Systems Biology Commons^™

Micrat: A Novel Algorithm For Inferring Gene Regulatory Networks Using Time Series Gene Expression Data, Bei Yang, Yaohui Xu, Andrew Maxwell, Wonryull Koh, Ping Gong, Chaoyang Zhang

Faculty Publications

Background: Reconstruction of gene regulatory networks (GRNs), also known as reverse engineering of GRNs, aims to infer the potential regulation relationships between genes. With the development of biotechnology, such as gene chip microarray and RNA-sequencing, the high-throughput data generated provide us with more opportunities to infer the gene-gene interaction relationships using gene expression data and hence understand the underlying mechanism of biological processes. Gene regulatory networks are known to exhibit a multiplicity of interaction mechanisms which include functional and non-functional, and linear and non-linear relationships. Meanwhile, the regulatory interactions between genes and gene products are not spontaneous since various …

Development, Evaluation, And Application Of A Novel Error Correction Method For Next Generation Sequencing Data, Isaac Akogwu

Dissertations

Tremendous evolvement in sequencing technologies and the vast availability of data due to decreasing cost of Next-Generation-Sequencing (NGS) has availed scientists the opportunity to address a wide variety of evolutionary and biological issues. NGS uses massively parallel technology to accelerate the process at the expense of accuracy and read length in comparison to earlier Sanger methods. Therefore, computational limitations exist in how much analysis and information can be gleaned from the data without performing some form of error correction.

Error correction process is laborious and consumes a lot of computational resources. Despite the existence of many NGS data error correction …

Phylogenetic Relationships Of Samydaceae And Taxonomic Revision Of The Species Of Casearia In South-Central Asia, Tharangamala Samarakoon

Dissertations

The flowering plant family Samydaceae was recently reinstated to include 14 genera and about 256 species of tropical trees and shrubs. Preliminary analyses of relationships in the family, however, indicated that the largest genus in the family, Casearia, is not monophyletic and that several smaller groups are probably misplaced. In order to affirm or refute those hypotheses, additional DNA sequence data with broader taxon sampling from the Old World were gathered for phylogenetic analysis. In particular, rapidly evolving plastid (matK, ndhF, psbA-trnH, trnL, and trnL-F) and nuclear (EMB2765 and GBSSI) DNA …

State Space Model With Hidden Variables For Reconstruction Of Gene Regulatory Networks, Xi Wu, Peng Li, Nan Wang, Ping Gong, Edward J. Perkins, Youping Deng, Chaoyang Zhang

Faculty Publications

Background: State Space Model (SSM) is a relatively new approach to inferring gene regulatory networks. It requires less computational time than Dynamic Bayesian Networks (DBN). There are two types of variables in the linear SSM, observed variables and hidden variables. SSM uses an iterative method, namely Expectation-Maximization, to infer regulatory relationships from microarray datasets. The hidden variables cannot be directly observed from experiments. How to determine the number of hidden variables has a significant impact on the accuracy of network inference. In this study, we used SSM to infer Gene regulatory networks (GRNs) from synthetic time series datasets, investigated …

A Novel Gene Network Inference Algorithm Using Predictive Minimum Description Length Approach, Vijender Chaitankar, Preetam Ghosh, Edward J. Perkins, Ping Gong, Youping Deng, Chaoyang Zhang

Faculty Publications

Background: Reverse engineering of gene regulatory networks using information theory models has received much attention due to its simplicity, low computational cost, and capability of inferring large networks. One of the major problems with information theory models is to determine the threshold which defines the regulatory relationships between genes. The minimum description length (MDL) principle has been implemented to overcome this problem. The description length of the MDL principle is the sum of model length and data encoding length. A user-specified fine tuning parameter is used as control mechanism between model and data encoding, but it is difficult to …

The Effects Of Climate Variability On The Structure Of The Phytoplankton Community In Tumaco Bay, Colombia, Ingrid Garcia-Hansen Honkala

Dissertations

Spatiotemporal variability in the diatom and dinoflagellate community structure and chlorophyll a (chl a) concentrations in Tumaco Bay during the 1993-2005 period was related clearly to seasonal and interannual variability in environmental conditions due to the migration of the Inter-tropical Convergence Zone (ITZC) and the influence of El Nino Southern Oscillation (ENSO) events. A total of 134 species of diatoms that belong to 57 genera, and 78 species of dinoflagellates that belong to 25 genera were identified during the survey. The diatom community was the dominant group in the waters of the bay, being the most abundant with the greatest …