Genetics of the buttercup plumage pattern.

Genetic analysis of the Buttercup breed of chickens indicates that they carry the buttercup allele (ebc) at the E locus, modified by the columbian-like primary pattern mutation Db and a secondary pattern gene resulting in autosomal barring. The interactions between ebc and the Db alleles are clarified by both F2 and testcross data. Homozygous ebc in the absence of Db results in a modified stripe pattern, whereas the light parallel back stripes are irregular and wider than those of wild type chicks. The dorsal head stripe is also broken and irregular, while the ground color is of a lighter shade of tan. Adult ebc/ebc db+/db+ males are typical black-breasted wild types as suggested previously by Brumbaugh and Hollander (1965). Adult females closely resemble the brown (eb/eb) phenotype. Further proof that the buttercup gene is an allele at the E locus is provided by F2 segregation data for crosses between Buttercup (ebc/cbc db+/db+) and Light Brown Leghorns (e+/e+ db+/db+) and Black Langshans (E/Edb+/db+).