Affymetrix control genes plus links
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@patricia-luiza-nunes-da-costa-2595
Last seen 10.2 years ago
Dear colleagues, We are trying to analyze a group of Affymetrix arrays, but we don?t have experience. We performed the RMA normalization and after we analyzed with the algorithm SOM (3x3 Expander), among others. We observed that some control genes was differentially expressed in 2/12 arrays (cluster in: http://www.divshare.com/download/4105386-853), and it shoudn't, isn't it? The QC stats plot (simpleaffy) seemed good (http://www.divshare.com/download/4105385-181), and all parameters indicated by Affymetrix showed results acceptable. Do you think we have a bug in the experiment? Should we compare this 2 ?different? arrays with the others? Or can we correct this? Thanks for your help! Patricia Patr?cia Luiza Nunes da Costa Laborat?rio de Oncologia Experimental, Grupo de Ades?o Celular Faculdade de Medicina da Universidade de Paulo-FM USP Av. Dr. Arnaldo, 455 sala 4112 Cerqueira Cesar Cep 01246-903 Tel: (11) 3061-7486 e (11) 8202-7073 -------------------------- Esta mensagem foi verificada pelo sistema de antiv?rus DIM e acredita-se estar livre de Virus.
Normalization Normalization • 954 views
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Entering edit mode
@patricia-luiza-nunes-da-costa-2595
Last seen 10.2 years ago
Thanks for your answers Michal and Jeanette, I did the analysis with Affy Expression Console. They are at http://www.divshare.com/download/4115598-f93 The Pearson?s correlation showed 2 or 3 arrays that could be outliers, but I don?t know what is the limit to consider if they are outliers or not (the values are very near), do you know? I observed that many probesets follow the controls' pattern, the fluorescence intensity are lower in all array (Log probe cel intensity: http://www.divshare.com/download/4115603-454). The images of the chips are good; I think there isn?t any damage. We performed the same processing, scanning etc Where about what Jeanette said, the internal controls didn?t seem very different, especially GAPDH (http://www.divshare.com/download/4115599-597), maybe she have reason and I shouldn?t worry about it. What do you think people? All the best, Patricia > Patricia, > > The control probe sets are spiked in. It could just be a pipetting error > during labeling / hybridization. Notice that the beta-Actin probe sets are > OK. Don't worry about it. Check the Gapdh probe sets (these may vary under > certain conditions, but usually don't). > > Jeanette McClintick, PhD > Indiana University School of Medicine > Center for Medical Genomics > Indianapolis, IN > 317-274-8488 > jnmcclin at iupui.edu > > -----Original Message----- > From: bioconductor-bounces at stat.math.ethz.ch > [mailto:bioconductor-bounces at stat.math.ethz.ch] On Behalf Of Patr?cia > Luiza > Nunes da Costa > Sent: Wednesday, March 26, 2008 9:24 AM > To: bioconductor at stat.math.ethz.ch > Subject: [BioC] Affymetrix control genes plus links > > Dear colleagues, > > We are trying to analyze a group of Affymetrix arrays, but we don?t have > experience. We performed the RMA normalization and after we analyzed with > the algorithm SOM (3x3 Expander), among others. > We observed that some control genes was differentially expressed in 2/12 > arrays (cluster in: http://www.divshare.com/download/4105386-853), > and it shoudn't, isn't it? > The QC stats plot (simpleaffy) seemed good > (http://www.divshare.com/download/4105385-181), > and all parameters indicated by Affymetrix showed results acceptable. > > Do you think we have a bug in the experiment? > > Should we compare this 2 ?different? arrays with the others? Or can we > correct this? > > Thanks for your help! > > Patricia > > > > Patr?cia Luiza Nunes da Costa > Laborat?rio de Oncologia Experimental, Grupo de Ades?o Celular > Faculdade de Medicina da Universidade de Paulo-FM USP > Av. Dr. Arnaldo, 455 sala 4112 > Cerqueira Cesar > Cep 01246-903 > Tel: (11) 3061-7486 e (11) 8202-7073 > > > > -------------------------- > Esta mensagem foi verificada > pelo sistema de antiv?rus DIM e > acredita-se estar livre de Virus. > > _______________________________________________ > 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 > > > -------------------------- > Esta mensagem foi verificada > pelo sistema de antiv?rus DIM e > acredita-se estar livre de Virus. > Patr?cia Luiza Nunes da Costa Laborat?rio de Oncologia Experimental, Grupo de Ades?o Celular Faculdade de Medicina da Universidade de Paulo-FM USP Av. Dr. Arnaldo, 455 sala 4112 Cerqueira Cesar Cep 01246-903 Tel: (11) 3061-7486 e (11) 8202-7073 -------------------------- Esta mensagem foi verificada pelo sistema de antiv?rus DIM e acredita-se estar livre de Virus.

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