Olivia Judson has a series of interesting posts on mutation over at her NYT blog The Wild Side:
Mutations that alter proteins have been linked to specific changes in a huge number of traits in organisms from bacteria to humans. Yet the proportion of a genome that contains the instructions to make proteins is tiny; in humans, it may be less than 2 percent. So there’s a lot of other DNA that will experience mutations. The question is, what might such mutations do?
Here’s one possibility. We know that some of that 98 percent is involved not in making proteins, but in regulating where and when the genes they are made from will get switched on. The biology of this gets pretty complicated — but what it amounts to is that most genes have an elaborate control region — a set of on/off switches officially known as cis-regulatory elements. When the right switches are on, the protein gets made; when they are off, it doesn’t. So mutations to the switches can alter how the protein is deployed. Then, the protein stays the same shape as it was before, but instead of being made in, say, just the liver, it starts being made somewhere else as well.
Also see here and here. Also her television documentary based on her book Dr. Tatiana’s Sex Advice to All Creation: The Definitive Guide to the Evolutionary Biology of Sex seems quite entertaining. Here is a segment.