Gene array analysis: A way of analyzing the differential expression of thousands of species of mRNA (messenger RNA) at the same time in two different samples (as, for example, in normal vs. tumor tissue, or at different developmental stages). Gene array analysis involves synthesizing labeled cDNA (complementary DNA) from 2 or more sources, and hybridizing them to identical gene arrays. This procedure can be done in standard molecular biology laboratories with basic instrumentation.
Gene array analysis is an extraordinarily powerful tool in molecular biology today and is expected to shape the molecular medicine of tomorrow. Many diseases will be defined in a "customized" fashion according to the array of genes in the particular patient affected. Not only diseases, but also optimal treatments, will be put into discrete categories according to the diagnostic gene array of the person being evaluated. Medicine will not be practiced in the same way in 2050 as it was in 2000, thanks in part to gene array analysis.