Population modification

Version

This article is considered accurate for the current version (2.3) of the game.

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 types

Species types define the trait types a species can have, the type of possible population modification, the way they unlock additional Trait Points and how their rights are determined.

Type	Required Trait	Modification type	Initial Trait Points	Rights
Biological	None	Genetic modification	2	Determined by Species Rights
Robotic	Mechanical	Robomodding	0	Determined by Artificial Intelligence Policy
Machine	Machine	Robomodding	1	Determined by Species Rights
Pre-sapient	Any pre-sapient trait	Uplifting	1	Determined by Pre-Sapients Policy

Trait points and Picks

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 during on 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

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. As such any change to the species rights of a template will be applied to the entire species, not just the template.

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 Modification	Robomodding
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 Hybrid species have one additional trait point and one additional trait pick	Cross-Model Standardization / Binary Motivators technology grants +1 Fungible Circuitry / Nanite Assemblers technology grants +1 Machine Template System technology grants +1 Synthetic Evolution ascension perk grants +1 Synthetic Age ascension perk grants +2

Uplifting

For pre-sapient species the option to create templates is replaced with the option to uplift and bring them to sapience. Uplifting a species has some advantages over conquering another species or other forms of genetic engineering.

Rules:

• Uplifting requires the Epigenetic Triggers technology, and costs 3000 Society research.
• Upon completion, the uplifted species is immediately integrated into the empire which uplifted it, and the homeworld is added to the empire as a free colony. Additionally, the empire will gain 500 Influence.
• All uplifted species have a special trait that cannot be acquired during Empire creation or genetic modification. This trait will make them excel at some jobs far beyond what normal species can do, but often at the downside of making it unsuitable for other purposes.
• The species will naturally be thankful to the species that uplifted them and get +10% happiness via the free Uplifted Trait if staying in the same empire as their benefactors.
• The species will appear with Random Ethics. Several prompts give the uplifting Empire an opportunity to help decide the species' ethics to override the original setting for all pops. The species is fully susceptible to Ethics divergence.

Assimilation

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 up to 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 and Devouring Swarms 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	Requirements	Traits gained	Traits removed	New living standard
Identity Sublimation	Driven Assimilator	Cybernetic	Hive-Minded Self-Modified	Drone
Identity Sublimation	Evolutionary Mastery Hive Mind	Hive-Minded	Self-Modified	Drone
Transubstantiation Synthesis	The Flesh is Weak	Cybernetic	Hive-Minded Self-Modified	Full Citizenship
Transubstantiation Synthesis	Synthetic Evolution	Mechanical	All	Full Citizenship
Hive Dissociation	Evolutionary Mastery Hive-Minded species Gestalt Consciousness		Hive-Minded	Full Citizenship
Transcendent Awakening	Transcendence	Psionic	Latent Psionic	Full Citizenship

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

Ascension paths

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 robomodding. Cybernetic pops are prohibited to be assimilated, as Synthetic empires are always also a Cybernetic empire.

Hybrid species

Xenophile and Fanatic Xenophile empires that research the Gene Tailoring technology can pick the Xeno-Compatibility Ascension Perk to allow the reproduction of two 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.

A Caravan event unique to Xenophile and Fanatic Xenophile empires also has a 33% chance of creating a hybrid species.

Genetic modification events

Aside from scheduled genetic modification species can also be spontaneously modified as a result of some events.

• After researching Gene Tailoring, if a colony in the empire has less than 40% Habitability and at least 4 primary species pops with under 50% happiness, the self-modification event chain will fire at some point within the next 200 months. Some of the pops on the planet will convert to a new subspecies with their primary habitat matching the planet they're on, the Self-Modified trait, and otherwise random traits. While the player cannot modify the self-modified subspecies template, they can still apply other templates to the self-modified pops and effectively undo the self-modification. The event will only take place once.
• One of the Horizon Signal events will issue a special project to investigate an escape pod. Not ending the event with any of the next two choices will result in the scientist unleashing a retroviral agent on the empire's planets. The option is given to either limit it to the homeworld or allow it to change the entire main species. The appearance of the modified pops will change, Militarist and Fanatic Militarist empires pops will gain the Intelligent trait and become pacifist, and non-militarist empire pops will gain the Resilient trait and become militarist. Only Authoritarian and Fanatic Authoritarian empires can prevent the change by purging all but one pop from the homeworld.
• Finishing the Horizon Signal and accepting the Worm's offer will give all Pops in the home system the Natural Physicists and Repugnant traits and the Tomb World Climate Preference.
• One of the anomaly events will find a high-speed box orbiting the planet. Any choice except ignoring or selling it will end with opening the box and using one of the substances to instantly enhance the main species with the following trait:
  • Red solution grants Social Pheromones
  • Green solution grants Bioadaptability
  • Blue solution grants Limited Regeneration

• Forming a Covenant with the Composer of Strands in the Shroud will mutate every Psionic species in the empire roughly every 25 years, changing traits completely at random.

• If an empire is no more than 3 hyperlane jumps away from Chor's Compass there is a very small yearly chance that pops on a planet will gain the Resilient trait.

• One of the anomaly events will give the option to start a Neural Symbiont Special Project if not Machine Intelligence. Finishing it will give the option to allow a scientist leader to become a host for a neural slug. If allowed a month later the option to bond the population of the capital with the slugs become available. Agreeing will give 3 Pops on the capital the Brain Slug Host trait.

References

Game concepts