Microarrays can be used for evaluating thousands of genes at one time. A simple red, green or yellow dot can tell us many things about genes. Each dot represents a different gene and each color represents how the gene is expressed in the cells of the scientists choosing. For example, perhaps the scientist is experimenting with normal skin cells and cancerous skin cells. If the dot for a certain gene is green that means it is expressed in healthy cells but not in cancerous cells. If the dot is red, it is expressed only in cancerous cells. Finally, if the dot is yellow, it is expressed in both healthy and cancerous cells and therefore probably has nothing to do with the cancer.
We experimented with healthy lung cells and cancerous lung cells. We had 6 different genes that we were testing. We carefully pipetted all 6 genes into their places on the microarray slide, and then added a dye which changed colors to either red, blue or purple. Then we exami
ned each space for its involvement in the cancer. The genes that are only expressed in healthy cells are somehow involved in the cancer because for whatever reason they are not being expressed in the cancerous cells. Therefore the only genes not involved in the cancer were the ones that showed up as a combination of red and blue.
