Population modification

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This article is for the PC version of Stellaris only.

*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 with the  Clone Soldier or  Clone Soldier Ascendant traits cannot be genetically modified.

## Number of traits

### Trait Points

The number of traits of a species is limited by the total cost of those traits against **Trait Points**. The starting number of trait points is **2** for biological species, **1** for  machine species, and **0** for  robots. The cost of a trait can be negative, zero or positive.

Trait points can be gained from various sources, as listed below.

### Trait Picks

The number of traits of a species is limited by the **Trait Picks** limit. Initially, trait picks are limited to **5**, except for  robots which are limited to **4**. Traits which cost **0** points do not count against the number of trait picks.

Trait picks are increased by Ascension Paths, the  Mechanist origin, or hybrid species as listed below.

## Species templates

Population modification is done via **templates**, which creates a subspecies. Templates can be applied to pops per subspecies (including original species), per planet, or per subspecies on a planet. 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, templates with at least one pop cannot be changed directly and the template modification window presents only the option to create a new one.

After a template has been applied, a special project to modify the selected pops appears in the situation log. The project timeouts in 30 days if not started. Depending on the type 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.

The cost to modify a species can be reduced by **−50%** by the following traditions:  Prefabricated Components,  Modular Cybernetics, or  Retroviral Manipulation. Additionally, the  *Plentiful Fossils* archaeology site can add a permanent **−25%** modification cost.

 Advanced modification
* Genetic Resequencing tradition: Remove positive or Overtuned traits, add negative or advanced traits
* Overtuned origin: Add or remove Overtuned traits
* Integrated Anatomy tradition: Add or remove cybernetic traits
 Cost
* **+5** per affected Pop
* **+20** per affected Pop per absolute Trait Point difference between the old and new templates
* **+60** per affected Pop if climate preference is changed
* **+20** per affected Pop
 Trait points
* **Targeted Gene Expressions** technology: **+1**
* The Omnicodex relic: **+1**
* Genetic tradition tree (**+6** total):
	+ adoption: **+2**
	+ Engineered Genesis tradition: **+2**
	+ finisher: **+2**
* Modular Cybernetics tradition adds robot trait points for organic species:
	+ Machine Template System technology: **+2**
	+ Cross-Model Standardization technology: **+1**
	+ **Fungible Circuitry** technology: **+1**
* Hybrid species: **+1**
* Under One Rule origin (**+2** total):
	+ Genome Artists leader trait: **+1**
	+ Genetic Perfection leader trait: **+1**
* Cross-Model Standardization / Binary Motivators technology: **+1**
* **Fungible Circuitry** / **Nanite Assemblers** technology: **+1**
 Trait picks
	+ Integrated Anatomy tradition: **+1**
	+ finisher: **+1**
* Allelic Expression tradition: **+1**
* Hybrid species: **+1**
* Composer of Strands covenant (starting): **−1**
* Composer of Strands covenant (upgraded): **−2**
* Synthetic tradition tree finisher for  robots: **+1**
* Efficient Power Systems tradition for  machine species: **+1**

## Uplifting

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 instantly integrates the uplifted species and gains  50 Influence. In addition, the uplifted species gains  **+10%** Happiness when living within the borders of the empire that uplifted it. The initial ethics of the uplifted species are determined by a series of initial events. 100% Afterwards, the species is fully susceptible to ethics divergence.

## Ascension paths

Population modification can be used in conjunction with some of the ascension tradition trees.

* The  Genetic tradition tree focuses entirely on genetic modification. This tradition tree grants additional trait points and trait picks, unlocks new, more powerful traits and grants more freedom when it comes to adding and removing traits.
* The  Cybernetic tradition tree enhances all empire species with the  Cybernetic trait and eventually unlocks cybernetic traits, which are similar to robotic traits, cheaper, but with an additional energy upkeep.
* The  Psionic tradition tree adds the  Psionic trait, which cannot be acquired or removed through genetic modification. At first, only the founding species gains it, but other species living in the empire can gain it through  assimilation.
* The  Synthetic tradition tree focuses on robomodding and eventually replaces genetic modification with robomodding entirely.

## Hybrid species

 Xenophile empires can pick the  Xeno-Compatibility Ascension Perk to allow the reproduction of two organic species into a 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** trait point and **+1** trait pick. Two species are 3× more likely to create a hybrid species if they are part of the same species group.

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

## References

1. ↑ A template may be deleted automatically if there are zero pops with it after a modification project

**Game concepts**