Mike, I like this kind of discussion too. I find this stuff fascinating. I\'m surprised that there have not been more diffinitive studies done to actually prove out these theories. I know that when you crossed buff with brown red to make black gold you hade some buff columbian birds segregate out.
That is to be expected since buff birds carry columbian. I would think that if Blue birds carried Columbian you would get columbian type segregants when they were crossed to wheaton to make the blue wheatons. I have not heard of this happening.
I think Blue Andalusians would be E^R/E^R, Pg/Pg, Ml/Ml, Bl/bl. I think the Columbian gene is too much of a eumalenin restrictor to make a solid blue background. If you add Columbian to the above genetic fomula you would get a silver or gold single laced bird. I still think the key to good blue lacing is the melanotic genes. I think there are more than one melanotic gene that affects the intensity of the lacing.
I did find a reference that agrees with me, at least on the Columbian part. I have questions about this study though because it also questions the role of the columbian gene in the single laced and double laced patterns which I do think is pretty well established.
Title: Further study on the plumage pattern of the Blue Andalusian breed.
Personal Authors: Campo, J. L., Alvarez, C.
Author Affiliation: Departamento de Producción Animal, Area de Mejora Genética, Instituto Nacional de Investigaciones Agrarias, Apartado 8.111, 28080 Madrid, Spain.
Editors: No editors
Document Title: Poultry Science
Abstract:
Results of crosses between Blue Andalusian [female][female] and Brown (eb/eb) tester [male][male] showed that the Andalusian stock was E/E and did not carry a columbian-type gene. This fact was further verified by the cross between Blue Andalusian [male][male] and Melanotic Prat (eWh/eWh Co/Co Ml/Ml) [female][female]. It is suggested that the Bl/bl+ genotype is effective in changing black to blue pigment when only 1 eumelanising gene is present in the genetic background, but it is ineffective in the presence of 2 different genes producing eumelanin simultaneously. With an E/E genotype, Bl/bl+ does not change black pigment to blue in the areas where the melanotic (Ml) or lacing (Lg) genes produce black pigment; this results in the laced plumage pattern of the Blue Andalusian (E/E Bl/Bl+Ml-Lg/Ml-Lg). On a non-E/E genetic background, a single dosage of Bl changes the black pigment to blue in the presence of the melanotic or lacing genes. Double-laced phenotypes were not found in either cross; the role of Co in double and single-laced patterns is therefore questionable. Linkage between Ml and Lg was estimated to be 12.2±2.1%.
Curtis
