FAQ

Labeled cRNA targets are prepared in the core laboratory from either total RNA or purified polyA+ mRNA provided by the investigator.  Affymetrix has found that results obtained from either total RNA or polyA+ RNA are similar but not identical.  The core and others have also observed that different methods of RNA isolation can contribute to variation in the microarray assay.  Therefore, to get the best results, the core recommends using the same method of RNA isolation for all samples in a study.

See specific protocol information related to isolation of RNA from mammalian cells or tissues, yeast, quantification and precipitation of RNA and other RNA isolation considerations.