ACNH/ACNL Advanced Flower Genetics
By Paleh (Re-formatted by DrDrub)
<aside> 💡 Update: Thanks to recent data mining from Aeter (Aeter#9823 on Discord), we now know the genes of all the New Horizon flower species! Huge thanks for getting this info! This guide has been updated with all the new gene data for all species.
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Animal Crossing New Leaf and New Horizons both use a surprisingly complex genetics system. Every flower has its own unique genes it carries, and you cannot always tell what recessive genes a flower carries based solely on its color. The system uses basic Mendelian genetics, the same system that’s normally taught in school. Since it’s Mendelian genetics, you can also make use of punnett squares to predict offspring.
The gene system is able to record up to 4 different genes for each flower, however some species use less than 4. The majority of the species in New Leaf use only 3 genes, with roses using 4 and carnations using 2. It's currently unknown how many genes the New Horizon-only species use.
Flowers from seed bags always have the same genes, so these are vital for being able to predict what offspring you’ll get.
In New Leaf, both flowers found on Island tours, as well as flowers planted by villagers, have the same genes as the seed bag flowers and can be safely used for breeding.
In New Horizons, hybrids found on mystery islands have different genes than those you would normally get by breeding the seed bag parents. Often these flowers have the genes necessary to produce third/fourth generation hybrids (e.g. blue roses, purple windflowers, etc.). Base color flowers on mystery islands always have the same genes as seed bag flowers.
<aside> 💡 Disclaimer: The genes are not labeled in the game’s programming, they’re simply represented by numbers in-game. The labeling here is simply to make it easier to read and understand for players. The game itself only uses binary and 0-2 numbers in the source code. All names and definitions are a matter of interpretation, check the technical explanation section for details on exact implementation.
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While four genes exist, only roses use all four. This section will talk about the gene’s general purpose mainly as it applies to roses, but the genes have similar or identical purposes on other species.
The actual displayed color of the flower is based on genes, but when you get to later generations with all of the genes interacting, it’s not always easy to predict which genes will cause which color due to complex gene dominance rules.
If you’re curious what color each gene combination is associated with, there’s a spreadsheet below with the flag values and colors. This can be helpful to look through if you’re trying to make complex breeding plans.
Despite the unpredictability of some gene combinations, there does seem to be a pattern on what each gene does to a flower.