The Brilliant Invention of DNA Microarray

Due to the advances of DNA technology, many techniques have been invented to help us to solve problems at genetic levels at a more accurate and faster manner. One of the brilliant inventions is the DNA microarray. With this method, researchers are able to test thousands of genes simultaneously to determine which ones are expressed in a particular tissue under different environmental conditions, in various disease states or at different developmental stages. For example, we can use DNA microarray to detect genes that are responsible for breast cancer. We can compare the gene expression in a healthy breast tissue and a breast cancer tissue. First, we isolate the mRNA in the healthy breast tissue and breast cancer tissue. Then, by using reverse transcriptase, red fluorescently labeled cDNA is synthesized from the mRNA from the healthy breast issue while green dye fluorescently labeled cDNA is synthesized from the breast cancer tissue. Then we put the cDNA mixture into the microarray which consists of all the human genes and allow hybridization. In the microarray, red dyes represent genes that are expressed in the healthy tissue (or more than green dyes), green dyes represent genes that are expressed in the cancer tissue (or more than red dye) while yellow are the ones that have equal amounts of red and green dyes. However, we are interested in the green dyes as these are the genes that might be responsible for causing cancer. By knowing these genes, we can develop drugs to treat those breast cancer patients. This is a breakthrough as genes that are responsible for many diseases such as AIDS can be detected by using this method and therefore can help millions of people by studying these genes.