(Also called DNA micro-array technology)
One of the important capabilities of DNA is the ability of a single strand of DNA to match up and pair with another strand of DNA or RNA that has a complementary sequence of nucleotides (remember that A’s bind to T’s and C’s bind to G’s). This ability has many practical benefits for biological scientists. One of these is the use of solid supports (such as glass microscope slides) to carry many different patches or spots of DNA, each consisting of different single-strands of DNA containing known sequences of nucleotides. These arrays of DNA patches on a solid support are known as gene-chips. The ability of these DNA patches to capture specific complementary RNAs provides a way of measuring the levels of many different mRNA molecules in a sample. Measurement of specific matching of captured RNA to patches on the gene-chip corresponding to different genes provides a method for simultaneously tracking the activities of many different genes in a tissue or cell sample. This method is providing large amounts of new information to biologists about what happens in living organisms.