A member asked what causes variations in the amount and presentation of black feathers on a bird that has one copy of the dominant white gene when working with the Erm project color.
The dominant white gene (I) produces the following:
1. A white homozygote (I/I) which results in a white phenotype
2. A heterozygote (I/ I+) which results in a black-flecked phenotype
3. A homozygous recessive (I+/I+) which results in a black phenotype.
Modifying genes, which limit or expand the amount of black on a heterozygote, affect the overall number of black feathers present on the plumage. The modifying genes also affect whether the black plumage feathers will be solid black.
What percentage of black feathers should one realistically strive for when working with the Erm project color in the Ameraucana breed?
If you explore the historic American Erminette breed that is not yet approved, the proposed standard calls for the plumage to have solid white feathers with solid black feathers randomly dispersed in the ratio of 85% white feathers and 15% black feathers.
One may wonder, how did the American Erminette breeders select the above percentage?
It was selected based on a study completed by FB Hutt entitled “The Genetic Basis of the Erminette Breed of Fowls.” In FB Hutt’s study, in a random sample of 100 feathers pulled from the side and breast of one bird, 85% were all white and 15% showed some black.
One must wonder, if FB Hutt had pulled samples from another American Erminette in the pile, what would the percentage have reflected?
So, what would be a realistic percentage of white to black feathers for one to strive for?
Based on the modifying genes, a specific percentage cannot be achieve consistently, and one would wonder how a poultry judge would assess a bird for such.
Based on plumage colors that are presently approved in the APA standard and their verbiage, it would seem most advantageous to simply strive for 1) More than 50% black feathers, 2) Less than 50% black feathers, or 3) A relatively even percentage of white and black feathers.
Just some food, or feathers, for thought as you are working with the Erm project color. 🙂
