Genetics

For a full list of available genes, see Genes.

Genetics are a system introduced in the Biotech DLC, which can add new capabilities to your pawns.

Genes

Main article: Genes

Genes are the core feature of the genetics sytem. There are a wide variety of genes, each offering changes, minor or major, positive or negative. Each type of gene has 2 stats:

• Metabolic Efficiency - determines how much food they will need to eat. Otherwise negative genes will increase efficiency (lowering hunger), while otherwise positive genes decrease efficiency (thus, increasing hunger). There is a hard limit of -5 Metabolic Efficiency (x225% hunger). It has no effect past +5 (50% hunger).
• Complexity - determines how hard it is to create an implantable xenogerm of that gene. A xenogerm with more and more complex genes will require more gene processors and will take longer at a gene assembler to create.

Certain genes are Archite genes. These genes provide extremely powerful effects, and require archite capsules to install into your colonists. They cannot be extracted with a gene extractor.

Heritability

There are 2 forms of genes that a pawn can exhibit. For any specific gene, a pawn will exhibit either the germline or xenogene version:

• Germline genes (also called Endogenes in the code) are genes heritable through birth. They cannot be modified in any way. However, if a germline gene and xenogene would conflict, the xenogene takes priority.
• Xenogenes are genes modified during life, and cannot be inherited through birth. A xenogerm can be used to add xenogenes to any pawn. Specifically, a xenogerm will overwrite all xenogenes and replace them with its own. Xenogenes also count as artificial enhancements for body modders and body purists, as well as transhumanist and flesh purity ideoligions.

There is no other functional difference between germline genes and xenogenes, and both can be extracted (unless they are Archite genes). Certain xenotypes that have naturally adapted to their environment, like impids and yttakin, use germline genes. Other xenotypes that have been designed, like genies and highmates, use xenogenes.

Genes can be stored in item form as genepacks. Genepacks themselves must be stored in a powered gene bank, or they will slowly deteriorate.

Overview

How to edit genes

There are 3 steps to gene modding within your colony:

1. Research Xenogenetics. This project is available as soon as you research Electricity.
2. Gather desirable genepacks, either from a gene extractor or through trade. Store them in a gene bank.
3. Use a gene assembler to create a xenogerm. This xenogerm can be implanted into your colonists to give them genes.

Further research is required to create more complex xenogerms and use the Archite genes.

Xenotypes

Main article: Xenotypes

The game's 11 default xenotypes will appear throughout the game, and in various factions. Each xenotype comes with their own set of genes to take advantage of, without having to go through the whole gene modding process. In order to use the gene extractor, you'll need pawns of different types to extract from.

You can also have your starting colonists be of a custom, player-defined xenotype. You can freely and fully customize your own xenotype. If you started the game with a player xenotype, or if an ideoligion references a xenotype, then they'll very rarely appear throughout the world.

Obtaining genepacks

Genepacks can be obtained by using a gene extractor, through trade, or as a quest reward. In any case, you'll need a gene bank to store gene packs, or they will deteriorate soon enough. Genepacks are not consumed; so long as they aren't destroyed, you can use their genes forever.

• Gene extractor

The gene extractor will extract a random genepack from a pawn, whether they are a colonist, prisoner, or slave. Each extraction has a 70% chance of extracting 1 gene, 20% chance of extracting 2 genes, and 10% chance of extracting 3 or 4. In any case, all genes will be stored in a single pack; you cannot separate the genes inside. Which genes you get are entirely random, but 0 Complexity genes (cosmetic genes like Pig Ears) are 33% as likely to be obtained.

Extracting a genepack causes the Genes Regrowing condition for 12 - 20 days. This prevents future extraction, unless you want to kill the pawn. In addition, gene extraction causes Gene Shock for 2 days, with mild symptoms (+5% pain, −5% Consciousness, −15% blood filtration).

The extractor can extract both xenogenes and germline genes. However, it cannot extract any of the Archite genes.

• Trade / Quests

Genespacks can be sold by exotic goods traders or faction bases, of the outlander tech level or higher. They can also be offered as a quest reward.

These are the only way to get Archite genepacks. Archite genes will always come with at least 1 other gene; you cannot get an isolated archite gene normally.

Assembling a xenogerm

Xenogerms can be created with the help of gene assemblers, and if needed, gene processors.

• Gene assembly

Gene assemblers create xenogerms, using any gene found in nearby gene banks. Once you have created a desired set of genes, then hit Start Combining. Assembling a xenogerm does not consume the genepacks.

By default, xenogerms cost no material to create. They only take colonist time. Pawns with higher Research Speed - namely those with high Intetellectual skill - will create xenogerms faster. Archite genes will require archite capsules per xenogerm.

In order to create genes with a Complexity over 6, you will need a gene processor. Each processor costs  100 Steel,  25 Plasteel,  2 Components and increases the complexity limit by +2. In order to build gene processors, you'll need the Gene Processor research.

• Installing a xenogerm

Once a xenogerm has been created, all you need to do is install it. This can be done by selecting the xenogerm and using the Order Implantation gizmo. You can also order implantation by selecting it as an operation. Implanting a xenogerm costs 4 herbal medicine or better, and causes a xenogerm coma for 1-3 days. The exact time of the coma depends on the quality of the surgery (see Breakdown of Xenogermination Time for details).

Analysis

Gene modding

For being an advanced technology on Earth and in other fictional media, gene modding in RimWorld is quite inexpensive:

•  200 Steel,  8 Components for a gene extractor
•  200 Steel,  4 Components for a gene assembler
•  50 Steel,  1 Component per gene bank, which stores 4 genepacks per bank
• 4 herbal medicine per xenogerm implantation, and nothing to create one

You don't need to build the assembler until you actually have genes you want to implant. Therefore, the total cost to start the gene process is only  250 steel and  9 components, a very affordable cost.

However, getting your desired genes is another story. Extractors take a long time, especially if you want a specific gene. Each extraction takes 12-20 days per person, for entirely random genes; there's no protection against duplicates, for instance. If you want to experiment with gene modding, it's best to start early. Plan ahead, capturing many prisoners of a desired xenotypes, even if you don't want to recruit them. Give any gene-donors the leg treatment to make sure they don't rebel. You can also use gene-donors for their blood and a lung, if so desired (removing a kidney makes them vulnerable to disease). Traders and quests offer genepacks purely through the whims of RNG.

Power costs are minimal. Each gene bank consumes -40 W of power. Both the extractor and assembler can be turned off when they aren't needed, and in any case, have a total power draw of only 300 W.

The benefit
In return, genes can be well worth it. For example:

• Neanderthals - Robust is ×75% damage from all sources, stacking with the tough trait. This equates to ×133% more health in just about every combat situation. Enough to prevent a short bow from instantly killing your pawns through a headshot.
• Genies - Great Creating means +8 Crafting skill. You still learn and lose the skill at the normal rate, just that you have an additional +8 skill. Level 20 Crafting is both easy to reach and keep - with a "natural" level 20 pawn, their skill XP will decay quickly. This applies to every Strong/Great <skill> gene out there.
• Wasters - Psychite dependency means that your pawns can take flake or yayo, instantly gaining +35 mood any time, without addiction or any possible overdoses. Metabolic efficiency increases by +4, reducing hunger to ×60% or allowing you to install other genes. (You can still get kidney damage if tolerance is too high).

All "dependency" means is that you need 12 flake/psychite tea per year. Even with the reduced plant yield from Losing is Fun, only 10 psychoid plants are enough to sustain a dependent pawn for an entire year.

• Sanguophages - While you can't just extract their Archite genes, sanguophages come with a large variety of good and bad genes. From Low Sleep to Fast runner to Robust to any of the Hemogenic genes, you can get a lot. Capture all the sanguophages in the sanguophage gathering quest, and get a chance at a large variety of genes - and 2 lungs, 2 kidneys, a heart, and a liver per prisoner. Note that sanguophages often have the Genes Regrowing hediff from the start, unless you select "Xenogerm implantation" as a reward.

Of course, these are not the only great genes out there. Virtually every xenotype has at least 1 gene worth extracting.

With any extracted gene, they are independent from any of the pre-existing xenotypes. Instead of being stuck with a neanderthal's Slow study and Slow walker, you can choose your own downsides for your Robust xenogerm (so long as you actually have the genepacks to do so).

Even if you started with your own xenotype, any recruited colonist will most likely not be that xenotype. It takes an extremely long time to replicate a player's xenotype exactly, but you can give new pawns a bunch of great genes in the process.

Version history

• Biotech DLC Release - Added.
• 1.4.3527 - Fix: Genetic metabolism doesn't actually effect hunger rate.
• 1.4.3529 - Fix: Some randomly chosen genes not overridden properly.
• 1.4.3555 - Xenogenes count as artificial enhancements for body modders/prosthophobes.^[sic]
• 1.4.3557 - Fix: Inactive genes affecting needs.