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| Genes Controlling Color & Pattern
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Color Producing Genes:
E
Extended black.
Often called 'nigrum' or 'self black'. Extends black, changes red to black, red inhibitor.
E^R
Birchen.
Resembles extended black, E, but with non-black breaks on head and hackle.
Body is black with some stippling (flecks/dots) of other color. Used as red
inhibitor in Leghorn.
e^b
Partridge (penciled).
Sometimes represented as ep, females have non-salmon breast with stippling. Males are wild-type.
e^Wh
Dominant wheaten.
Female body varies from light salmon to wheat color, some black may be present. Males are wild-type.
e^s
Speckled.
Resembles e^b but with less pronounced stippling. Males are wild-type.
e^y
Recessive wheaten.
Female: resembles dominant wheaten with more coarse black stippling on breast and back. Males are wild type.
e^bc
Buttercup.
Resembles the e^b phenotype.
e+
Wild-type.
Female: breast is salmon brown and devoid of stippling, body is black and brown in stippled pattern.
Males: black breast and abdomen; non-black hackle, saddle and wings.
The order of dominance among the generally accepted E-locus alleles is: E>e+>e^b>e^s>e^y.
Additional alleles have been proposed for the E-locus but research to verify
these as separate alleles has not been done. Every E-locus allele influences
adult female genotype. However, all the adult male phenotypes are the same
as wild-type except for extended black and birchen.
Ml - autosomal 3
Dominant. Melanotic
Black intensifyer, one of the genes which, in concert with Pg and other genes,
is responsible for plumage patterns. There is speculation that there may
be more than one eumelanin intensifying gene similar to Ml and non-allelic.
ml+ - autosomal 3
Recessive, wild-type gene.
Lack of melanotic eumelanin enhancing gene.
mi
Recessive melanotic.
Enhances black, (helps) change red to black. E + mi gives a black chicken.
Mi+
Dominant. Wild-type gene.
Lack of recessive melanotic enhancing.
sg
Recessive black.
Not much is known about this gene. Eumelanin intensifier. There may be a number of genes that play this role.
Mh
Dominant. Mahogany
Restricts eumelanin and enhances the color of red. Rhode Island Red is a
good example. Restricts black in the back and wing of both males and females.
Down color seemes to be unaffected by mahogany.
mh+
Recessive. Wild-type gene.
Lack of mahogany.
Dk
Dark. A proposed gene of an allelemorphic series that darkens the shade of red. Pheomelanin enhancer.
Dk^l
Proposed for the dark brown Leghorn
dk+
Proposed for the wild-type allele.
Color Inhibiting, Dilution, and Pattern Genes:
B^Sd - sex linked
Dominant. Barred Dilute.
Barred Dilute (listed as sex linked dilution by Munro, 1946) is the most dominant allele at the Sex-linked Barred locus (B^Sd >B>b+). Barred dilute is very interesting in that it is epistatic to the expression of pheomelanin, so males with B^Sd can be mated to red hens and the offspring do not express red feathers. This phenomenon does not occur with dominant white (I). Females have blue bars and males can be mostly white. Smyth in Crawford 1990 also states that you can tell the BSdBSd males from dominant white because dominant white doesn't dilute red pheomelanin effectively, but BSd does. For an example of the Barred Dilute gene check out the California Grays (also sold as Production Blacks by Privett Hatchery).
B - sex linked
Dominant. Barring, cuckoo barring.
Causes white barring pattern in red and black, sometimes used as a black
inhibitor, most notably in Leghorns. Cuckoo barring is also an inhibitor
of tissue pigmentation and is responsible for the yellow shanks of Barred
Rocks. Shanks of females can be darker. Barring shows a distinct dosage effect.
B/B gives wider bars than heterozygotes have. Incorporation of the slow feathering
gene results in a cleaner, more sharply defined barring.
b+ - sex linked
Recessive wild-type gene.
An allele of the sex-linked barring locus. Lack of barring.
Co
Incompletely dominant. Columbian
Confines black to hackle and tail in both sexes (called Columbian restriction).
Thought to cause a gradient in color from head to tail. Modifies Wheaten
to Buff Columbian. Has no effect on extended black, E.
co+
Recessive. Wild-type.
Lack of Columbian restriction.
Gr
Dominant. Ginger
This gene may be Columbian, Co, or closely related. This may not be a distinct gene.
Db - autosomal 3
Incompletely dominant. Dark brown
Changes black down of E, ER to reddish-brown. Adults males exhibit a Columbian-type
pattern of black, modifies red to orange-tan. Db is a better restrictor of
black in males than females.
db+ - autosomal 3
Recessive. Wild-type gene.
Lack of dark brown-type Columbian restriction.
pK
Recessive. Pink-eye dilute.
Dilutes both feathers and eye color.
c - autosomal
Recessive white.
Thought to give a cleaner white than dominant white. Varieties of White Plymouth
Rock, Wyandotte, Minorca, Orpington, Jersey Giant, Dorking, Langshan, Silky
and others often carry recessive white genes. Many varieties carry both dominant
and recessive white. Allows dark eyes. Pigmentation in chick down varies.
c^re - autosomal
Recessive, red eyes.
Makes eyes red, as seen in albinos but on a colored bird. Different than c^a.
c^a - autosomal
Recessive, albinism.
Alellic with the recessive white genes. Evident via lack of eye pigment. Some melanin present in chick down.
C+ - autosomal
Dominant. Wild-type gene.
Lack of recessive white mutations.
Comments about the C locus The order of dominance among the recessive white
alleles is: C+>c>c^re>c^a. The presence of other pigment inhibiting
or enhancing genes will influence the chick down color. Some adults have
a grey color.
wh
Recessive. Dorking white.
Makes white bird, different than “c” recessive white.
sw
Recessive. Snow-white down.
The chick down is white rather than yellow.
Bl - autosomal
Incompletely dominant. Blue.
Andalusian blue-dilutes black: blue pigment is a modified black. Two nigrum
genes, E, and one Bl gives a blue chicken; two Bl genes gives splash.
bl+ - autosomal
Recessive.Wild-type gene.
Lack of blue eumelanin dilution gene, Bl.
lav - autosomal 1
Recessive. Lavender.
Associated with poor feather quality and even lack of feathers in some breeds.
Lavender dilutes both black and red; changes black to grey and red to cream.
Blue fowls termed "self blue" are normally lavender homozygotes. A mating
of two lav homozygotes (blue fowls) will produce blue offspring. Lavender
causes dilution by inhibiting the transfer of pigment granules from melanocytes,
which produce them, to the feather structure. Lavender expression in homozygotes
is present in chicks and adults.
I^S - autosomal 1
Incomplete Dominant, partially recessive to wild type.
Listed as a dominant allele because it can be detect it in I //I^S heterozygotes. It is a strange allele in that it is dominant to dominant white in both chick down and adult plumage, but it is recessive to the i+ allele in adult plumage, but not in the chick down. This is a useful quirk because you can track the recessive allele in backcrosses by noting the down color, even if the adults do not express smoky the chicks are still gray.
I - autosomal 1
Incompletely dominant.
Dominant white, influences eye pigment. Inhibits black pigment, eumalanin.
This gene is ‘leaky’ and will allow black specks through. Generally not as
efficient at producing a solid white bird as are two copies of recessive
white. Heterozygotes of dominant white, I/i+ are often grey with the grey
color visible in the chick down. Dominant white dilutes, but does not eliminate,
epidermal melanin.
I^D - autosomal 1
Incompletely dominant. Dun
Inhibitor gene, allelic with dominant white.
i+ - autosomal 1
Wild-type gene. Lack of dominant white.
Lav+ - autosomal 1
Dominant, wild-type gene.
Lack of lavender trait.
Grey no symbol
Recessive.
Dilutes black to brown/grey.
S
Silver and Red-Gold This gene is called 'silver'. Inhibits red pigment,
pheomelanin. The expression of silver is sometimes affected by hormonal levels
and is considered to be incompletely dominant and highly influenced by modifying
genes.
s+ - sex linked
Wild-type, recessive.
This gene is sometimes called 'gold'. Invokes red pigment.
Di
Dominant. Red diluter
Dilutes red, changes red to buff.
di+
Recessive. Wild-type gene.
Lack of red diluter.
rs
Recessive. Red spash white.
Two copies of this gene give a white bird with spashes of red and black.
Chicks are white with a red head spot. This gene may be extinct now. It was
first isolated in a line of Rhode Island Reds, but it was not maintained
nor has it be re-identified.
ig
Recessive. Cream
Dilutes red. A major pheomelanin dilution gene. The gene symbol derives from "inhibitor of gold".
Ig+
Dominant. Wild-type gene.
Lack of cream dilution.
Cb
Dominant. Champagne blond
Inhibits pheomelanin (red / gold). The presence of the gene is not observable on the wild-type down
cb+
Recessive. Wild-type gene.
Lack of champagne blond, dilution.
Pg - autosomal 3
Dominant. Pattern gene
Responsible for the patterns of plumage. The pattern gene doesn’t seem to
express in the absence of Ml in combination with some of the E locus alleles.
See text. The pattern gene with Columbian-like restrictors is believed to
be responsible for autosomal barring.
pg+ - autosomal 3
Recessive. Wild-type gene.
Lack of pattern gene.
pi - autosomal 1
Recessive. Pied.
The pied pattern is recessive black and white as in Exchequer Leghorn. Research
has shown that the pied and mottle patterns are due to the mottle gene. It
is no longer accepted that 'pied' is a distinct gene from mottle, however
it is not known why the mottle gene causes the pied pattern in some birds
and the typical mottle pattern in others. Mottle causes a white tip at the
distal end (end farthest from the skin) of the feather. Chicks with extended
black and mottle (E/E mo/mo) as in the Exchequer Leghorn will often have
black restricted from the belly and sometimes the head.
Pi+ - autosomal 1
Wild-type gene. Dominant.
Not pied.
mo
Recessive. Mottle
Makes a white tip on end of feather. Changes a black bird to Mottled and
a Buff Columbian to a Mille Fleur. Dilutes epidermal melanin. There may be
several alleles corresponding to this locus or non-allelic modifying genes.
“pi” is now called “mo”.
Mo+
Dominant. Wild-type gene.
Lack of mottling.
no symbol
Erminette
Black spots and flecks, variable black and white feathers, similar to pied.
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This page and it's contents are not to be copied or re-distributed in
any way. The information contained herin was taken from extracts of Crawford’s book ‘Poultry Breeding and Genetics’, Hutt’s book ‘Genetics of the Fowl’, and partly from discussions with Dr. Ron Okimoto, Dr. Caveny and Dr. Tom Whiting as well as others. The bulk of which has been copied with the permission of Lee Seller from the ‘Poultry Genetics for the Non-Professional’ web site. They are only to be used for educational
purposes as they pertain to our discussions here on this site. Thank you
for your understanding and compliance.
If you wish to see a similar version of this information
as it was written by the Sellers please visit their site @: Genetics for the Non-Professional
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