HGG Community Forums

What controls white factor?
White factor is a numeric representation of the the sum total of all the little things that influence the amount of white of a horse. Foals inherit some of their white factor level from their parents and some from the genes they have. Mutations can also push white factor up. The more mutations on a foal the higher it's white factor. Beware of breeding risky crosses when splash and frame are also in the mix. They increase the over all white factor and your risk of a lethal foal.

How can a cross be only sometimes lethal?
First the game take the whole range of horses that would have survived but had life long health issues, foals that would have survived a few weeks but ultimately died, etc. and simplifies that down to lethal or not. Second is a genetic concept called penetrance. Genetics is not a simple on/off switch like is often taught in middle school. Some genes just put you at a higher risk. In real life some splash white horses are deaf, others are not and the percentage of deaf ones depends largely on which splash allele is present. But regardless the more white on the horse the more likley they are to be deaf. Same with our KIT mutations the riskier the allele and the more white on the horse the more likley something critical was hit this time.


Remember white markings are broken horses.
Most color genes on horses are mutations (anything outside of the wild horse bay look) and a mutation is a broken gene. That is really important to remember. Some breaks like bay becoming black are pretty trivial and don't do much. Some breaks are more problematic. Every white sock, star, pinto mark etc is a sign of something that is broken and the more white on a horse the more things that are broken. Pigment is vital for many bodily functions and a total lack of it is often lethal. The lethal gene system models this reality. The more you stack risky genes together the more at risk the health of the foal. This is true in real life and in game**.

**Does that mean I am anti paint horse? Absolutely not! I love beautifully marked paints and pintos but I also believe that only irresponsible breeders breed two frame carrying horses together in real life..

Remember adding splash, frame and high white factor parents to the mix greatly increases your risk of a lethal foal.