Introduction:
A microarray is a tool that helps scientists look at thousands of genes at a time. This enables them to see to what extent the genes are expressed in certain tissues. Microarrays are commonly used to compare tissues. The mRNA extracted from the samples are labeled with colors such as red and green. The mRNA is then applied to the DNA chips and the spots on the microarrays show which genes are expressed. Whichever color appears on a certain spot shows whether the gene is on in that sample. Combinations can create (for example with red and green) yellow spots revealing that the gene is on in both of those samples. Intensity is also important because a dull red spot and a bright red spot are two different things. The bright one shows that the gene is turned on more than the dull one. A helpful analogy is to think of the spots like lights with dimmer switches. This can be applied to cancerous and noncancerous tissues to see which genes are on in each showing the difference between the two. We will be studying the expression of six different genes in normal lung and cancerous lung cells. The end results will show us which genes have been expressed to produce more RNA in cancerous lung cells and which genes have been repressed from producing mRNA in normal lung cells.
