UBC Theses and Dissertations
The mode of inheritance of the bareback characteristics in Rhode Island red chicks Hill, Stanley Robert Garbott
Experimental work was undertaken in an effort to discover the possible genetic cause of the poor feathering quality of back feathering frequently encountered in the Rhode Island Red breed of domestic fowl which characteristic had severely militated against this particular breed with the rapidly growing importance of the broiler aspect of the poultry industry. Feathering data on the 1948 and 1949 hatches of the UBC strain are presented and analyzed in this light. Data on experimental matings, involving "bareback" Rhode Island Red sires mated to "bareback" Rhode Island Red dams, to slow-feathering Barred Plymouth Rock and New Hampshire dams and to homozygous early- and normal-feathering White Leghorns, are treated in a like manner. Consequent to the observations made and deductions drawn, the writer postulates a "Theory of Inhibitors" as an explanation of this unfavourable feathering aspect of the Rhode Island Red. Four factors are believed to be involved. The experimental work presented was insufficient to demonstrate whether three of these - one "major" and two "minor" inhibitors - were sex-linked or autosomal in nature, while the fourth appeared to act as a sex-linked recessive gene. The major inhibitor apparently did not find expression in the Rhode Island Red and was assumed to constitute a normal complement of the Rhode Island Red’s characteristic type of feathering. In inter-breed matings, however, it appeared to be dominant to normal Leghorn feathering in suppressing tail development. The two minors, in cumulative action with the major, were believed to be responsible for the variations in secondary flight and tail feather development observed in Rhode Island Red chicks. The sex-linked recessive gene apparently gave rise to a retarded type of back feathering, which effect was observed to extend posteriorly to similarly retard the development of the central tail feathers and, in conjunction with the major inhibitor or the two minor inhibitors, was primarily responsible for the "bareback" condition. Further experimental work was indicated to definitely prove this hypothesis and to ascertain the mode of inheritance of the genes involved.
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