Chicken Color Genetics

Welcome to my Genetics page! Breeding chickens is my hobby and my passion is their color genetics. After the wall of words you will find screen shots of some volunteer online teaching that I've done in my spare time throughout the years. I hope you find this page helpful this page. 

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Terminology:

Chromosome – Long strand of genes.

Homozygous – a trait is inherited from both parents.

Heterozygous – a trait is inherited from only one parent.

Hemizygous – a female that has a single copy of a sex-linked trait.

Allele – this word basically means “version” of a gene. For example, if green were a gene then hunter, forest and olive would be alleles of green. A gene can have only one version, or a gene can have many versions. A chicken can have no alleles of a gene, one allele, two different alleles of the same gene, or two of the same alleles. If a chicken inherits the same version of a gene from both parents, then the bird id homozygous for that trait.

Locus – gene location on chromosome (Loci – plural of locus)

Autosomal gene – a gene that is located on any chromosome except the sex chromosomes.

Sex-Link gene – a gene that is located on a sex chromosome.

Dominant – a trait that expresses when either heterozygous or homozygous.

Incomplete Dominant – a trait that expresses partially when heterozygous and fully when homozygous.  

Wildtype – original version of a gene.

 

Base Color of ALL chickens

Eumelanin controls black pigment and pheomelanin controls brown pigment. In chickens. The eumelanin gene is often abbreviated as e-locus. There are several alleles of the Eumelanin gene.

Common e-locus alleles found in the United States

E, E^R, e^wh, e+, e^b
- Extended black (E), solid black

- Birchen (E^R), Brown Red color (crowwing pattern)

- Dominant wheaten (e^Wh), Wheaten color (duckwing pattern)

- Wildtype (e+), black breasted males, salmon breasted females (duckwing pattern)

- Brown (e^b), brown, brown breasted females (duckwing pattern)

 

Eumelanin enhancers (genes that intensify or extend black)

Ml and cha

- Melanotic (Ml) is incomplete autosomal dominant. It causes black areas to extend to parts of the body beyond where they otherwise would be without the gene. This gene also thickens pattern lines. According to Carefoot (1990), Melanotic and pea comb genes are only 46 loci away from each other on the chromosome they share, thus making the two genes linked to each other. In 2001, Carefoot suggested that Ml may be allelic to Cha, the gene that causes the head and upper neck of a chicken to be black.

- Charcoal (cha) makes the chicken’s head and upper portion of the neck black.

 

Eumelanin diluters (genes that reduce or fade gold)

Bl, lav, I, ID, IS, choc, c

- Blue (Bl) is incomplete dominant. When heterozygous black areas are changed to shades of gray. When homozygous black areas are further diluted to splash (white with splashes of gray).

- Lavender (lav), changes black areas to light gray, changes gold to yellow. This gene is recessive.

- I (information will be added soon)

- ID (information will be added soon)

- IS (information will be added soon)

- Chocolate (choc) is sexlink recessive. When homozygous (male) or hemizygous (female) the gene changes black to chocolatey brown. When heterozygous (male) there is no change to the phenotype.  

- c (information will be added soon)

 

Pheomelanin enhancers (genes that intensify or extend gold)

Mh, Dk1, Dk2

- Mahogany (Mh) changes gold to a rich shade of cherry red.

- Dk1 (information will be added in the future)

- Dk1 (information will be added in the future)

 

Pheomelanin diluters (genes that reduce or fade gold)

 S, Di, Cb, ig

- Silver (S), changes gold areas to white. It is a mutation of the wildtype gene gold. Silver is sexlink dominant, although heterozygous males may be tinted or have gold leakage. Silver males can have the genotypes S/S or S/s+ and silver females can have the genotype S/-

- Dilute (Di) does exactly what its name suggests – dilutes gold to yellow. This gene contributes to the color buff.  

- Cb (information will be added soon)

- ig (information will be added soon)

 

Modifying genes (genes that modify the e-locus alleles)

Pg, Db, mo, B, Bsd, Er, Co

- Pattern gene (Pg) (information will be added soon)

-  Dark brown (Db) produces black tailed red patter by pushing black off the body/wings/neck and into the tail. The effect is stronger on males than females. The gene can counteract the effect of Columbian and is linked to melanotic. Juveniles with Db will be either brown, or black with a brown head.

- Barring (B) is a sexlink gene. Males that are barred can be either homozygous or heterozygous for the gene. Females that are barred are hemizygous for the gene. Males can pass Barring to both genders of offspring. Females can only pass the gene to their sons. The gene causes periodic temporary pauses in the pigmentation of feathers while they grow, thus creating white lines on the feathers. A chicken can have any eumelanin allele and be barred, as the barring gene is not linked to any color genes.

- B^sd is an allele of barring. This gene causes wide bands of barring and dilutes the base color, creating an overall faded messy barred appearance on females and heterozygous males. Homozygous males are nearly completely white.

- Erminette (Er) is somewhat rare in the USA. This pattern phenotypically is remarkably similar to heterozygous dominant white with homozygous extended black.

- Columbian (Co) makes neck and tail areas on chickens darker than they otherwise would be without the gene.

 

Two types of white

- Dominant white (information will be added soon)

- Recessive white (information will be added soon)

 

Other interesting genes

Frizzle, silkie, soft/hard feathers, fast/slow/tardy feather growth, feathered legs/feet, stubs, vaulter hocks, crest, tufts, muff/beard, naked neck, scaleless, rumples, non-molting, wry tail, henny feather.

(information will be added soon)

 

Combs and their Genes

Single, pea, rose, walnut, duplex, buttercup, breda, rough, sprigs

(information will be added soon)

 

Egg color genetics

(information will be added soon)

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Everything that I have learned about chicken color genetics and inheritance is from studying the information in this research-based website: