Most organisms have far more genetic material than is strictly necessary to "build" that creature.

For example, it was previously estimated that you could make a human with only 2% of our actual genetic code. The rest was "junk" DNA.

Of course, this is ridiculous. I am a firm believer in Chesterton's parable about removing a seemingly pointless gate in the middle of the road. If you can't explain the function of a specific gene, then don't tell me it is useless junk. When you can tell me how and why that gene came to be incorporated in the full genetic code of an organism, then I MIGHT believe you when you tell me exactly what all of the genes do in concert.

One hundred years in the future, people will laugh at what we currently believe is "settled science" about genetics.