Genes and the combination of genes in domestic pigeon colourings

Genes as carriers of hereditary information

Genes are a small section on a chromosome which are characterised by a certain effect. In the case of the mutation of the black basic colour to ash red, this effect lies in the change in the mixing ratio of black and red pigments in favour of the red pigments (phaeomelanin). At the same gene locus, the mutation to brown occurred with a different mixing ratio. The mutation from the bar pattern of the wild-type to checks at a different location in the genome causes check spots in the wing shield. At the same gene locus there were mutations to a darker check (T-check) and to the omission of the bars (barless). Further mutations occurred elsewhere in the genome, which in their combination contributed to the variety of domestic pigeon colourations, which are impressively recorded in colour photographs by Levi in the Encyclopedia of Pigeon Breeds 1965, and also by others in later books.

Combinatorics using the example of the basic colours and the pattern genes

Three basic colours (black, ash-red and brown) and four markings (barred, barless, check and T-check) result in 3 x 4 = 12 colourings of the domestic pigeon. In appearance, there are barred, barless, checks and T-checks on blue, ash-red and brown ground colour.

Fig. 1: The base colours black, ash red and brown. Source: Sell, Pigeon Genetics 2012

Epistatic effects using the example of the colour spread factor

If a third level is added, the factor 'spread' as a mutation from wild type, then there are 3 x 4 x 2 = 24 genetically different genotypes. However, apart from small differences due to hetero- and homozygosity, there are only 15 phenotypes: (3 X 4) + 3 (cf. figure 5 in the appendix). This is because Spread largely covers pattern. In genetics as 'epistatic' taken from the Greek. With a black ground colour, one obtains blacks of varying intensity, Spread Ash that vary more in colouration, and solid browns.

Fig. 2: Spread on a black, brown and ash red colour base. Source: Sell, Pigeon Genetics 2012

Gaining knowledge in the early phase of Mendelian hereditary analyses

When dominance, recessivity, epistasis and the combinatorial effects were found through classical hereditary experiments in the first half of the last century, it was known that the Mendelian hereditary factors were located in the chromosomes (Richard Goldschmidt, ‘Die Lehre von der Vererbung’, 2nd edition 6th - 10th thousand, Leipzig 1929, p. 106). Here this source is quoted with the edition number, which shows the interest in scientific questions at that time. The exact location of the genes and the concrete image of the DNA were not known. It was obvious to breeders and interested scientists that the pattern of bars, barless, check and T-check of the blue colour (black ground colour) were repeated in the ash red and in the brown series. The genes were not identified in the laboratory, but by their effects in appearance. This is also how the check gene (C) got its name, flecks in the shield as if hit with a hammer on cold sheet metal. That the pattern did not only exist in the imagination of the scientists could and can easily be shown by the fact that, e.g., the pattern for the check is transferred from one basic colour to the other according to Mendel's rules. This can also be easily shown for the colour spread factor, when Spread Ash mated with blue bar or blue check produce black kittens as well as Spread Ash. This is also true when the blue check cock has additional modifying hereditary factors, such as ice colours in the attached picture from an own recent cross.

Fig. 3: Transfer of the spread gene from a Spread ash red hen to the black ground colour resulting in Spread ash red cocks and and black hens. Source: Sell, Critical Issues in Pigeon Breeding Part VI (2021)

When the illustration of the interaction of the three factor groups like that from ‘Breeding and Inheritance in Pigeons’ in Figure is presented, there will always be someone who protests by saying that he has also raised 'blacks with even blacker bars' from the mating of blue with black. These are weakly coloured blacks with bar markings, distinguished from the darker blacks by modifiers, and are found in many such matings. These aspects are dealt with in the better textbooks after the basic introduction. Such features are also the subject of the series 'Critical Issues in Pigeon Breeding'.

Gaining knowledge in molecular genetic studies

With the development of molecular genetics, genes gained a face in the form of detectable base sequences in certain stretches of chromosomes. This also made it possible to look for differences and similarities in the DNA of individuals with certain characteristics in these sections. It is thus possible to show that, for example, individuals with ash-red colouration systematically have a different base sequence in a certain region than, for example, pigeons with wild-type colouration. If in the experimental analysis the identity of the colour spread factor in Spread Ash and black has been shown by transferring the spread factor of Spread Ash through crosses with blues or checks to blacks, this can be done molecularly in the laboratory by comparing the relevant genomic regions. Epistatic and combinatorial effects was then also the title of an article in which the basic framework of the interaction of hereditary factors obtained in classical genetics is underpinned by molecular genetics (Domyan et al. 2014).

The importance of molecular genetic studies for the practice of pigeon breeding

As stated in the study by Domyan et al (2014), the relationships of dominance and recessivity to each other and the hierarchical relationships of essential hereditary traits are known through classical genetic studies. What has not been uncovered are the molecular genetic peculiarities of these gene loci and the mechanisms of their interaction, which the cited studies contributes to deciphering. If one knows where in the genome certain hereditary information is stored and the base sequence of the DNA sections (genes), then it will also be easier to decide whether similar phenomena are based on identical genes, alleles or other genes with similar effects. It would be interesting for those interested in genetics, especially in the case of the bronze and grizzle variants, which differ externally and also in their heredity. In the case of grizzle varieties, for example, fifteen varieties alone were described in the 2012 book 'Pigeon Genetics'. Studies in recent years have also shown that in pigeons not only the base sequence is responsible for trait expression, but also, for example, copy number variations can be present. Genes are then present in increased or decreased copy number (Bruders et al. 2020, and briefly in Critical Issues Part IV).

Heredity and pigeon breeding

For the practice of pigeon breeding, the molecular genetic studies represent a confirmation of the results of a century of classical genetic analyses. They thus indirectly confirm the breeding strategies derived from classical genetics. Not only for the factors presented above. Actually, one would expect that this would also increase the interest of breeders in heredity issues. Rather the opposite is the case. Of the members active in the pigeon fancier forums on the internet, far more than half will not remember the name Punnett. And of the others, only a minority will know what the didactic tool of Punnett's squares in breeding planning is all about. For breeders more deeply interested in genetic questions and mechanisms, it is a stroke of luck that molecular geneticists have been able to bring the domestic pigeon back into academic research as an object of study. Others usually already have problems in classical genetics with the symbols used only as abbreviations for longer names of hereditary factors. For them, the new terminology seems to build up rather greater fears of contact, despite all the bridging aids (AS).


Bruders, Rebecca u.a., A copy number variants is associated with a sprectrum of pigmentation patterns in the rock pigeon (Columba livia), PLOS Genetics, open access, Published May 20, 2020.

Domyan, Eric T., Michael W. Guernsey et al, Epistatic and Combinatorial Effects of Pigmentary Gene Mutations in the Domestic Pigeon. Current Biology 24, 459-464, February 17, 2014.

Goldschmidt, Richard, Die Lehre von der Vererbung, 2nd edition 6th - 10th thousand, Leipzig 1929.

Levi, W. M., Encyclopedia of Pigeon Breeds, Jersey City 1965.

Sell, Axel, Breeding and Inheritance in Pigeons, Hengersberg 1994.

Sell, Axel, Critical Issues in Pigeon Breeding. What we know and what we believe to know. Anecdotal, Entertaining, and educational comments on open questions, Achim 2021.

Sell, Axel, Pigeon Genetics, Achim 2012.



Figure 4: Sell, Axel, Pigeon Genetics, Achim 2012 and Breeding and Inheritance in Pigeon 1994.



Fig. 5: Combinatorial and Epistatic Effect at the example of base color, pattern and Spread. Source: Sell, Axel, Breeding and Inheritance in Pigeon Breeding, Hengersberg 1994.

Fig. 6: Sell, Axel, Critical Issues in Pigeon Breeding, http://www.taubensell.de