Project description:This study evaluates a resequencing microarray designed to determine the sequence of the four major genes in the Ebolavirus genome, Nucleoprotein (NP), matrix protein (VP40), glycoprotein (GP) and polymerase (L). The array has the ability to determine the sequence of five species and strains: Zaire Ebolavirus (Mayinga and Makona), Bundibugyo Ebolavirus, Sudan Ebolavirus and Tai Forest Ebolavirus.
Project description:A custom resequencing array for analysis of field isolates of plasmdium falciparum was created. Test of DNA with genotypes known at all loci genotyped by the microarray as well as test of accuracy correlation with amounts of DNA added to each array
Project description:Filoviruses are emerging pathogens that cause acute fever with high fatality rate and present a global public health threat. During the 2013-2016 Ebola virus outbreak, genome sequencing allowed the study of virus evolution, mutations affecting pathogenicity and infectivity, and tracing the viral spread. In 2018, early sequence identification of the Ebolavirus as EBOV in the Democratic Republic of the Congo supported the use of an Ebola virus vaccine. However, field-deployable sequencing methods are needed to enable a rapid public health response. Resequencing microarrays (RMA) are a targeted method to obtain genomic sequence on clinical specimens rapidly, and sensitively, overcoming the need for extensive bioinformatic analysis. This study presents the design and initial evaluation of an ebolavirus resequencing microarray (Ebolavirus-RMA) system for sequencing the major genomic regions of four Ebolaviruses that cause disease in humans. The design of the Ebolavirus-RMA system is described and evaluated by sequencing repository samples of three Ebolaviruses and two EBOV variants. The ability of the system to identify genetic drift in a replicating virus was achieved by sequencing the ebolavirus glycoprotein gene in a recombinant virus cultured under pressure from a neutralizing antibody. Comparison of the Ebolavirus-RMA results to the Genbank database sequence file with the accession number given for the source RNA and Ebolavirus-RMA results compared to Next Generation Sequence results of the same RNA samples showed up to 99% agreement.
Project description:BackgroundAlternative splicing is an important mechanism that increases protein diversity and functionality in higher eukaryotes. Affymetrix exon arrays are a commercialized platform used to detect alternative splicing on a genome-wide scale. Two probe summarization algorithms, PLIER (Probe Logarithmic Intensity Error) and RMA (Robust Multichip Average), are commonly used to compute gene-level and exon-level expression values. However, a systematic comparison of these two algorithms on their effects on high-level analysis of the arrays has not yet been reported.ResultsIn this study, we showed that PLIER summarization led to over-estimation of gene-level expression changes, relative to exon-level expression changes, in two-group comparisons. Consequently, it led to detection of substantially more skipped exons on up-regulated genes, as well as substantially more included (i.e., non-skipped) exons on down-regulated genes. In contrast, this bias was not observed for RMA-summarized data. By using a published human tissue dataset, we compared the tissue-specific expression and splicing detected by Affymetrix exon arrays with those detected based on expressed sequence databases. We found the tendency of PLIER was not supported by the expressed sequence data.ConclusionWe showed that the tendency of PLIER in detection of alternative splicing is likely caused by a technical bias in the approach, rather than a biological bias. Moreover, we observed abnormal summarization results when using the PLIER algorithm, indicating that mathematical problems, such as numerical instability, may affect PLIER performance.
Project description:This study evaluates a resequencing microarray designed to determine the sequence of the four major genes in the Ebolavirus genome, Nucleoprotein (NP), matrix protein (VP40), glycoprotein (GP) and polymerase (L). The array has the ability to determine the sequence of five species and strains: Zaire Ebolavirus (Mayinga and Makona), Bundibugyo Ebolavirus, Sudan Ebolavirus and Tai Forest Ebolavirus. Illumina Next Generation Sequencing verified the sequence of the Zaire Ebolavirus (Mayinga) sample.