Inheritance of the spangled plumage pattern and the marbled chick down phenotypes of the silver‐spangled Hamburgh Bantam

Publisher Website
Google Scholar
Abstract
1. An investigation was conducted among the progeny from crosses between Silver‐Spangled and Gold‐Pencilled Hamburgh bantams, and between Silver‐Spangled Hamburgh and Double‐Laced Barnevelder bantams. 2. Two subjects were studied: the relationship between three plumage pattern phenotypes, spangling, transverse‐barring and double‐lacing, all of which are arrangements of eumelanin expressed on a background of phaeomelanic pigmentation and the inheritance of the marbled chick down of the Silver‐Spangled Hamburgh bantam. 3. Examination of the F2 generations demonstrated that, in conjunction with silver (S) gene(s) and extended black (E) alleles at the E‐locus the silver‐spangled phenotype can be produced by the addition to the genotypes of the Gold‐Pencilled Hamburgh, homozygous ebc (Db‐ml+‐Pg), and Double‐Laced Barnevelder, homozygous eb (db+‐Ml‐Pg), of Sp and Db genes respectively. Consequently Sp and Ml are one and the same gene, for which I retain the symbol Ml, and the genotype of the Silver‐Spangled Hamburgh is homozygous E (Db‐Ml‐Pg), where the buttercup (ebc) and brown (eb) are alleles of the E‐locus and Db, Ml, Sp and Pg are respectively the eumelanin restrictor dark‐brown Columbian, the eumelanin extension melanotic, plumage pattern spangling and the pattern gene. 4. The exact correlation between S/‐ E/E Db/Db and the marbled chickdown phenotype demonstrated the latter to be a pleiotropic effect of Db/Db, thus enabling the mapping of Db, Ml and Pg in group 3 on chromosome 1.