How do the two alligators shown below differ?
At first the answer seems very easy. One has normal coloration. The other has abnormal coloration. But why do they have different coloration? The answer is in the alligators' genes. Genes carry the information needed by cells to produce proteins, and proteins can affect traits in various ways. In this example variation in the proteins in skin pigments give rise to different coloration. So how do genes, which are made up of DNA, determine which protein gets made?
Protein synthesis is the process in which cells build proteins. There are two main steps in protein synthesis: transcription and translation. Let's first look at transcription.