In one of my many weird ideas, I decided to start GMing a game of my own design on both the giantitp.com and erfworld.com forums called BioHazard. The basic idea of the game is that the players are trapped on a planet, with a rocket that can carry 2 people, guarded by significant defenses. They have to gather creatures called batopods, research methods of breeding and mutating them to make them more powerful, gather resources to build their base and batopod capacity, and eventually try to destroy the defenses around the rocket and escape.
I'm still playing around with many of the concepts and looking for a good balance. I am currently using a 32 character genetic code for each batopod. There are combinations of nucleotides that create certain genes, expressed by the batopod. For example, a certain gene sequence results in improved melee attack. A creature with this gene sequence can hit more readily and do more melee damage. Similarly, a batopod with two such genes would be better than one with only one gene. The main driving force of the game will be breeding. cloning, and mutating batopods to get the untilmate creatures. I've seen traits as high as 4 in randomly generated batopods, and theoretically, a 2 nucleotide trait could be replicated 16 times, while a 3 could be replicated 10 times (more if some nucleotides can overlap).
If you are interested in player or seeing this in action, look at my two games:
Send me a PM in either forum if you would like to play.