Barotrauma – Advanced Splicing: Comprehensive Guide on Genetics Mechanics

Barotrauma’s Genetics system is quite confusing and often misunderstood. This guide aims to explain all of the mechanics behind it, and help you make better use of your alien genetics.


This guide hopes to cover all the mechanics of the genetics system, however does not cover the gene effects themselves. Many debate over which are the best and worst, but this guide is not an opinion piece.

What will be covered here includes the obtaining and researching of Unidentified Genetic Material, the refining and combining of genetic material, and the usage in splicers. I aim to dispel some myths and common misconceptions, and overall inform on how to best make use of your genes.

Unidentified Genetic Material: Obtaining

Unidentified Genetic Material, (henceforth to be referred to as UGM) is the basic material of the genetics system, and to get the highest quality genes, you’re going to need a lot of it.

Obtaining UGM

UGM is most often looted from ruins and wrecks. There is a small chance to find some in a wreck or outpost’s medical cabinet, and a slightly higher chance to find them in incubation bubbles, which are found in ruins.

However, some jobs have talents that can increase the amount of UGM you find.

Gene harvester is the most notable talent, found in the Medic’s Scientist tree. It gives a 35% chance to find genetic materials on creatures that have been killed by you or another crewmember while outside the submarine.

The description is a little confusing, and there are some misconceptions surrounding how this talent actually works. When this talent is taken, if any crewmember is outside the sub and kills a creature, that creature will have a 35% to spawn UGM in its inventory. The item spawns upon death, and so it doesn’t matter who loots the creature. Anyone can kill the creature, and anyone can loot the creature. This talent stacks with multiple medics, as each medic with the talent has a 35% chance to add +1 UGM to the creature’s body. These chances are independent of each other, and so there is a chance to find multiple UGM on the same body, if you have multiple medics and are lucky enough. Note that since inventory spaces are somewhat limited on some creatures, not all creatures can drop UGM, since they do not have the space.

Creatures that can drop UGM:

  • Crawlers (max 1)
  • Husk Crawlers (max 2)
  • Tiger Threshers (max 1)
  • Bone Threshers (max 1)
  • Spinelings (max 1)
  • Giant Spinelings (max 2)
  • Molochs (all types) (max 1)
  • Humans (max 10) (includes crewmates)
  • Crawler Broodmother (max 1)
  • Hammerhead Matriarch (max 2)
  • Husks (max 5?)
  • Fractal Guardians (max 1)

All other creatures do not drop UGM.

Related to killing creatures, it is a misconception that the security officer’s Deep Sea Slayer Talent can cause creatures to drop UGM, due to it’s description: “When you kill a monster outside your submarine, it has a 40% chance of having additional alien material.”

However, the alien material that it is referring to are the alien metals; physicorium, incedium and such. Deep Sea Slayer does not cause enemies to drop more UGM.

There are two more talents that yield more UGM, and they are both related to spawning more items inside containers. The medic’s Researcher’s Intuition (1st talent left tree) and the security officer’s Scavenger (2nd talent left tree) both give a chance to spawn additional items in containers. When the effect is triggered (50% for Researcher’s Intuition, 20% for Scavenger), the loot will be re-generated, allowing more items to potentially spawn. This works well for medics opening incubation bubbles, which can appreciably increase UGM yield. Scavenger works on all containers, including incubation bubbles, but has a lower chance to trigger. It can, however, generate UGM in wreck and outpost containers, which Researcher’s Intuition cannot.

Both of these talents can be used on the same container, and by multiple crew with the same talent. It can occur once per character with one of the talents per container. It does not matter if the container is previously opened by another crew member without either talent.

Unidentified Genetic Material: Researching

So, you’ve gathered a bunch of UGM, what now? Well, here comes the fun part: using the Research Station to research your genes. This step will transform your useless genetic material into useful mutations that you can splice into people (though you might want to hold off until you get stronger genes.)

The process of researching UGM is very straightforward. You place one UGM into the Research Station with one Stabilozine, hit the button, and bam, you have genes. It doesn’t matter which item goes in which slot, just that both items are present.

You might have been worrying about having too low medical skill, and considered waiting until later to research your UGM for fear of tainting them. Well, fear not! When researching UGM, the product will never be tainted.

You may have noticed that your researched genes have some varying quality levels, and that is due to the way UGM is generated. While all UGM looks the same on the outside, the game considers them different, not just in the type of genes they research into, but also the quality.

There are 3 tiers of UGM. Tier 1 is the lowest quality, and most common, whereas tier 3 is the highest quality, and least common. Tier 1 UGM, when researched, will yield genes with quality somewhere randomly between 10-20%. Tier 2 will yield 20-40%, and tier 3 will yield 30-60%.

Now, it is impossible to know what tier your UGM is until you research it. All UGM items look the same and have the same name. Additionally, all types of genes are equally likely to spawn.

So, even though UGM is completely random, you at least now know how the mechanics work, and when you research UGM into some 60% quality genes, you’ll know that you’ve gotten very lucky.


Now, you’ve got a bunch of crappy genes, and want some powerful 100% quality before you go sticking them into people. This is where refining comes in.

The process of refining is similar to researching, however this time you will need two of the same type of genetics. By refining two genes together, you can create stronger genes.

While you can create stronger genes by refining, this step carries some risk. If your medical skill is low, you can taint your genes. Tainted genes have negative side effects when spliced, and cannot be further refined, and so you will likely be stuck with low-quality genes that have detrimental effects if used. You will know if your genes are tainted if the name changes to start with “Tainted”, like “Tainted Genetic Material (Husk)”. Pay attention to what you’re splicing into people, as you may end up with a nasty surprise if you don’t notice.

The two factors involved in taint chance are medical skill and gene quality. The higher your medical skill, the less likely to taint, and the higher quality genes you’re refining, the higher the taint chance. Note that the chance is only based on the quality of the highest quality gene. The chance will be the same if you have a 80% and a 10% compared to an 80% with an 80% (but you will see later why you shouldn’t put two 80% qualities together.)

The taint chance is displayed on the Research Station, so it’s up to you how much you’re willing to gamble. At around 200 medical skill, you should be able to refine anything with 0% taint chance.

(Note: At the time of writing this, there seems to be a bug in the displayed taint chance. You might notice that the chance changes if you switch genes between left and right slots. This is because it is doing calculation based on the item in the left slot, even if there is a higher percentage in the right slot. To be safe, put the genes with the higher quality in the left slot to see the true taint chance.)

A sensible question to ask might be: “How does the game calculate the strength of the new genes after I refine them?” Well, here’s how it works:

The game looks at the highest quality of the two genes you put in, adds 3-8% to it, and that’s your output. This may seem strange, but it really is that simple. What does this mean for you? Well, it means refining together two really high quality genes and hoping for a large quality increase is a really bad idea. There is no difference between refining an 80% gene with a 10% gene compared to a 50% one. They will both add 3-8%, and you will get a gene somewhere between 83-88% either way. So if you are combining together very high quality genes, it’s a bit of a waste. Combining one high-quality gene with one low-quality gene will get you the best results.

Now, it might take quite a while to get to 100% if you’re only adding 3-8% each time you refine, luckily the Gene Therapist talent makes refining a lot faster. The description says “Refining genetic materials adds an additional 10% potency.” And while this doesn’t seem like a major perk initially, compared to the base 3-8%, it is a very substantial effect. It will increase the range from 3-8% to 13-18%, which on average roughly triples the effect of each refine. This talent will seriously increase the amount of high-quality genes that you can produce, and while I don’t really like giving opinions in a guide like this, it’s seriously a much better choice than Dr. Submarine.


If you’re brave or foolish enough to try, it is possible to further enhance your genes: by combining different types together.

Combining works identically to refining, but instead of using two of the same genes, you combine two different types of genes together, with the full effects of both. However this carries a 100% taint chance, unless you have the Genetic Stability talent.

Even with Genetic Stability, the taint chance is still very high at 50%, so unless you’re willing to risk ruining those genes you worked so hard to refine, or are willing to put up with whatever side effects that come with it, it may be best to refrain from combining.

Also, it’s sometimes thought that Genetic Stability reduces refine taint chance, but it only reduces combine taint chance.


Splicing is when you put your genes inside a gene splicer, and use it on a person. There are two types of gene splicers, regular and advanced. Advanced splicers have two slots, and regular splicers have one. You should definitely aim to use the advanced splicer, and while it is a medic talent item, it can also be purchased at research outposts later in the campaign.

To use a splicer, place your genes into the splicer, then place the splicer into the slot in the health GUI (H) next to your head. It is impossible to splice genes into another person unwillingly, even if they are stunned or unconscious. The same goes for removing them.

Using an advanced splicer and combined genes, you can get up to four different gene effects at the same time. If both genes in an advanced splicer are tainted, then both taint effects will be applied.

You can remove your genes at any time, however you will lose them permanently if you do so. Previously it was possible to keep them by dying, however this no longer works.

Also, it is sometimes asked if genes stack. The answer is kinda. If you had 2 100% crawler genes, that wouldn’t be any better than 1 100% gene. However 2 50% genes would be equivalent to 1 100% gene. So genes stack, but not beyond 100%.

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