Bioinformatics Commons^™

A Study Of Correlations Between The Definition And Application Of The Gene Ontology, Yuji Mo

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

When using the Gene Ontology (GO), nucleotide and amino acid sequences are annotated by terms in a structured and controlled vocabulary organized into relational graphs. The usage of the vocabulary (GO terms) in the annotation of these sequences may diverge from the relations defined in the ontology. We measure the consistency of the use of GO terms by comparing GO's defined structure to the terms' application. To do this, we first use synthetic data with different characteristics to understand how these characteristics influence the correlation values determined by various similarity measures. Using these results as a baseline, we found that …

Gata-Family Transcription Factors In Magnaporthe Oryzae, Cristian F. Quispe

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The filamentous fungus, Magnaporthe oryzae, responsible for blast rice disease, destroys around 10-30% of the rice crop annually. Infection begins when the specialized infection structure, the appressorium, generates enormous internal turgor pressure through the accumulation of glycerol. This turgor acts on a penetration peg emerging at the base of the cell, causing it to breach the leaf surface allowing its infection.

The enzyme trehalose-6- phosphate synthase (Tps1) is a central regulator of the transition from appressorium development to infectious hyphal growth. In the first chapter we show that initiation of rice blast disease requires a regulatory mechanism involving an …

Protein Structure – Based Method For Identification Of Horizontal Gene Transfer In Bacteria, Swetha Billa

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

Horizontal Gene Transfer is defined as the movement of genetic material from one strain of species to another. Bacteria, being an asexual organism were always believed to transfer genes vertically. But recent studies provide evidence that shows bacteria can also transfer genes horizontally.

HGT plays a major role in evolution and medicine. It is the major contributor in bacterial evolution, enabling species to acquire genes to adapt to the new environments. Bacteria are also believed to develop drug resistance to antibiotics through the phenomenon of HGT. Therefore further study of HGT and its implications is necessary to understand the effects …

Functional Classification Of Divergent Protein Sequences And Molecular Evolution Of Multi-Domain Proteins, Pooja K. Strope

School of Biological Sciences: Dissertations, Theses, and Student Research

Transmembrane proteins and multi-domain proteins together make up more than 80% of the total proteins in any eukaryotic proteome. Therefore accurately classifying such proteins into functional classes is an important task. Furthermore, understanding the molecular evolution of multi-domain proteins is important because it shows how various domains fuse to form more complex proteins, and acquire new functions possibly affecting the organismal level of evolution. In this thesis, I first investigated the performance of several protein classifiers using one of the most divergent transmembrane protein families, the G-protein-coupled receptor (GPCR) superfamily, as an example. Alignment-free classifiers based on support vector machines …

Screening Synteny Blocks In Pairwise Genome Comparisons Through Integer Programming, Haibao Tang, Eric Lyons, Brent S. Pedersen, James C. Schnable, Andrew H. Paterson, Michael Freeling

Department of Agronomy and Horticulture: Faculty Publications

Background:

It is difficult to accurately interpret chromosomal correspondences such as true orthology and paralogy due to significant divergence of genomes from a common ancestor. Analyses are particularly problematic among lineages that have repeatedly experienced whole genome duplication (WGD) events. To compare multiple “subgenomes” derived from genome duplications, we need to relax the traditional requirements of “one-to-one” syntenic matchings of genomic regions in order to reflect “one-to-many” or more generally “many-to-many” matchings. However this relaxation may result in the identification of synteny blocks that are derived from ancient shared WGDs that are not of interest. For many downstream analyses, we …

Computational Complexity Of Approximate And Precise Data With Constraint Automaton, Dipty Singh

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

The DNA molecules packaged in structures called chromosomes within the cells of living organisms encode hereditary information that is passed on to their offspring. Using transcription and translation, the genes within these DNA molecules help in protein synthesis. Thus chromosomal DNA serves as a blueprint for the chemical processes of life.

In order to analyze a DNA sequence by currently available technology, we have to cut it into small fragments, e.g. by using restriction enzymes. The application of different restriction enzymes to the multiple copies of the same DNA sequence generates many overlapping fragments. In order to construct the original …

Computational Genomic Signatures And Metagenomics, Ozkan U. Nalbantoglu

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Mathematical characterizations of biological sequences form one of the main elements of bioinformatics. In this work, a class of DNA sequence characterization, namely computational genomics signatures, which capture global features of these sequences is used to address emerging computational biology challenges. Because of the species specificity and pervasiveness of genome signatures, it is possible to use these signatures to characterize and identify a genome or a taxonomic unit using a short genome fragment from that source. However, the identification accuracy is generally poor when the sequence model and the sequence distance measure are not selected carefully. We show that the …