With the successful completion of the Human Genome Project, research attention is increasingly focusing on proteins -- the versatile products produced from genetic templates. Protein microarrays are helping researchers develop early detection methods, particularly for chronic diseases. As discussed in a special feature in this week’s Science, Joshua LaBaer's group at Arizona State University has developed a novel protein array. Known as Nucleic Acid Programmable Protein Array or NAPPA, the technique is particularly powerful because it obviates the need to purify proteins prior to their use in a microarray. Instead of using the protein itself, the NAPPA technique spots protein-coding circular pieces of DNA known as plasmids -- the blueprints for building proteins -- onto slides, bringing the simplicity and low cost of DNA microarray technology into the world of proteomics.