I think I may have encountered that gene myself. I wonder if it's part of the reason steel is considered so mysterious?
My SF never behaved like typical steel carriers, or even super steels are supposed to, always throwing more dark and false black kits than they ever should have when crossed to agouti mutts. ( SF probably shouldn't have steel, but I've been paying attention, SF from all over the place have been shown to have it)
Anyway, I'd be lucky to get three visual steels from a litter of 12. The rest would all be black.
If my rabbit's were Aa __ __ __ EE and aa __ __ __ EdEs the probability would have been about right.
A lot of people explain the high incidence of blacks with the pairing of steel (Es) and non-extension (e), but so far, no non-extension has been found in my SF stock or the mutts I crossed them to.
I've also gotten "selfs" from an agouti buck who didn't carry the gene to produce them (a). He fathered large litters prior to true genetic self does and never once producing a self kit. Crossed to a NZB...somehow, I got self kits. That rabbit never threw agoutis, she was either a super steel...or...Ed Es? Perhaps he had a copy of non extension that was never passed to any of his numerous offspring (Currently, a large portion of my herd), but that still doesn't fully explain the higher incidence of "self" kits in the SF cross litters.
Another breeder who was working with the same rabbit lines had assumed self was dominant and agouti was the recessive color based on how difficult it was to get her SF crosses to produce visual steel or agouti kits!
If it is what I've been trying to work past, I wouldn't think it would be all that rare in the breeds that have it.
If I was actively looking for the gene, I'd start with NZB, SF, and Americans.
