A robust method for estimating gene expression states using Affymetrix microarray probe level data
| Autor: | Naomi Kamei, Keiko Otani, Kenichi Satoh, Eiso Hiyama, Keiko Hiyama, Megu Ohtaki |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Candidate gene
Gene Expression Biology lcsh:Computer applications to medicine. Medical informatics Biochemistry Neuroblastoma Structural Biology Databases Genetic Research article Gene expression Humans Gene Molecular Biology lcsh:QH301-705.5 Oligonucleotide Array Sequence Analysis Genetics Genome Human Microarray analysis techniques Gene Expression Profiling Applied Mathematics Computer Science Applications Gene expression profiling lcsh:Biology (General) Gene chip analysis lcsh:R858-859.7 Human genome DNA microarray |
| Zdroj: | BMC Bioinformatics, Vol 11, Iss 1, p 183 (2010) BMC Bioinformatics |
| ISSN: | 1471-2105 |
| Popis: | Background Microarray technology is a high-throughput method for measuring the expression levels of thousand of genes simultaneously. The observed intensities combine a non-specific binding, which is a major disadvantage with microarray data. The Affymetrix GeneChip assigned a mismatch (MM) probe with the intention of measuring non-specific binding, but various opinions exist regarding usefulness of MM measures. It should be noted that not all observed intensities are associated with expressed genes and many of those are associated with unexpressed genes, of which measured values express mere noise due to non-specific binding, cross-hybridization, or stray signals. The implicit assumption that all genes are expressed leads to poor performance of microarray data analyses. We assume two functional states of a gene - expressed or unexpressed - and propose a robust method to estimate gene expression states using an order relationship between PM and MM measures. Results An indicator 'probability of a gene being expressed' was obtained using the number of probe pairs within a probe set where the PM measure exceeds the MM measure. We examined the validity of the proposed indicator using Human Genome U95 data sets provided by Affymetrix. The usefulness of 'probability of a gene being expressed' is illustrated through an exploration of candidate genes involved in neuroblastoma prognosis. We identified the candidate genes for which expression states differed (un-expressed or expressed) when compared between two outcomes. The validity of this result was subsequently confirmed by quantitative RT-PCR. Conclusion The proposed qualitative evaluation, 'probability of a gene being expressed', is a useful indicator for improving microarray data analysis. It is useful to reduce the number of false discoveries. Expression states - expressed or unexpressed - correspond to the most fundamental gene function 'On' and 'Off', which can lead to biologically meaningful results. |
| Databáze: | OpenAIRE |
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