Comparison of expression profiles of once and three time linearly amplified samples

In order to assess the impact of three rounds of linear amplification on the technical reproducibility of gene expression measurements, we performed twelve microarray experiments. We analysed mouse RNA from cortex, cerebellum and liver from one individual. One RNA sample of 5µg from each of the three different tissues was processed according to the standard Affymetrix protocol and hybridized onto mouse gene expression arrays MG_U74Av2. Three additional samples from each tissue of 1ng were processed according to a modified procedure that involves three linear amplifications before hybridization onto the microarray chips. One mouse was analysed. One RNA sample of 5µg from each of liver, cortex, and cerebellum were processed according to the standard Affymetrix protocol and hybridized onto mouse gene expression arrays MG_U74Av2. Three additional samples (technical replicates) from each tissue of 1ng were processed according to a modified procedure that involves three linear amplifications before hybridization onto the microarray chips, resulting in 12 microarray experiments.