1. The chromogen gene for color, CC, acted as a simple dominant.
2. The extension of black pigment, EE, was inherited on a simple monohybrid basis.
3. The heterozygous extension and chromogen genes (Cc Ee) had a balanced relationship. This combination of heterozygous factors weakened the expression of the black melanic pigment in the presence of two or more doses of buff.
4. Buff color was controlled on a dihybrid basis, the following symbols being used, Bu Bu Bu' Bu'.
5. Three or more doses of the buff genes in the presence of homozygous color factors, CC, were epistatic to black, and gave a buff color.
6. Two or more doses of the buff color determiners were epistatic to black when they were in the presence of both the extension of black and chromogen factors in a heterozygous state.
7. When the extension factor was homozygous, EE, the buff color was hypostatic to black if not present in three or more doses.
8. All the factors included thus far in the summary were autosomal.
9. The sex-linked factor for barring (BB and B-) appeared to act as a simple dominant to black and buff colors.
Knox, C. W.
"The genetics of poultry color in poultry,"
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station): Vol. 8
, Article 1.
Available at: https://lib.dr.iastate.edu/researchbulletin/vol8/iss105/1