Here is a paragraph from a white paper I was reading: Identifying genes is important, but it is equally important to characterize the proteins they encode. Primarily through systematic characterization of extracellular proteins secreted by GAS, Musser and his team have already identified more than 40 new proteins, and they are working to understand which ones are relevant to infection. Using microarrays, Musser discovered that nearly half of these proteins are upregulated during infection and therefore are good candidates for study. One of the new proteins, homologous to the alpha subunit of human Mac-1, inhibits the normal function of human neutrophils, which attach to and break down foreign cells. Such a protein is likely to assist the bacteria in evading destruction by the immune cells. My question is what information does a DNA microarray contain? Is it a subset or a specific set of DNA sequence? How can you find a specific external protein from the microarray since it is the DNA?