Microarray technology,widely used for gene expression profiling,can be used to investigate the cellular role of all genes,identify new drug targets and discover new methods to characterize and treat complex disease.Applied Biosystems introduces a complete system to detect low levels of gene expression based on chemiluminescent detection on novel microarrays.Two significant features of this system are the use of a highly annotated list of human genes that were used in the design of the 60-mer oligonucleotide probes found on the microarrays and the extensive annotation data that is supplied for each of the 31,097 genes targeted by the microarray probes.This talk will show how to transition from global expression profiling on microarrays to a more focused set of candidate genes using the Applied Biosystems Expression Array System,the Celera Discovery SystemTM and Assays-on-DemandTM gene expression products.