HGG Community Forums

I'm looking for more info about the lethality levels of the splash white genes, specifically SW2 and SW3. The only info I'm finding is the blurbs in the GMT lab, which, while helpful, don't really give me a complete understanding of how careful I should be when breeding horses with these genes. Up to this point, I've simply avoided using these two genes at all.

SW2 blurb: "Splash 2 is caused by a different gene from normal splash (PAX3). It is more aggressive and results in bigger white markings. It is homozygous lethal and lethal with SW3. Counts as a pinto gene."

Splash blurb with SW3 info: "The splash gene creates bottom-up white markings on a horse that look like it was splashed with paint. SW1 is the most common type of splash and SW1/SW1 has more white than a single copy. SW3 is a very loud version of splash and can form lethal crosses. SWM (Macchiato) is a loud, lacy expression of splash that also causes cream-like coat dilution. Counts as a pinto gene."

My pressing questions are:
1. Can SW2 or SW3 be lethal when crossed with SW1, SWM, or any KIT genes?
2. Can SW2 or SW3 be lethal in heterozygous form when combined with high white factor?