How to decide? Different methods of calculating gene expression from short oligonucleotide array data will give different result

Background: Short oligonucleotide arrays for transcript profiling have been available for several years. Generally, raw data from these arrays are analysed with the aid of the Microarray Analysis Suite or GeneChip Operating Software (MAS or GCOS) from Affymetrix. Recently, more methods to analyse the raw data have become available. Ideally all these methods should come up with more or less the same results. We set out to evaluate the different methods and include work on our own data set, in order to test which method gives the most reliable results. Results: Calculating gene expression with 6 different algorithms (MAS5, dChip PMMM, dChip PM, RMA, GCRMA and PDNN) using the same (Arabidopsis) data, results in different calculated gene expression levels. Consequently, depending on the method used, different genes will be identified as differentially regulated. Surprisingly, there was only 27 to 36% overlap between the different methods. Furthermore, 47.5% of the genes/ probe sets showed...

• Type: Journal
• Year: 2006
• Where: BMCBI
• Authors: Frank F. Millenaar, John Okyere, Sean T. May, Martijn van Zanten, Laurentius A. C. J. Voesenek, Anton J. M. Peeters
• Keywords: BMCBI 2006, Gene Expression, Raw Data, Real Time RT-PCR