Translating genetic inheritance basics into a game

[viveleroi]

I'm currently working on a mac/pc game that allows you to explore a 2d world as an organism - you need to reproduce, attack and defend your way through an extremely vast ocean. Think "cell-stage" in Spore, but with a focus on strategy, genetics, multiplayer, etc.

 

Part of my goal is to keep the game based on as many realistic ideas as possible. However, it's been some time since I took genetics courses and I've been reading a lot to refresh my memory, but I need to clarify some aspects.

 

I understand the relationship between dominant/expressed and recessive/recessed, and I'm trying to mirror this system as best I can in the game. However, it doesn't fully translate to my setup so either I need to change my setup, or be flexible with how realistic the genetics portion is.

 

Here's an example:

 

There will eventually be hundreds of different traits - things that allow organisms to do different things (Plant digestion, Meat digestion, various defenses, immunities, metabolism, lifespan, and some fun ones). The only way to get those traits is to obtain the genes for them - primarily by reproducing with another organism. We already have expressed/recessed genes - and recessed genes need two copies before they become expressed.

 

However, we have some debate as to whether all dominant genes get passed from each parent to a child. I can't quite seem to get a solid answer to this - but part of the problem is that in real life, you usually have genes that are variations of a single trait - like short height versus tall height, or eye colors. In the game, at least when starting out, genes are introducing new abilities to you. As you reproduce, we need to figure out which genes to properly carry on.

 

So here's a full example of our logic:

 

Parent A has: Plant Digestion (level 1)

Parent B has: Poison Immunity (Level 2)

 

Those example traits are always expressed, for the sake of simplicity. Because each parent has only a single expressed trait and the other parent has no copy at all, how do I determine what carries over to the offspring? Would the offspring have both 100% of the time?

 

Internally, we've debated giving all organisms some variation of most of these (at least to mirror as the player earns them) so that there always will be a second copy - but that gets complicated because there will be so many different copies.

 

Throughout the game you need to be able to discover new genes, and selectively improve the levels of the traits you already have. But I want to minimize the risk of losing genes (right now, we just give it a 50/50 chance for each dominant trait from each parent) - this really kills the experience of the game because you work hard to get a trait, and it essentially has a 50/50 shot of vanishing next reproduction.

 

I appreciate any and all input.

 

 

[overtone]

Allow more progeny per reproductive event, or more reproductive events per lifespan, and the odds (of transmission at least) get much better than 50/50.

 

Also: parthenogenesis, fission (check out Volvox), different styles of parenting, symbiosis, etc, change those odds.

Edited June 7, 2013 by overtone