I've wondered something similar relative to "marker" het pieds versus "non-marker"

Just for sake of arguement (and to cull my hypothesis) what if there were 2 lines of pieds which were compatible? Similar to how mojave and lesser interact (only that in the pied example the combined homozygous offspring is indistinguishable from same gene homozygous).

Say there is a "co-dom" marker pied gene that is compatible with a truely recessive pied gene?

One's with markers could potentially produce homozygous pieds if bred to other markers or they could be bred to true het pieds (non-marker) and produce pieds.

And....just as the previous poster mentioned selective breeding has selected fewer het pieds without the markers?

Just throwing that out there wondering if that's a possiblility?

Easy enough to prove right? Breed marker to marker and then breed the resulting pied to normals to see if you get all markers? Maybe this has been proven otherwise but I thought it was a fun idea.

Great discussion guys!