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The role of heritability in mapping expression quantitative trait loci

BMC proceedings 2007年第1期1 Suppl 1卷 S86页

作者： Song Huang David Ballard Hongyu Zhao Program of Computational Biology and Bioinformatics Yale University New Haven Connecticut 06520 USA. song.huang@yale.edu

Gene expression, as a heritable complex trait, has recently been used in many genome-wide linkage studies. The estimated overall heritability of each trait may be considered as evidence of a genetic contribution to the total phenotypic variation, which implies the possibility of mapping genome regions responsible for the gene expression variation via linkage analysis. However, heritability has been found to be an inconsistent predictor of significant linkage signals. To investigate this issue in human studies, we performed genome-wide linkage analysis on the 3554 gene expression traits of 194 Centre d'Etude du Polymorphisme Humain individuals provided by Genetic Analysis Workshop 15. Out of the 422 expression traits with significant linkage signals identified (LOD > 5.3), 89 traits have low estimated heritability (h2 < 10%), among which 23 traits have an estimated heritability equal to 0. The linkage analysis on individual pedigree shows that the overall LOD scores may result from a few pedigrees with strong linkage signals. Screening gene expressions before linkage analysis using a relatively low heritability (h2 < 20%) may result in a loss of significant linkage signals, especially for trans-acting expression quantitative trait loci (49%).

关键词： Linkage Analysis Heritability Estimate Expression Trait Genetic Analysis Workshop Select Gene Expression

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Modeling protein interaction network and mechanisms in exocytosis

Modeling protein interaction network and mechanisms in exocy...

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7th IEEE International Conference on bioinformatics and Bioengineering, BIBE

作者： Zhou, Wen Xia, Tian Tong, Jiansong Dickerson, Julie Su, Bo Gu, Xun Department of Mathematics Iowa State University Ames IA 50010 United States Program of Bioinformatics and Computational Biology Iowa State University Ames IA 50010 United States Department of Biochemistry Biophysics and Molecular Biology Iowa State University Ames IA 50010 United States Department of Genetics Development and Cell Biology Iowa State University Ames IA 50010 United States

ISBN: (纸本)1424415098

Exocytosis is an essential process in all eukaryotic cells that allows communication in cells through vesicles which contain a wide range of intracellular molecules such as hormones, matrix proteins and neurotransmitters. Recent studies have shown this process is regulated by molecular interactions among a group of well defined and conserved proteins. To gain insight into the dynamics of these interactions, we use protein interaction network modeling to investigate exocytotic system (particularly in endocrine) computationally and mathematically. The protein interactions are formulated into ordinary differential equations (ODE). We then apply a novel mathematic approach to estimate model parameters from experimental data for SNAREs-only network (with three key proteins), which is a subset of this system. Our approach is able to sense temporal changes in protein concentration and ratios of multiple proteins and precisely reconstruct the dynamical process of exocytosis, including vesicle docking, priming and fusion. Additionally, the model suggests that initial concentration of synaptic proteins plays a crucial role in efficiency of vesicle fusion, based on system stability analysis. ©2007 IEEE.

关键词： Proteins

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Hot and cold: Spatial fluctuation in HIV-1 recombination rates

Hot and cold: Spatial fluctuation in HIV-1 recombination rat...

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7th IEEE International Conference on bioinformatics and Bioengineering, BIBE

作者： Rajaram, M.L. Minin, V.N. Suchard, M.A. Dorman, K.S. Bioinformatics and Computational Biology Program Iowa State University Ames IA 50011 United States Department of Statistics University of Washington Seattle WA 98195 United States Departments of Biomathematics Human Genetics and Biostatistics University of California Los Angeles Los Angeles CA 90095 United States Departments of Statistics and Genetics Development and Cell Biology Iowa State University Ames IA 50011 United States

ISBN: (纸本)1424415098

Coinfection of a single cell with two or more HIV strains may produce recombinant viruses upon template switching by the replication machinery. We applied a hierarchical multiple change point model to simultaneously infer inter-subtype recombination breakpoints and spatial variation in the recombination rate along the HIV-1 genome. We examined thousands of publicly available HIV-1 sequences representing the worldwide epidemic and focused on 544 unique recombinants with 1, 701 recombination breakpoints. Estimates of per site recombination rate revealed the presence of a novel hotspot in the pol gene, surrounded by a cluster of mutations associated with resistance to reverse transcriptase inhibitors. We also confirm the presence of a known hotspot in the env gene and a previously hypothesized hotspot in the gag gene. ©2007 IEEE.

关键词： Genes

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PRTAD: A database for protein residue torsion angle distributions

PRTAD: A database for protein residue torsion angle distribu...

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IEEE International Conference on bioinformatics and Biomedicine Workshops (BIBMW)

作者： Xiaoyong Sun Di Wu Robert Jernigan Zhijun Wu Program on Bioinformatics and Computational Biology Department of Mathematics Western Kentucky University Bowling Green KY USA Department of Biochemistry Biophysics and Molecular Biology Department of Mathematics Iowa State University Ames IA USA

PRTAD is a dedicated database and structural bioinformatics system for protein analysis and modeling. The database is developed to host and analyze the statistical data for protein residue level "virtual" bond and torsion angles obtained from their distributions in databases of known protein structures such as in the PDB Data Bank. PRTAD is capable of generating, caching, and displaying the statistical distributions of the angles of various types. The collected information can be used to extract geometric restraints or define statistical potentials for protein structure determination. PRTAD is supported with a friendly designed web interface so that users can easily specify the angle types, and retrieve, visualize, or download the distributions of the angles as they desire. The database PRTAD is freely accessible at http://***/prtad.

关键词： Bonding Spatial databases Protein engineering Amino acids bioinformatics computational biology Mathematics Data mining Niobium compounds Nuclear magnetic resonance

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Comparison of experimental and computed protein anisotropic temperature factors

Comparison of experimental and computed protein anisotropic ...

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IEEE International Conference on bioinformatics and Biomedicine Workshops (BIBMW)

作者： Lei Yang Guang Song Robert L. Jernigan Program of Bioinformatics and Computational Biology Department of Biochemistry Biophysics and Molecular Biology Iowa State University Ames IA USA Department of Computer Science Iowa State University Ames IA USA Department of Biochemistry Biophysics and Molecular Biology L. H. Baker Center for Bioinformatics and Biological Statistics Iowa State University Ames IA USA

Because of its appealing simplicity, the anisotropic network model (ANM) has been widely accepted and applied to study many molecular motion problems: such as the molecular mechanisms of GroEL-GroES function, allosteric changes in hemoglobin, ribosome motion, motor-protein motions, and conformational changes in general, etc. However, the validity of the ANM has not been closely examined. In this work, we use ANM to predict the anisotropic temperature factors of proteins. On the flip side, the rich, directional anisotropic temperature factor data available for hundreds of proteins in the protein data bank (PDB) are used as validation data to closely test the ANM model. The significance of this work is that it presents a timely, important evaluation of the model, shows the extent of its accuracy in reproducing experimental anisotropic temperature factors, and suggests ways to improve the model. An improved model will help us better understand the internal dynamics of proteins, which in turn can greatly expand the usefulness of the models, which has already been demonstrated in many applications.

关键词： Proteins Anisotropic magnetoresistance Temperature Fluctuations computational biology biology computing Computer networks bioinformatics Biochemistry Biophysics

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Decision fusion of circulating markers for breast cancer detection in premenopausal women

Decision fusion of circulating markers for breast cancer det...

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7th IEEE International Conference on bioinformatics and Bioengineering, BIBE

作者： Jesneck, Jonathan L. Mukherjee, Sayan Nolte, Loren W. Lokshin, Anna E. Marks, Jeffrey R. Lo, Joseph Department of Biomedical Engineering Department of Statistical Science Computational Biology and Bioinformatics Program Duke Advanced Imaging Labs. Institute for Genome Sciences and Policy Department of Computer Science Duke University Department of Electrical and Computer Engineering Division of Hematology/Oncology University of Pittsburgh School of Medicine University of Pittsburgh Cancer Institute Pittsburgh PA 15213 United States Department of Experimental Surgery Duke University Medical Center Medical Physics Graduate Program Duke University Durham NC 27708 United States

ISBN: (纸本)1424415098

Current mammographic screeningfor breast cancer is less effective for younger women. To complement mammography for premenopausal women, we investigated the feasibility screening test using 98 blood serum proteins. Because the data set was very noisy and contained only weak features, we used a classifier designed for noisy data: decision fusion. Decision fusion outperformed both a support vector machine (SVM) and linear regression with forward stepwise feature selection on all three two-class classification tasks: normal tissue vs. cancer, normal tissue vs. benign lesions, and benign lesions vs. cancer. Decision fusion detected cancer moderately well (AUC=0.84 on normal vs. cancer), demonstrating promise as a screening tool. Decision fusion also detected benign lesions similarly well (AUC=0.83 on normal vs. benign lesions) and was the only classifier to achieve any success in separating benign from malignant lesions (AUC=0.64 on benign vs. cancer). The classification results suggest that the assayed proteins are more indicative of a secondary effect, such as immune response, rather than specific for breast cancer. In conclusion, the decision fusion classifier demonstrated some promise in detecting breast lesions and outperformed other classifiers, especially for the very noisy classification problem of distinguishing benign from malignant lesions. ©2007 IEEE.

关键词： Tissue

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AlzPharm: Integration of neurodegeneration data using RDF

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BMC bioinformatics 2007年第SUPPL. 3期8卷 1-12页

作者： Lam, Hugo Y.K. Marenco, Luis Clark, Tim Gao, Yong Kinoshita, June Shepherd, Gordon Miller, Perry Wu, Elizabeth Wong, Gwendolyn T. Liu, Nian Crasto, Chiquito Morse, Thomas Stephens, Susie Cheung, Kei-Hoi Interdepartmental Program in Computational Biology and Bioinformatics Yale University New Haven CT United States Center for Medical Informatics Yale University New Haven CT United States Department of Anesthesiology Yale University New Haven CT United States Department of Neurobiology Yale University New Haven CT United States Department of Molecular Cellular and Developmental Biology Yale University New Haven CT United States Department of Genetics Yale University New Haven CT United States Department of Computer Science Yale University New Haven CT United States Initiative in Innovative Computing Harvard University Cambridge MA United States Massachusetts General Hospital Boston MA United States Alzheimer Research Forum Burlington MA United States Oracle Burlington MA United States

Background: Neuroscientists often need to access a wide range of data sets distributed over the Internet. These data sets, however, are typically neither integrated nor interoperable, resulting in a barrier to answering complex neuroscience research questions. Domain ontologies can enable the querying heterogeneous data sets, but they are not sufficient for neuroscience since the data of interest commonly span multiple research domains. To this end, e-Neuroscience seeks to provide an integrated platform for neuroscientists to discover new knowledge through seamless integration of the very diverse types of neuroscience data. Here we present a Semantic Web approach to building this e-Neuroscience framework by using the Resource Description Framework (RDF) and its vocabulary description language, RDF Schema (RDFS), as a standard data model to facilitate both representation and integration of the data. Results: We have constructed a pilot ontology for BrainPharm (a subset of SenseLab) using RDFS and then converted a subset of the BrainPharm data into RDF according to the ontological structure. We have also integrated the converted BrainPharm data with existing RDF hypothesis and publication data from a pilot version of SWAN (Semantic Web Applications in Neuromedicine). Our implementation uses the RDF Data Model in Oracle Database 10g release 2 for data integration, query, and inference, while our Web interface allows users to query the data and retrieve the results in a convenient fashion. Conclusion: Accessing and integrating biomedical data which cuts across multiple disciplines will be increasingly indispensable and beneficial to neuroscience researchers. The Semantic Web approach we undertook has demonstrated a promising way to semantically integrate data sets created independently. It also shows how advanced queries and inferences can be performed over the integrated data, which are hard to achieve using traditional data integration approaches. Our pilot results su

关键词： Data integration

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Modeling protein interaction network and mechanisms in exocytosis

Modeling protein interaction network and mechanisms in exocy...

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IEEE Symposium on bioinformatics and Bioengineering (BIBE)

作者： Wen Zhou Tian Xia Jiansong Tong Julie Dickerson Bo Su Xun Gu Department of Mathematics Iowa State University Ames IA USA Program of Bioinformatics and computational biology Iowa State University Ames IA USA Department of Biochemistry Iowa State University Ames IA USA Department of Mathematics Iowa State University Ames IA Department of Genetics Iowa State University Ames IA USA

关键词： Proteins Mathematical model Biochemistry Neurotransmitters Endocrine system Computer networks Differential equations Mathematics Parameter estimation Stability analysis

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Comparing Kernels for Predicting Protein Binding Sites from Amino Acid Sequence

Comparing Kernels for Predicting Protein Binding Sites from ...

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International Joint Conference on Neural Networks (IJCNN)

作者： Feihong Wu B. Olson D. Dobbs V. Honavar Bioinformatics and Computational Biology Graduate Program Center for Computational Intelligence Learning and Discovery Iowa State University Ames IA USA

The ability to identify protein binding sites and to detect specific amino acid residues that contribute to the specificity and affinity of protein interactions has important implications for problems ranging from rational drug design to analysis of metabolic and signal transduction networks. Support vector machines (SVM) and related kernel methods offer an attractive approach to predicting protein binding sites. An appropriate choice of the kernel function is critical to the performance of SVM. Kernel functions offer a way to incorporate domain-specific knowledge into the classifier. We compare the performance of three types of kernels functions: identity kernel, sequence-alignment kernel, and amino acid substitution matrix kernel in the case of SVM classifiers for predicting protein-protein, protein-DNA and protein-RNA binding sites. The results show that the identity kernel is quite effective in on all three tasks. The substitution kernel based on amino acid substitution matrices that take into account structural or evolutionary conservation or physicochemical properties of amino acids yields modest improvement.

关键词： Kernel Proteins Amino acids Support vector machines Support vector machine classification Matrices Drugs Signal design Signal analysis Signal processing

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Breaking the high-throughput bottleneck

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Scientific Computing 2006年第4期23卷 22-26页

作者： Waters, Katrina M. Singhal, Mudita Webb-Robertson, Bobbie-Jo M. Stephan, Eric G. Gephart, Julie M. Computational Biology and Bioinformatics Groups United States Lab's Systems Biology Program Biological Sciences Division United States PNNL United States

The development of high-throughput (HTP) technologies such as transcriptomics (microarrays) and proteomics has made a revolution in the medical industry. PNNL is developing a systems biology computational framework using a problem-solving environment called bioinformatics Resource Manager (BRM) that automates routine data-merging and data-mining methods, and provides seamless linkage to data visualization tools. The BRM is designed to be operated by biologists looking for greater insights into their experimental results. BRM uses Remote Method Invocation (RMI) to launch several external data analysis tools, including NCBI's PubMed, the Conserved Domain Architectural Retrieval Tool (CDART) and the Basic Local Alignment Search Tool (BLAST). PQuad is a proteomics visualization tool that combines DNA or RNA sequence and proteomics data at multiple resolutions. It enables visualization of the data at the chromosome, gene and sequence levels.

关键词： Data visualization

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