Entity Documentation - minecraft:genetics

Defines the way a mob's genes and alleles are passed on to its offspring, and how those traits manifest in the child. Compatible parent genes are crossed together, the alleles are handed down from the parents to the child, and any matching genetic variants fire off JSON events to modify the child and express the traits.

Genetics Properties

Name	Default Value	Type	Description	Example Values
genes	not set	Array of Genes items	The list of genes that this entity has and will cross with a partner during breeding.	Goat: [{"name":"goat_variant","use_simplified_breeding":true,"allele_range":{"range_min":1,"range_max":100},"genetic_variants":[{"main_allele":{"range_min":1,"range_max":2},"birth_event":{"event":"minecraft:born_screamer","target":"self"}},{"main_allele":{"range_min":3,"range_max":100},"birth_event":{"event":"minecraft:born_default","target":"self"}}]}]
mutation_rate	0.03125	Decimal number	Chance that an allele will be replaced with a random one instead of the parent's allele during birth.	Goat: 0.02

Genes

The list of genes that this entity has and will cross with a partner during breeding.

Genes Properties

Name	Default Value	Type	Description	Example Values
allele_range	not set	Integer number	The range of positive integer allele values for this gene. Spawned mobs will have a random number in this range assigned to them. Can be a single integer or an object with range_min and range_max properties.
allele_range (Alternate 1)	not set	Allele Range item
genetic_variants	not set	Array of Genetic Variants items	The list of genetic variants for this gene. These check for particular allele combinations and fire events when all of them are satisfied.
mutation_rate	-1	Decimal number	If this value is non-negative, overrides the chance for this gene that an allele will be replaced with a random one instead of the parent's allele during birth. Non-negative values greater than 1 will be the same as the value 1.
name	not set	String	The name of the gene.
use_simplified_breeding	not set	Boolean true/false	If true, mobs spawned from breeding will always inherit main alleles from parents' main alleles and hidden alleles from the hidden ones.

Allele Range

Allele Range Properties

Name	Default Value	Type	Description	Example Values
range_max	not set	Integer number	Maximum allele value
range_min	not set	Integer number	Minimum allele value

Genetic Variants

The list of genetic variants for this gene. These check for particular allele combinations and fire events when all of them are satisfied.

Genetic Variants Properties

Name	Default Value	Type	Description	Example Values
birth_event	not set	Minecraft Event Trigger	Event to run when this mob is created and matches the allele conditions.
both_allele	-1	Integer number	If this value is non-negative, compare both the mob's main and hidden alleles with this value for a match with both. Can also be a range of integers.
both_allele (Alternate 1)	not set	Both Allele item
either_allele	-1	Integer number	If this value is non-negative, compare both the mob's main and hidden alleles with this value for a match with either. Can also be a range of integers.
either_allele (Alternate 1)	not set	Either Allele item
hidden_allele	-1	Integer number	If this value is non-negative, compare the mob's hidden allele with this value for a match. Can also be a range of integers.
hidden_allele (Alternate 1)	not set	Hidden Allele item
main_allele	-1	Integer number	If this value is non-negative, compare the mob's main allele with this value for a match. Can also be a range of integers.
main_allele (Alternate 1)	not set	Main Allele item

Both Allele

Both Allele Properties

Name	Default Value	Type	Description	Example Values
range_max	not set	Integer number	Maximum allele value
range_min	not set	Integer number	Minimum allele value

Either Allele

Either Allele Properties

Name	Default Value	Type	Description	Example Values
range_max	not set	Integer number	Maximum allele value
range_min	not set	Integer number	Minimum allele value

Hidden Allele

Hidden Allele Properties

Name	Default Value	Type	Description	Example Values
range_max	not set	Integer number	Maximum allele value
range_min	not set	Integer number	Minimum allele value

Main Allele

Main Allele Properties

Name	Default Value	Type	Description	Example Values
range_max	not set	Integer number	Maximum allele value
range_min	not set	Integer number	Minimum allele value

Samples

Goat

"minecraft:genetics": {
  "mutation_rate": 0.02,
  "genes": [
    {
      "name": "goat_variant",
      "use_simplified_breeding": true,
      "allele_range": {
        "range_min": 1,
        "range_max": 100
      },
      "genetic_variants": [
        {
          "main_allele": {
            "range_min": 1,
            "range_max": 2
          },
          "birth_event": {
            "event": "minecraft:born_screamer",
            "target": "self"
          }
        },
        {
          "main_allele": {
            "range_min": 3,
            "range_max": 100
          },
          "birth_event": {
            "event": "minecraft:born_default",
            "target": "self"
          }
        }
      ]
    }
  ]
}