Ask CNN: What's the Difference Between Mapping and Sequencing a Genome?
ANNOUNCER: Viewer Linda Loomis asks CNN, "There are the terms 'mapping the human genome' and 'sequencing the human genome.' What's the difference between mapping and sequencing our DNA? Or do these terms mean the same thing?</s>ANN KELLAN, CNN CORRESPONDENT: Linda, there is a difference between a map and a sequence. Think of the map as the big picture and the sequence as a very detailed look. Our human genome is made up of billions of chemical letters. Now, in those chemical letters are genes. These genes determine everything from how tall we are, the color of our eyes, the color of our skin to how well we fight diseases. Now, in a map, you get a look at the genes and generally where they are. We don't know yet all the genes on our genome. The sequence looks at each chemical letter and puts them in the right order, one after the other after the other. Now, this will help scientists find more genes, and it'll make it easier for them to figure out how these genes work and what they do. Now, this will help scientists figure out all the details about how we evolved, how we fight diseases, and knowing this will help us maybe get treatments for diseases much faster than we did before.