To do this, the scientist would obtain fragments of the gene and deposit DNA bits onto a piece of glass about the size of a microscope slide. Once the DNA chip is ready, the scientist would extract the active DNA from the diseased cell, and drop this genetic material onto the DNA chip. If the suspect gene is present, it will bind to the gene fragments on the chip. These connections are spotted by an instrument that works like a powerful microscope. The presence or absence of connections tells the researcher whether the suspect gene is involved in the disease, and that information guides further drug research.
Large scale is the operative term.
DeRisi said researchers can use hundreds or thousands of different gene fragments when making a DNA chip, and it makes no sense for them to create or store their own gene bits when it's easier to order them from the commercial warehouses. Incyte scientist Samuel LaBrie showed off the heart of the St. Louis operation, an office bay filled with 100 industrial freezers. Each freezer holds roughly half a million DNA clones, with each clone stored in a miniature plastic test tube. The cold helps extend the shelf life of the material. LaBrie said Incyte has a second, backup clone warehouse across town, in case an accident occurs at the main depot.