How to determine characteristics for a genome?

Question

In AI, are there any simple and/or very visual examples of how one could implement a genome into a simulation?

Basically, I'm after a simple walkthrough (not a tutorial, but rather something of a summarizing nature) which details how to implement a genome which changes the characteristics in an 'individual' in a sumlation.

These genes would not be things like:

• Mass
• Strength
• Length,
• Etc..

But rather they should be the things defining the above things, abstracting the genome from the actual characteristics of the inhabitants of the simulation.

Am I clear enough on what I want?

Anyway, if there's any way that you have tried that's better, and that implements evolution in a form like these sexual swimmers, then by all means, go ahead and post it! The more fun inspiration the better :)