What is covered by Dominant White in Pigeons

What is covered by Dominant White in Pigeons

Dominant white, an early described but long overlooked hereditary factor

In 1925 Joseph R. Walker had presented his analysis of white colouration, and among them Dominant White. In homozygosity, white or almost white colouring is caused by the factor. Heterozygous are largely white, but also have coloured feathers to an appreciable extent. The variation in F₁ may be seen in the fact that the factor covers other factors present in the genome in different ways (Sell, 2012, 2015). A Dominant White (Wh) that genetically has a black or heterozygous black/dominant red base colour will inherit differently than Dominant White based on pure Dominant Red.

Fig. 1: Stralsund of the flying type (dominant white) x blue check homing hen with two differently coloured youngsters. The black-grizzle youngster shows that the male is at least heterozygous for both black pigment and the colour spread factor. Next to it a tail-marked juvenile from white parents with 'flash-grizzle'-like brightenings in the tail, pearl-eyed like the parents.

The factors hidden under the epistatic (covering) white can be revealed by mating back to solid colours and in an F₂. Most of the tested whites in the own loft had a dominant red base colour, some had a black one. Often the colour spread factor is revealed in crosses. Besides this also a dominant grizzle factor, identical or similar to grizzle (G). Walker (p. 598) also received coloured kittens from a mating of F₁ among themselves. From his crossings, he concluded that there was a mendelian factor that was independent of the other white factors. After crosses, and from pure white pairs, not just one time, magpies and tail-marked whites are raised. They resemble flash grizzle in the tail. Platinum was also discovered after crosses among the white Pomeranian Eye-Crested Highflyers, anchored in the breed decades ago (Sell, 2012, pp. 169ff., 476f.) and were used in this project as selfs for backcrossing.

Fig. 2: Flash-Grizzle-like lightening at tail-marked young from dominant white Stralsund Highflyer of the flying type at the author

Selective documentation of platinum-coloured grizzles from a back-mating project of F₁to Self Coloured Pomeranian Eye Crested Highflyers

A backcrossing project from an initial cross of a dominant white Stralsund with a Spread Ash Pomeranian Eye Crest was documented in 'Critical Issues' part V. Informative for those seeking empirical findings on the relationship between dominant white and grizzle variants. From the project, the following are selected authentic photos of grizzles and mottled heads, homozygous for platinum, heterozygous for grizzle.

Fig. 3: The barred heterozygous grizzle females are lighter in colour and resemble purebred grizzles in some other breeds. Such animals, lacking Spread, were named White Grizzle by Bonhote and Smalley (1911). The fuzzy bars may be due to the smoky factor. However, not every lighter than normal coloured grizzle is thus homozygous for the grizzle factor.

Fig. 4: When the colour spread factor is added, the plumage becomes uniform. At platin hens dark-grey, at non-platinum black. The markings are covered. Possibly the check markings are hidden underneath. The combination of platinum, heterozygous grizzle and Spread results in mottled heads.

Fig. 5: The two cocks are brothers. One is a platinum bar with grizzle (at the left). Next to it a platinum self with Spread, but lacking grizzle.

Fig. 6: Finally, two kittens out of the shown platinum male and one of the grizzle platinum bar females. A barred platinum coloured juvenile non-grizzle and a platinum mottled head with Spread.

Literature:

Bonhote, J.L., und Smalley (1911). On the colour and colour pattern inheritance in pigeons, Zoological Society of London, Proceedings, pp. 601-619

Sell, Axel (2012), Pigeon Genetics. Applied Genetics in the Domestic Pigeon, Achim.

Sell, Axel (2021), Critical Issues in Pigeon Genetics. What we know and what we believe to know. Anecdotal, Entertaining and Educational Comments on Open Questions, Part V, 80 p. Softcover, Achim.

Sell, Axel (2015), Genetik der Taubenfärbungen, Achim (out of print)

Sell, Axel (2021), Verständnis und Missverständnisse in der Taubenzucht. Anekdotische, unterhaltsame und lehrreiche Anmerkungen zu offenen Fragen, Teil V, broschiert, 60 S., Achim

Walker, Joseph R. (1925), Inheritance of White Plumage in Pigeons, Genetics 10, pp. 593-604