Name: Smoky. Symbol: I^S
Comments: The smoky gene is an allele belonging to the dominant white locus. Smoky is dominant to dominant white in both chick down and adult plumage in that extended black with I/I^S (E/E I/I^S) results in grey chick down and adult plumage. Research to date indicates that i+/I^S heterozygotes express more the wild-type phenotype with respect to this gene indicating a recessive character with respect to the wild-type. The melanosomes resulting from the expression of smokey resemble those resulting from Andalusian Blue. Smoky dilutes black much more than red/gold.
A useful note : smoky is dominant on the chick down of I^S/i+ heterozygotes in that down that should be black is gray. This should help people introgress the gene because it isn't fully recessive to wild-type. They can do repeated backcrosses and still identify the birds that carry the allele.