from promoter-like sequences that result from the degenerate nature of bacterial transcription factor binding sites. To …


Condensin Ii Promotes The Formation Of Chromosome Territories By Inducing Axial Compaction Of Polyploid Interphase Chromosomes, Christopher R. R. Bauer, Tom A. Hartl, Giovanni Bosco Aug 2012

Condensin Ii Promotes The Formation Of Chromosome Territories By Inducing Axial Compaction Of Polyploid Interphase Chromosomes, Christopher R. R. Bauer, Tom A. Hartl, Giovanni Bosco

Dartmouth Scholarship

The eukaryotic nucleus is both spatially and functionally partitioned. This organization contributes to the maintenance, expression, and transmission of genetic information. Though our ability to probe the physical structure of the genome within the nucleus has improved substantially in recent years, relatively little is known about the factors that regulate its organization or the mechanisms through which specific organizational states are achieved. Here, we show that Drosophila melanogaster Condensin II induces axial compaction of interphase chromosomes, globally disrupts interchromosomal interactions, and promotes the dispersal of peri-centric heterochromatin. These Condensin II activities compartmentalize the nucleus into discrete chromosome territories and indicate …


Technical Desiderata For The Integration Of Genomic Data Into Electronic Health Records., Daniel R Masys, Gail P Jarvik, Neil F Abernethy, Nicholas R Anderson, George J Papanicolaou, Dina N Paltoo, Mark A Hoffman, Isaac S Kohane, Howard P Levy Jun 2012

Technical Desiderata For The Integration Of Genomic Data Into Electronic Health Records., Daniel R Masys, Gail P Jarvik, Neil F Abernethy, Nicholas R Anderson, George J Papanicolaou, Dina N Paltoo, Mark A Hoffman, Isaac S Kohane, Howard P Levy

Manuscripts, Articles, Book Chapters and Other Papers

The era of "Personalized Medicine," guided by individual molecular variation in DNA, RNA, expressed proteins and other forms of high volume molecular data brings new requirements and challenges to the design and implementation of Electronic Health Records (EHRs). In this article we describe the characteristics of biomolecular data that differentiate it from other classes of data commonly found in EHRs, enumerate a set of technical desiderata for its management in healthcare settings, and offer a candidate technical approach to its compact and efficient representation in operational systems.


Tissue Sampling Methods And Standards For Vertebrate Genomics, Pamela B. Y. Wong, Edward O. Wiley, Warren E. Johnson, Oliver A. Ryder, Stephen J. O'Brien, David Haussler, Klaus-Peter Koepfli, Marlys L. Houck, Polina L. Perelman, Gabriela Mastromonaco, Andrew C. Bentley, Byrappa Venkatesh, Ya-Ping Zhang, Robert W. Murphy, Genome 10k Project Community Of Scientists Jan 2012

Tissue Sampling Methods And Standards For Vertebrate Genomics, Pamela B. Y. Wong, Edward O. Wiley, Warren E. Johnson, Oliver A. Ryder, Stephen J. O'Brien, David Haussler, Klaus-Peter Koepfli, Marlys L. Houck, Polina L. Perelman, Gabriela Mastromonaco, Andrew C. Bentley, Byrappa Venkatesh, Ya-Ping Zhang, Robert W. Murphy, Genome 10k Project Community Of Scientists

Biology Faculty Articles

The recent rise in speed and efficiency of new sequencing technologies have facilitated high-throughput sequencing, assembly and analyses of genomes, advancing ongoing efforts to analyze genetic sequences across major vertebrate groups. Standardized procedures in acquiring high quality DNA and RNA and establishing cell lines from target species will facilitate these initiatives. We provide a legal and methodological guide according to four standards of acquiring and storing tissue for the Genome 10K Project and similar initiatives as follows: four-star (banked tissue/cell cultures, RNA from multiple types of tissue for transcriptomes, and sufficient flash-frozen tissue for 1 mg of DNA, all from …


Genome Empowerment For The Puerto Rican Parrot – Amazona Vittata, Stephen J. O'Brien Jan 2012

Genome Empowerment For The Puerto Rican Parrot – Amazona Vittata, Stephen J. O'Brien

Biology Faculty Articles

A unique community-funded project in Puerto Rico has launched whole-genome sequencing of the critically endangered Puerto Rican Parrot (Amazona vittata), with interpretation by genome bioinformaticians and students, and deposition into public online databases. This is the first article that focuses on the whole genome of a parrot species, one endemic to the USA and recently threatened with extinction. It provides invaluable conservation tools and a vivid example of hopeful prospects for future genome assessment of so many new species. It also demonstrates inventive ways for smaller institutions to contribute to a field largely considered the domain of large …


Large-Scale Rnai Screen Of G Protein-Coupled Receptors Involved In Larval Growth, Molting And Metamorphosis In The Red Flour Beetle, Hua Bai, Fang Zhu, Kapil Shah, Subba R. Palli Aug 2011

Large-Scale Rnai Screen Of G Protein-Coupled Receptors Involved In Larval Growth, Molting And Metamorphosis In The Red Flour Beetle, Hua Bai, Fang Zhu, Kapil Shah, Subba R. Palli

Entomology Faculty Publications

BACKGROUND: The G protein-coupled receptors (GPCRs) belong to the largest superfamily of integral cell membrane proteins and play crucial roles in physiological processes including behavior, development and reproduction. Because of their broad and diverse roles in cellular signaling, GPCRs are the therapeutic targets for many prescription drugs. However, there is no commercial pesticide targeting insect GPCRs. In this study, we employed functional genomics methods and used the red flour beetle, Tribolium castaneum, as a model system to study the physiological roles of GPCRs during the larval growth, molting and metamorphosis.

RESULTS: A total of 111 non-sensory GPCRs were identified in …


Synthetic Hype: A Skeptical View Of The Promise Of Synthetic Biology, Jonathan Kahn Jan 2011

Synthetic Hype: A Skeptical View Of The Promise Of Synthetic Biology, Jonathan Kahn

Faculty Scholarship

This article urges a cautious approach to assessing the promises of synthetic biology based on broad political and economic concerns rather than technical ones. Specifically, I mark three related dynamics which place the current buzz around synthetic biology in a broader context. These dynamics are not necessarily distinctive to synthetic biology, but perhaps for that very reason, they may carry added weight. First, is the place of synthetic biology as the latest entry in the procession of what I call the “receding horizons of biotechnological promise.” Second, is the excitement generated by the related promise of finding seemingly direct technological …


Integrating Evolutionary And Functional Approaches To Infer Adaptation At Specific Loci, Jay F. Storz, Christopher W. Wheat Sep 2010

Integrating Evolutionary And Functional Approaches To Infer Adaptation At Specific Loci, Jay F. Storz, Christopher W. Wheat

Jay F. Storz Publications

Inferences about adaptation at specific loci are often exclusively based on the static analysis of DNA sequence variation. Ideally, population-genetic evidence for positive selection serves as a stepping-off point for experimental studies to elucidate the functional significance of the putatively adaptive variation. We argue that inferences about adaptation at specific loci are best achieved by integrating the indirect, retrospective insights provided by population-genetic analyses with the more direct, mechanistic insights provided by functional experiments. Integrative studies of adaptive genetic variation may sometimes be motivated by experimental insights into molecular function, which then provide the impetus to perform population genetic tests …


Density Based Pruning For Identification Of Differentially Expressed Genes From Microarray Data, Jianjun Hu, J. Xu Jan 2010

Density Based Pruning For Identification Of Differentially Expressed Genes From Microarray Data, Jianjun Hu, J. Xu

Faculty Publications

Motivation

Identification of differentially expressed genes from microarray datasets is one of the most important analyses for microarray data mining. Popular algorithms such as statistical t-test rank genes based on a single statistics. The false positive rate of these methods can be improved by considering other features of differentially expressed genes.

Results

We proposed a pattern recognition strategy for identifying differentially expressed genes. Genes are mapped to a two dimension feature space composed of average difference of gene expression and average expression levels. A density based pruning algorithm (DB Pruning) is developed to screen out potential differentially expressed genes usually …


Using Jackknife To Assess The Quality Of Gene Order Phylogenies, Jian Shi, Yiwei Zhang, Haiwei Luo, Jijun Tang Jan 2010

Using Jackknife To Assess The Quality Of Gene Order Phylogenies, Jian Shi, Yiwei Zhang, Haiwei Luo, Jijun Tang

Faculty Publications

Background
In recent years, gene order data has attracted increasing attention from both biologists and computer scientists as a new type of data for phylogenetic analysis. If gene orders are viewed as one character with a large number of states, traditional bootstrap procedures cannot be applied. Researchers began to use a jackknife resampling method to assess the quality of gene order phylogenies.

Results
In this paper, we design and conduct a set of experiments to validate the performance of this jackknife procedure and provide discussions on how to conduct it properly. Our results show that jackknife is very useful to …


Genome3d: A Viewer-Model Framework For Integrating And Visualizing Multi-Scale Epigenomic Information Within A Three-Dimensional Genome, Thomas M. Asbury, Matt Mitman, Jijun Tang, W. Jim Zheng Jan 2010

Genome3d: A Viewer-Model Framework For Integrating And Visualizing Multi-Scale Epigenomic Information Within A Three-Dimensional Genome, Thomas M. Asbury, Matt Mitman, Jijun Tang, W. Jim Zheng

Faculty Publications

Background
New technologies are enabling the measurement of many types of genomic and epigenomic information at scales ranging from the atomic to nuclear. Much of this new data is increasingly structural in nature, and is often difficult to coordinate with other data sets. There is a legitimate need for integrating and visualizing these disparate data sets to reveal structural relationships not apparent when looking at these data in isolation.

Results
We have applied object-oriented technology to develop a downloadable visualization tool, Genome3D, for integrating and displaying epigenomic data within a prescribed three-dimensional physical model of the human genome. In order …


Cloning Of "Animal Cryptochrome" Cdna From The Model Organism Chlamydomonas Reinhardtii For Functional Analysis Of Its Protein Product, Shobha Lavanya Silparasetty Dec 2009

Cloning Of "Animal Cryptochrome" Cdna From The Model Organism Chlamydomonas Reinhardtii For Functional Analysis Of Its Protein Product, Shobha Lavanya Silparasetty

Masters Theses & Specialist Projects

reinhardtii, a unicellular green alga, is a model organism to study the circadian clock. Cryptochromes are the blue light photoreceptors that entrain the clock in some organisms. The CPH1 protein of C. reinhardtii resembles the cryptochromes of the plant model Arabidopsis, but whether CPH1 entrains the circadian clock in C. reinhardtii is not yet known. Recent reports have suggested the existence of one more cryptochrome in C. reinhardtii, which resembles the cryptochromes of animals. However, the amino acid sequence of this protein shows even higher sequence similarity with the 6-4 DNA photolyase of Arabidopsis. DNA photolyases …


Microbial Nad Metabolism: Lessons From Comparative Genomics, Francesca Gazzaniga, Rebecca Stebbins, Sheila Z. Chang, Mark A. Mcpeek, Charles Brenner Sep 2009

Microbial Nad Metabolism: Lessons From Comparative Genomics, Francesca Gazzaniga, Rebecca Stebbins, Sheila Z. Chang, Mark A. Mcpeek, Charles Brenner

Dartmouth Scholarship

NAD is a coenzyme for redox reactions and a substrate of NAD-consuming enzymes, including ADP-ribose transferases, Sir2-related protein lysine deacetylases, and bacterial DNA ligases. Microorganisms that synthesize NAD from as few as one to as many as five of the six identified biosynthetic precursors have been identified. De novo NAD synthesis from aspartate or tryptophan is neither universal nor strictly aerobic. Salvage NAD synthesis from nicotinamide, nicotinic acid, nicotinamide riboside, and nicotinic acid riboside occurs via modules of different genes. Nicotinamide salvage genes nadV and pncA, found in distinct bacteria, appear to have spread throughout the tree of life …


Bridging Functional Genomics And Toxicogenomics Through Dna Microarrays In A Fish Model, Shuzhao Li Aug 2009

Bridging Functional Genomics And Toxicogenomics Through Dna Microarrays In A Fish Model, Shuzhao Li

Dissertations

In a case study of finding gene expression signatures for environmental stressors in Cyprinodon variegatus, this dissertation examines several important issues of applying DNA microarray technology to fish toxicogenomics. The most relevant disciplines, fish toxicogenomics and computational systems biology are reviewed in Chapter 1. Chapter 2 reviews major aspects of DNA microarray technology.

On DNA microarrays, even for probes that target the same transcript, large variations are seen in the probe signals. These variations are partly dependent and partly independent on probe sequences. Chapter 3 estimates the sequence independent variation by combining experimental and computational approaches. Chapter 4 and …


Gene Order Phylogeny And The Evolution Of Methanogens, Haiwei Luo, Zhiyi Sun, William Arndt, Jian Shi, Robert Friedman, Jijun Tang Jun 2009

Gene Order Phylogeny And The Evolution Of Methanogens, Haiwei Luo, Zhiyi Sun, William Arndt, Jian Shi, Robert Friedman, Jijun Tang

Faculty Publications

Methanogens are a phylogenetically diverse group belonging to Euryarchaeota. Previously, phylogenetic approaches using large datasets revealed that methanogens can be grouped into two classes, “Class I” and “Class II”. However, some deep relationships were not resolved. For instance, the monophyly of “Class I” methanogens, which consist of Methanopyrales, Methanobacteriales and Methanococcales, is disputable due to weak statistical support. In this study, we use MSOAR to identify common orthologous genes from eight methanogen species and a Thermococcale species (outgroup), and apply GRAPPA and FastME to compute distance-based gene order phylogeny. The gene order phylogeny supports two classes of methanogens, but it …


Correcting The Site Frequency Spectrum For Divergence-Based Ascertainment, Andrew D. Kern Apr 2009

Correcting The Site Frequency Spectrum For Divergence-Based Ascertainment, Andrew D. Kern

Dartmouth Scholarship

Comparative genomics based on sequenced referenced genomes is essential to hypothesis generation and testing within population genetics. However, selection of candidate regions for further study on the basis of elevated or depressed divergence between species leads to a divergence-based ascertainment bias in the site frequency spectrum within selected candidate loci. Here, a method to correct this problem is developed that obtains maximum-likelihood estimates of the unascertained allele frequency distribution using numerical optimization. I show how divergence-based ascertainment may mimic the effects of natural selection and offer correction formulae for performing proper estimation into the strength of selection in candidate regions …