NO, I did not mean recessive white as Opal is even recessive to recessive white. Opal has not been shown to be allelic to recessive white, and when crossed with recessive white the F1 generation is BLACK. When crossed for the F2 the results were 50% black 25% White and 25% Opal. TShelton54
In that case it would be proved that opal is not allelic to recessive white. I would be interested in the source of this finding.
Still, dominant white alleles are mostly dominant, so opal doesn't fit.