Rimworld Biotech Gene Inheritance

A guide on how gene inheritance works.

Testing done in dev. mode. No code was viewed.

Basic Information

There are three types of genes.

• Germline genes - your all natural home grown inheritable genes.
  
• Xenogenes - your lab created and injected genes.
  
• Archite genes - special high tech genes that are very powerful.

There are 3 numbers attributed to a gene.

• Complexity - a value that affects how many genes can be assembled into a gene injector.
  
• Metabolic Efficiency(ME) - increases/decreases hunger rate for pawns. (Abbreviated as ME here)
  
• Archite Capsules - a rare resource needed for implantation. Get from traders or quests.

Genes considered beneficial will usually reduce ME, increasing hunger rate. While genes considered detrimental will increase ME, reducing hunger rate. Archite genes will have high complexity with 0 ME change. The exception being Archite Metabolism, this gives +6 ME at the cost of 3 Archite Capsules.

Gene Inheritance

This section is about putting the genes you want on your pawns whether pureblood or hybrid.
Testing for this section was done using 'Extract ovum for IVF' operation, NOT pregnancy.

You can check the gene inheritance of a harvested ovum after it has been fertilized. It will show all potential genes it has inherited.

A germline gene is inherited if:

• Both parents have the gene. (guaranteed)
  
• One parent has the gene. (not gauranteed, reddit comments estimate 25% chance)

If there are multiple genes for skin tone/hair color etc, one will be picked after gestation. The unchosen options will be grayed out, yet still inheritable for future generations. Sometimes an unseen color gene is created after gestation. Currently unsure if it's due to me using dev. mode to add color genes or just random chance.

If two pawns of the same xenotype create a child together, the child will inherit the xenotype of the parents. If the parents do NOT share the same xenotype, the child will be a hybrid.


(There was apparently an issue with gene inheritance related to the order of genes and their ME values not allowing them to be inherited, even as a pureblood xenotype. This was related to how the algorithm rolled numbers for the new pawns total allowed -ME score and genes were ignored. The new 1.4 content update from 11-21-22 should have fixed/loosened these restrictions.)

Gene Implanter

The Gene Implanter gene is an Archite gene that injects all of a pawns genes into another pawn. There is some variability to its function.

What will get transferred:

• Xenotype - The pawns Xenotype will now read as the source pawns Xenotype.
  
• Germline genes - the new genes will take priority and null out and opposite/conflicting new genes from the previous Xenotype of the destination pawn.
  
• Xenogenes - same as Germline genes but will take priority over Germline genes.
  
• Archite genes - will get transferred ONLY if under the Xenogene category. If an Archite gene is in the Germline genes category, will NOT get transferred.

Could be used for custom Sanguophage playthroughs where one propagates genes to the others and only the original has the power of bestowal. (Put Gene Implanter as a germline gene, labeled as an endogene in dev. mode)

Does not appear to need archite capsules to transfer Archite genes.

Vat Grown, IVF, Natural Pregnancy

I have only experimented in dev. mode using IVF ovums with growth vats. I have not tested if everything works the same using natural pregnancies. It is possible the rates of inheriting a parents genes are different when carried to term by a parent but I doubt it really matters currently.

Testing Methods

I used dev. mode.

Removing the Hediffs that appear to prevent immediate gene implantation, ovum extraction etc. Leaving anesthetic on prevents subject from wandering off, thus speeding up the process.

Used pawns with correct gene sets to fertilize ovums. Sample size of ovums for each conclusion is 10.

It is possible for my data size to be too small, but it should be reliable enough since this is just a game. Now we can add eugenics to the list of Rimworld memes.(warcrimes?)

[D Dog]

Oh nice Mlie picked that up. I was looking at that back in July but it looked unstable based on comments. The new Mlie edit from August appears to not have many complaints. It also seems to provide features like cloning that aren't in Biotech. Genetics however doesn't appear to be a thing? Just copy-pasting personalities. Still a potential add but not really a replacement.

[SpaceRat]

You should just use Questionable Ethics mod. It's way better.

[Nameless King Faraam]

i also don't think it's useing a full punnet square system, but they may of done their precentiles based off a punnet squares precentiles, atleast for the first generation, bugger anything beyond that, in a traditional game the chances of your baby growing old enough to have kids of his own, are slim to nill i think

[D Dog]

I am under the impression it does not use a punnet square system due to no recessive modifier. Even if having the gene counted as dominant and not having it would be recessive, with a DD, Dr, Dr, rr outcome, the Dr would result as having the gene pass down. Pawns didn't seem to inherit 75% of genes, they seems to inherit only a few. It is possible since I didn't run a high density test with like a thousand trials, but I don't see any reason to math it using punnet squares with no dominant recessive system in place.

[Nameless King Faraam]

the 25% chance would be pretty accurate going off punnet squares, as there is a 25% chance for it to be dominant or recessive on the parent side, the question is if the game keeps that in mind for the next generation, i doubt it, but if it does i would be impressed