Population modification

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This article is for the PC version of Stellaris only.

Every species can be radically changed through genetic or cybernetic modification

See also: Traits

Population modification refers to the process of altering a population's traits either to change its habitability, create subspecies suited for different tasks or improving it after unlocking more trait points through research. Both organic and robotic pops can be modified and each has its own set of traits. In addition, a small number of events can modify the population of a colony.

Species archetypes[edit]

Species classes are further grouped by species archetypes. Each of them can have different mechanics and even available traits.

Species archetype	Trait	Upkeep resource	Multiplication	Modification	Additional mechanics
Biological		Food	Growth	Genetic	Can create hybrid species with all biological groups
Lithoid	Lithoid	Minerals	Growth	Genetic	Can use some natural resource traits Can use the Calamitous Birth origin
Machine	Machine Unit	Energy	Assembly	Cybernetic	Must use Machine Intelligence authority
Robotic	Mechanical	Energy	Assembly	Cybernetic	Unlocked through Robotic Workers technology
Pre-Sapient	Any pre-sapient trait	None	Cannot multiply	Uplifting	Does not wear clothes

When it refers to Robotic, it's usually refering to both Mechanical species and Machine Unit species, not just the former.

When it refers to Biological, it's usually refering to only Biological species, except for Bio-Trophy and Biological Ascension Path being shared between Biological and Lithoid species.

When it refers to Organic, it's usually refering to both Biological species and Lithoid species.

Trait points and Picks[edit]

The two primary limiters to how many traits in what combination one can have are the Trait Points and Trait Picks. The first contact with both is on the species creation screen. Various technologies add additional Trait Points but Trait Picks are always capped at 5, except for hybrid species which have 6. In Utopia traits given by ascension paths do not count towards either limit.

Species templates[edit]

The genetic modification menu.

Population modification is done via templates. Templates can be applied to pops residing on a planet or to the entire species, previously modified or not. Modified pops are considered part of the same species as the original even if the name and portraits have been changed. However, it is possible to set different rights for templates and its parent species.

Templates with zero current pops can be freely modified or deleted however the ones with at least one pop cannot be changed and the template modification window presents only the option to create a new one.

After a template has been applied a special project to start modifying the selected pops will appear in the situation log. The project will timeout in 30 days if not started. Depending on the kind of modification, how severe the modification (total amount of trait point differences) and how many pops were picked, this special project can be very expensive in science. The system is currently designed towards favoring bulk modification of many traits over specific via a high base cost.

Type	Genetic	Cybernetic
Unlocked by	Glandular Acclimation for climate preference Gene Tailoring for adding positive and removing negative traits Genetic Resequencing for removing positive and adding negative traits	Machine Template System
Cost	3000 Society Research +5 per affected Pop +20 per affected Pop per Trait Point Difference between the old and new Templates +60 per affected Pop if climate preference is changed -25% for Engineered Evolution ascension perk -25% for Evolutionary Mastery ascension perk	1500 Engineering Research +20 per affected Pop +40 per affected Pop per Trait Point Difference between the old and new Templates -33% for Synthetic Age ascension perk -50% for Synthetic Evolution ascension perk
Trait Points	Gene Tailoring technology grants +1 Targeted Gene Expressions technology grants +1 Engineered Evolution ascension perk grants +3 Evolutionary Mastery ascension perk grants +3 The Omnicodex relic grants +1 Hybrid species have one additional trait point and one additional trait pick	Machine Template System technology grants +2 (+1 for machine empires) Cross-Model Standardization / Binary Motivators technology grants +1 Fungible Circuitry / Nanite Assemblers technology grants +1 Synthetic Evolution ascension perk grants +1 Synthetic Age ascension perk grants +2

Uplifting[edit]

For pre-sapient species the option to create templates is replaced with the option to uplift and bring them to sapience. It requires the Epigenetic Triggers technology and costs 3000 Society research. Upon completion the empire will instantly integrate the uplifted species and gain 500 Influence. In addition the uplifted species will gain +10% Happiness when living within the borders of the empire that uplifted it. The initial ethics of the uplifted species will be determined by a series of initial events although afterwards the species fully susceptible to Ethics divergence.

Assimilation[edit]

This special Citizenship with associated Living Standards allows the conversion of pops to better fit the existing empire, without the hassle of regular modification. Each year 3, 6 or 12 pops will be assimilated, chosen from among all assimilating pops. The type of assimilation depends on the empire and the pop in question.

Fanatic Purifiers, Devouring Swarms and Terravores can't perform any kind of assimilation. Hive-Minded pops can't be assimilated into an empire that isn't a Hive Mind, except with Hive Dissociation.

Assimilation type	Empire requirements	Species requirements	Traits gained	Traits removed
Identity Sublimation	Driven Assimilator	Organic species Cybernetic	Cybernetic	Hive-Minded Self-Modified
Identity Sublimation	Evolutionary Mastery Hive Mind	Organic species Hive-Minded	Hive-Minded	Self-Modified
Transubstantiation Synthesis	The Flesh is Weak	Organic species Cybernetic Hive-Minded	Cybernetic	Self-Modified
Transubstantiation Synthesis	Synthetic Evolution	Organic species Hive-Minded	Mechanical	All
Hive Dissociation	Evolutionary Mastery Gestalt Consciousness	Hive-Minded		Hive-Minded
Transcendent Awakening	Transcendence	Organic species Cybernetic	Psionic	Latent Psionic

Assimilating a pop from an invaded primitive species into a Gestalt Consciousness will additionally remove culture shock modifiers.

Ascension paths[edit]

Genetic modification can be used in conjunction with some of the ascension perks.

The biological ascension path focuses entirely on genetic modification. Each of the two ascension perks grants 3 additional trait points and reduces the cost of genetic modification projects by 25% as well as unlocking early the Gene Seed Purification and Genetic Resequencing technologies respectively.
The psionic ascension path adds the Psionic trait that cannot be acquired or removed through genetic modification. At first, only the founding species will get it, but other species living in the empire can get it through the aforementioned assimilation.
Choosing the synthetic ascension path will first enhance the empire's every species with the Cybernetic trait. Cybernetic species are still organic enough to be genetically modified. Finishing the synthetic ascension path will upload all Cybernetic pops into Robotic bodies, replacing genetic modification with cybernetic.

Hybrid species[edit]

Xenophile empires can pick the Xeno-Compatibility Ascension Perk to allow the reproduction of two organic species into hybrid species. Hybrid species take a portrait from one of the parent species and a mix of traits from both parent species, with at least one trait being inherited from each. They also get 1 additional trait point and trait pick. Two species are three times more likely to create a hybrid species if they are part of the same species group.