contrast matrix in LIMMA
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@erika-melissari-2798
Last seen 10.2 years ago
Hello all, by using LIMMA package I'm setting the contrast matrix to discover differentially expressed genes in a dual-color microarray experiment. In this experiment I observed the expression levels of mRNA samples of three different phenotypes compared to the expression levels of a wild-type sample. My experimental design is a reference design that is each mRNA sample is hybridized onto the same array with the wild type sample, and a dye-swap for each array is realized. Phenotype 1: mRNA1.1 (green) à WT (red) mRNA1.1 (red) à WT (green) mRNA1.2 (green) à WT (red) mRNA1.2 (red) à WT (green) And so on Phenotype 2: mRNA2.1 (green) à WT (red) mRNA2.1 (red) à WT (green) mRNA2.2 (green) à WT (red) mRNA2.2 (red) à WT (green) And so on Phenotype 3: mRNA3.1 (green) à WT (red) mRNA3.1 (red) à WT (green) mRNA3.2 (green) à WT (red) mRNA3.2 (red) à WT (green) And so on I'm interested in determining differentially expressed genes for each phenotype respect to WT sample that is "Phenotype 1" àWT, "Phenotype 2" àWT, "Phenotype 3" àWT. Moreover, I'm interested in determining the differentially expressed genes in commom between each couple of phenotypes that is"Phenotype 1" à"Phenotype 2", "Phenotype 1" à"Phenotype 3", "Phenotype 2" à"Phenotype 3". Does anyone know how I can set the contrast matrix to be inserted in lmFit function? What is the model to be used? Thank you for your help Erika [[alternative HTML version deleted]]
Microarray limma Microarray limma • 1.1k views
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@erika-melissari-2798
Last seen 10.2 years ago
Hello all, by using LIMMA package I'm setting the contrast matrix to discover differentially expressed genes in a dual-color microarray experiment. In this experiment I observed the expression levels of mRNA samples of three different phenotypes compared to the expression levels of a wild-type sample. My experimental design is a reference design that is each mRNA sample is hybridized onto the same array with the wild type sample, and a dye-swap for each array is realized. Phenotype 1: mRNA1.1 (green) à WT (red) mRNA1.1 (red) à WT (green) mRNA1.2 (green) à WT (red) mRNA1.2 (red) à WT (green) And so on Phenotype 2: mRNA2.1 (green) à WT (red) mRNA2.1 (red) à WT (green) mRNA2.2 (green) à WT (red) mRNA2.2 (red) à WT (green) And so on Phenotype 3: mRNA3.1 (green) à WT (red) mRNA3.1 (red) à WT (green) mRNA3.2 (green) à WT (red) mRNA3.2 (red) à WT (green) And so on I'm interested in determining differentially expressed genes for each phenotype respect to WT sample that is "Phenotype 1" àWT, "Phenotype 2" àWT, "Phenotype 3" àWT. Moreover, I'm interested in determining the differentially expressed genes in commom between each couple of phenotypes that is"Phenotype 1" à"Phenotype 2", "Phenotype 1" à"Phenotype 3", "Phenotype 2" à"Phenotype 3". Does anyone know how I can set the contrast matrix to be inserted in lmFit function? What is the model to be used? Thank you for your help Erika [[alternative HTML version deleted]]
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Dear Erika, Have you read through the limma vignette? limmaUsersGuide() . It seems like you have a combination of section 7.3 Common Reference Designs and 8.2 Technical Replication. Please read through these, and if you're still having trouble, write back with examples of the design and contrast matrices you've tried, and why you think they are or are not working. Good luck, Jenny At 03:23 AM 9/15/2008, Erika Melissari wrote: >Content-Type: text/plain >Content-Disposition: inline >Content-length: 1594 > >Hello all, > > >by using LIMMA package I'm setting the contrast >matrix to discover differentially expressed >genes in a dual-color microarray experiment. > >In this experiment I observed the expression >levels of mRNA samples of three different >phenotypes compared to the expression levels of a wild-type sample. > >My experimental design is a reference design >that is each mRNA sample is hybridized onto the >same array with the wild type sample, and a >dye-swap for each array is realized. > > > >Phenotype 1: > > > >mRNA1.1 (green) ? WT (red) > >mRNA1.1 (red) ? WT (green) > > > >mRNA1.2 (green) ? WT (red) > >mRNA1.2 (red) ? WT (green) > > > >And so on > > > >Phenotype 2: > > > >mRNA2.1 (green) ? WT (red) > >mRNA2.1 (red) ? WT (green) > > > >mRNA2.2 (green) ? WT (red) > >mRNA2.2 (red) ? WT (green) > > > >And so on > > > >Phenotype 3: > > > >mRNA3.1 (green) ? WT (red) > >mRNA3.1 (red) ? WT (green) > > > >mRNA3.2 (green) ? WT (red) > >mRNA3.2 (red) ? WT (green) > > > >And so on > > > >I'm interested in determining differentially >expressed genes for each phenotype respect to WT >sample that is "Phenotype 1" ?WT, "Phenotype 2" ?WT, "Phenotype 3" ?WT. > >Moreover, I'm interested in determining the >differentially expressed genes in commom between >each couple of phenotypes that is"Phenotype 1" >?"Phenotype 2", "Phenotype 1" ?"Phenotype 3", "Phenotype 2" ?"Phenotype 3". > >Does anyone know how I can set the contrast >matrix to be inserted in lmFit function? > >What is the model to be used? > > >Thank you for your help > >Erika > > [[alternative HTML version deleted]] > > >_______________________________________________ >Bioconductor mailing list >Bioconductor at stat.math.ethz.ch >https://stat.ethz.ch/mailman/listinfo/bioconductor >Search the archives: >http://news.gmane.org/gmane.science.biology.informatics.conductor Jenny Drnevich, Ph.D. Functional Genomics Bioinformatics Specialist W.M. Keck Center for Comparative and Functional Genomics Roy J. Carver Biotechnology Center University of Illinois, Urbana-Champaign 330 ERML 1201 W. Gregory Dr. Urbana, IL 61801 USA ph: 217-244-7355 fax: 217-265-5066 e-mail: drnevich at illinois.edu
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