Genes, located in DNA segments called loci, determine an organism's traits through sequences of nucleotides. Mutations in these sequences can alter traits, turning genes into different versions called alleles. Organisms with two identical alleles are homozygous, while those with two different alleles are heterozygous. Dominant alleles override recessive ones, affecting the trait's appearance in heterozygous individuals. Incomplete dominance results in a trait blend from both alleles. Genetic documentation uses uppercase letters for dominant genes (A, B, C, D,...) and lowercase for recessive ones (a, b, c, d,...). For example a heterozygous organism with one dominant 'A' gene and one recessive 'a' gene is denoted as A/a. It is important to note, that multiple alleles at various loci can influence a certain trait, and their interactions, which follow specific rules, allow for the prediction of the genetic outcomes.
The bronze gene (b) is recessive and defines the Bronze turkey's phenotype. Variations in bronze coloration range from shiny iridescent to dull. The black allele (B) is a dominant mutation causing melanism in the whole body. The Black-Winged Bronze allele (b1) is the least dominant. This mutation causes the primary wing feathers to be fully black. The dominance of the genes is as follows: B > b > b1.
The full color expression gene (C) is dominant, while the white allel (c) is recessive and leads to white plumage, regardless of other color genes involved. The gray allele (cg) affects pheomelanin and black pigmentation, with significant impact on Black-Winged Bronze turkeys. The mottling allele (cm) slightly reduces pigmentation in black-based turkeys but moderate in bronze- and black-winged bronze varieties. In combination with the white allele, it is creating a heavy mottling effect. The dominance of the genes is as follows: C > cg > cm > c.
The slate allele (D) dilutes black pigments heavily, giving black birds a greyish-blue appearance with a much lesser effect on red or brown colors. Heterozygous birds (D/d) show some dark speckles, indicating the heterozygousity, while homozygous birds (D/D) have a uniform coloration, which is in general much lighter than heterozygous birds. The dominance of the genes is as follows: D > d.
The brown allele (e) is sex-linked and recessive, changing bronze and black to brown. Males require two copies (e/e) to show brown coloration, while females need only one (e/-). Sun exposure can fade the brown color significantly. The dominance of the genes is as follows: E > e.
The Narragansett allele (n) is sex-linked and lightens turkey plumage by reducing pheomelanin. Males require two copies (n/n) and females one (n/-) to express this lighter phenotype. The dominance of the genes is as follows: N > n.
The pencilling allele (pn) is recessive and creates a vertical feather pattern, but only in the presence of two Black-Winged Bronze alleles (b1/b1) and not in Bronze or Black turkeys. The dominance of the genes is as follows: Pn > pn.
The red allele (R) is an incompletely dominant allele that increases red and dilutes black pigmentation in turkeys. A single r allele slightly increases the bird's red coloration, unlike a completely recessive gene which would not show effects unless two copies are present. The dominance of the genes is as follows: R > r.
The recessive slate allele (sl) uniformly changes the entire plumage to a gray, including areas which the dominant slate allele (D) would not change. It requires two copies (sl/sl) for expression. The dominance of the genes is as follows: Sl > sl.
