Hi, I have samples put onto 2 different chip types (MOE430.2 and MOE430A) which are part of the same experiment. I would like add the MOE430.2 arrays to the MOE430A affybatch before normalization. Otherwise, I could combine the previously normalized values. Wouldn't the normalization of the samples together (after combining the affybatch raw probe values) be best in this case ? What is the most efficient way to add the raw probe signals to an affybatch? Lana Schaffer Biostatistics/Informatics The Scripps Research Institute DNA Array Core Facility La Jolla, CA 92037 (858) 784-2263 (858) 784-2994 schaffer at scripps.edu