Cell Reproduction

We will want to replace reproductase soon, and as was suggested before, the replacement would be a threshold level of ATP. However, the replication in cells should be a bit more complex than that (and also if we switch to having ATP being mostly maintained at a constant level that would mean you could replicate all the time).

Here’s my proposal for a system to replace reproductase (up for review).

This system basically has DNA synthesis, division of the nucleus, and division of the cell all happen in one step. There are several requirements for the cell to be able to replicate:

  • Compounds need to exist in a certain amount in the cell. This needs to be decided upon. It would be some combination of glucose, amino acids, etc. The absence of any one of these compounds would prevent replication, whereas a low amount of any one of these compounds just slows down the process.
  • ATP must be at its normal level. If we go with the system of ATP not being gained over time but rather maintained at a certain level, then you would just have to ensure your ATP is at this level to be able to replicate.
  • The nucleus must be free of damage. If any damage has been done to the nucleus (and thus implicitly, to the DNA), then replication is locked until the nucleus has been healed. We can also decide whether other organelles must be fully healed as well.


  • The cell must be at a threshold size. This doesn’t apply now but will apply when we have dynamic membranes.

When all of these conditions have been met, the player can reproduce.

By looking at this you might think that it overcomplicates reproduction for the player, but from the player’s end, there’s not much that they need to know. Provided their cell is undamaged and ATP levels are normal (ATP levels should only ever not be normal when the cell is not undamaged anyways) then the player just has to go out and gather some compounds until they can reproduce.

This ensures a gameplay cycle of:
Spawn->Gather Compounds->Reproduce->Evolve in the Editor->Repeat

What this leaves open to be decided is the specific compound levels necessary for reproduction, and whether organelles beside the nuclear core (nucleus, ER, golgi) should be undamaged before replication can occur. The required compound levels should scale somehow with the size of the cell and the organelles present in the cell. It could even scale based on how much the organelles in the cell have been upgraded, so that upgrading an organelle can increase it’s effectiveness, but as a consequence increase the requirements for reproduction. This would mean smaller cells with “simpler” organelles could reproduce far faster than a larger cell with highly upgraded organelles.


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This ties directly in with the locked vs free compounds stuff that’s part of the CPA system – from the blueprint of the cell we need to figure out how many compounds go into manufacturing a copy. Sadly, we never actually answered that question, I’m only pointing out that the question is the same.

I think organelle upgrade compound cost is a particularly tricky one – certain upgrades would reduce the compound cost of an organelle that has the same level of function, for example, while others might increase the size of an organelle to increase its effectiveness, thereby increasing compound cost. I think we’d have to set numbers, real numbers, using estimates of the dry-weight breakdowns of various organelles, and fudge the numbers one way or another from there.

We’d also have to improve the compound/process system so we get the whole self-regulating thing going, where ATP levels are regulated by making supply (through glycolysis and respiration) match demand, and where, say, proteins, lipids, and nucleotides/nucleic acids are constantly produced at a certain rate to feed growth, with additional production of those three to feed repairs.

Then, to decide if you are able to reproduce yet, you check if your stockpiles of those 3 compounds are at least double the minima, and if so, you can reproduce, and each daughter cell will have exactly half of everything.

Personally, I’m very partial to a more nuanced system: let the player reproduce even if they have, say, only 1.6x the minimum required protein, but each daughter cell would be starved for resources (ie, organelles would suffer scaled amounts of damage), and maybe they’d have a little penalty to mutation points to discourage gamey speedmutating, if we decide we want to do that. Obviously, we would have to make this clear in the interface – instead of having a simple progress bar, we’d have a progress bar with a marker sitting somewhere in the middle, to indicate when you can reproduce, and when you can do so healthily.

None of what I’m suggesting is new, honestly, I thought we already decided on all this a few months ago, but maybe you weren’t happy with the result so you’re opening discussion again :stuck_out_tongue_winking_eye:

Now, as specific responses to a few of your points:

  • threshold size: I assume this means by dry mass. By extension, I assume this would probably measure size as something like min(compound_x_amt/compound_x_min_amt_for_mitosis, …), which is exactly what I’m suggesting above (barring the nuance about being allowed to split too soon)
  • required compounds: also pretty much what I said above, together with threshold size
  • ATP at normal level: I like it. Maybe add the additional constraint that a certain amount of glycogen/other-sources-of-energy be available, since mitosis is not cheap.

With all of these requirements, we could probably have the UI be something like a simple progress bar with a little popup display on hover that summarizes requirements and shows which are met/unmet.

Maybe, in addition to all this, we could have each organelle (well, the ones where this makes sense at least) have a ‘size’ parameter that scales up as protein/lipids/nucleic acids get incorporated in them.

Oh shoot I forgot that discussion. If need be I could merge this thread into that one.

I think it was on Slack.

I think I found the one you’re referring to here actually: Microbe Stage GDD

It was based on what had been written in the GDD, which was mostly speculation at the time and probably needs refining: http://thrivegame.wikidot.com/gdd-microbe:gameplay#toc11

(A bit late with this response)

Since that was a general thread for the GDD, I’d suggest we keep this thread open for discussion specifically about reproduction.