Breeder's Guidebook - sekelsta/horse-colors GitHub Wiki
Right click on a horse with a book to get a breeder's guidebook. When you open it, there will be information about the horse's stats, speed, health, and jump. This is in the "physical inspection" section, and it's not perfectly accurate but more what you would see from looking at the horse. There will also be genetic test results for its colors. This is the "genetic tests" section, and it only includes what there is a test for in real life.
Stats
Information about the health, speed, and jumping stats is found in the "physical inspection" section. From best to worst, most of the stats are described as "excellent", "good", "average", "poor", or "abysmal". Immune system health is different because it depends on genetic diversity, from best to worst it can be "diverse", "mediocre", "inbred", or "extremely inbred". Diverse includes both excellent diversity and good diversity.
Colors
Genetic test results for the color genes are found in the "genetic tests" section.
Note: This page is a bit old and a couple more color genes have been added since.
Using horse simulator
You can use this interactive website to find out more about what your horse's color genetics mean. To translate, look at your horse's gene book line by line. For each gene, it will list the name and which two alleles your horse has.
The gene book sometimes includes a "+", which in biology is often the symbol used for the wild type. It generally means whichever option is older / more common / more boring.
Extension
This one is really simple, E means E and e means e.
Agouti
An "A" in the gene book means an "A" in the horse simulator, and an "a" in the gene book means an "a" in the horse simulator. The horse simulator also includes the hypothesized alleles "A+" and "At". Genetic tests for horses thought to have those alleles will show "A", so that is what the gene book shows as well.
Dun
The gene book can show three options for dun, "D" (dun), "nd1" (non-dun 1), and "nd2" (non-dun 2). In the horse simulator there are only two options, "D" which is equivalent to "D", and "d" which is equivalent to "nd2". Non-dun 1 would look similar to non-dun 2 but with the stripe down the back that dun has.
Gray
Gray is again simple, "G" means "G" and "g" means "g".
Cream
Cream can be "Cr" for cream, "prl" for pearl, "sn" for snowdrop, or "+" for the wild type (non-cream). In the horse simulator, "Cr" is "Cr", "prl" is "prl", "+" is "cr", and "sn" is too new.
Silver dapple
Silver dapple is again simple, "Z" means "Z" and "z" means "z".
KIT
The KIT gene in the horse book is split up in the horse simulator, into roan, sabino, dominant white, and tobiano.
- + - normal (wild type), in the horse simulator this is rn+, sb1+, w+, and to+ (all of them at the same time).
- To - tobiano, in the horse simulator this is "TO"
- Rn - roan, in the horse simulator this is "Rn"
- Sb1 - sabino 1, in the horse simulator this is also "Sb1"
- W - dominant white, in the horse simulator this is also "W"
- W20 - increases white markings, this does not exist in the horse simulator
- To+W20 - both tobiano and W20 combined on the same allele, this is also not in the horse simulator
Frame overo
For frame overo, "O" means "O", and "+" in the book means "o" in the simulator.
Splashed white
Splashed white can be on one of two genes, MITF or PAX3. In the horse simulator, there is only one splashed white and it is listed as "spl" or "SPL". In the mod, there is also only one splashed white so far and it is on MITf, so you can just think of MITF as being equivalent to splashed white. As usual "+" in the gene book means normal and it is the same as "spl" in the horse simulator, while "SW1" in the gene book is the same as "SPL" in the simulator.
Leopard complex
A "+" in the gene book is equivalent to "lp" in the simulator, and "Lp" in the gene book is equivalent to "Lp" in the simulator.
Pattern genes
For pattern 1, "+" in the gene book is equivalent to "patn1" in the horse simulator, and "PATN" in the gene book is equivalent to "PATN1" in the simulator. Note that although the simulator shows all horses with PATN/+ as being full leopards, that genotype can also produce semi-leopards and large blankets. Pattern 2 will not show up in the gene book as there is no test for it, also it is not thought to exist as shown in the simulator. (see Appaloosa Project - PATN2 is Not the Blanket Gene) There may eventually be a test for a gene which is named "pattern 2", but if there is it may act differently from the PATN2 in the horse simulator.
Flaxen and sooty
The horse simulator shows flaxen and sooty, however they still have unknown genetics that may not work like the horse simulator shows. They do not appear in the gene book as there is no test for them, if they exist at all.