So, I've been reading up on horse genetics for RL. And came across something that's interesting. We all know that having homozygous WW results in Lethal white. But in RL, homo Rn results in a foal dying in the womb. Is this an oversight in the genetics?

Oooh, I didn't know that Dimmy! D:

Crazy, right?

I had a look and it seems that although that used to be thought to be true, it's not actually true.

"Although it has been suggested that Roan is a homozygous lethal, evidence from the Quarter Horse breed indicates otherwise. Production records have documented the existence of Roan Quarter Horses that produce 100% Roan foals. DNA tests have confirmed homozygosity in the genomic region that contains the Roan gene."

Gemini is correct. It stems from the fact that a heterozygous roan and a homozygous roan both look very similar. So, people kinda thought that since there wasn't any noticeable difference, that homozygous roans didn't exist.

Thanks, guys! This cleared up the confusion for me.