Well, she is an overo. She has no white over her back (belly spots only). The one solid spot is more irregular and splashy than round. She has a solid colored tail, one blue eye (which I read was more common in overo coloring), and the white on her legs are very low, not extending above the knees.
So does this mean she has no chance of being homozygous, because she is not a tobiano? I still am making payments on her, so I don't yet have the papers in my hand, and can't remember the color pattern of her sire/dam. If her sire/dam were both tobiano and she turned out overo, could she still be homozygous? Is it even possible to produce an overo out of two tobianos?
Also, I read that if you have an overo that carriers a lethal white gene (as you said a homozygous overo would), you need the other parent to also be a carrier for an actual lethal white to occur. The stud I want to use is a tobiano. The article also said tobianos can very very rarely carry a lethal white gene. If she did carry lethal white, breeding her to a tobiano would effectively keep her from producing lethal white correct?
I've always had it in my mind from breeders and trainers that it is never a good idea to cross over x overo as the chance for LWS is much too great.