The genome is littered with old copies of genes and experiments that went wrong somewhere in the recent past—say, the last half a million years. This code is there but inactive. These are called the “pseudo genes”.
Furthermore, 97% of your DNA (Deoxyribonucleic Acid) is commented out. DNA is linear and read from start to end. The parts that should not be decoded are marked very clearly, much like C comments. The 3% that is used directly form the so called “exons”. The comments, that come “inbetween” are called “introns”.
These comments are fascinating in their own right. Like C comments they have a start marker, like /*, and a stop marker, like */. But they have some more structure. Remember that DNA is like a tape—the comments need to be snipped out physically! The start of a comment is almost always indicated by the letters “GC”, which thus corresponds to /*, the end is signalled by “AG”, which is then like */.
Via Reddit [1], “DNA seen through the eyes of a coder [2]”
It's an interesting view of DNA, as seen through the eyes of a programmer.
[1] http://programming.reddit.com/info/64dlz/comments/