Why later experiments revised the lacing model

A 1991 study used additional Blue Andalusian crosses to investigate the genetic background of the laced blue pattern. Its results supported an extended-black genotype in the tested Andalusian stock and did not support the presence of a Columbian-type factor. The authors proposed that blue dilution acted differently according to which dark-pigment factors were present.

This later work is valuable precisely because it did not simply repeat every earlier model. It questioned the role assigned to the Columbian factor and distinguished the feather's blue regions from areas that remained black through other pigment and lacing influences. Breed education should therefore explain the well-known visible pattern while acknowledging that detailed genetic models develop through new crosses and observations. A simplified color ratio cannot describe the entire laced phenotype, and historical experiments should not be presented as proof of every current line's complete genotype.