Silkie color genetics- any insight?

[Gone fishing12]

http://kippenjungle.nl/wiki/index.php?title=Chicken_Chromosome_Linkages



Size:



adw(autosomal dwarfism)- autosomal, recessive.

https://pubmed.ncbi.nlm.nih.gov/11092317/





dw(sexlinked dwarfism)- sexlinked, recessive.



dwB(bantam dwarfism)- sexlinked, recessive.



Cp(Creeper/short legs)- autosomal, dominant, LETHAL.



https://go.gale.com/ps/i.do?id=GALE...GroupName=tel_oweb&isGeoAuthType=true&aty=geo





Trait:



M(multiple spurs)- autosomal, dominant.



Po(Extra toes/polydactyl)- autosomal, incomplete dominant, expressivity and penetrance extremely irregular.



0(Blue egger)- autosomal, dominant.



br(brown eyes)-sexlinked, recessive.



Comb:



bd(Breda comb/Combless)-autosomal, recessive.



DV(V-shape Duplex comb)- autosomal, incomplete dominant.



DB(Buttercup, Duplex comb)- autosomal, incomplete dominant.



R(Rose-comb)- autosomal, dominant.





P(Pea-comb) - autosomal, incomplete dominant.



R+P(Walnut-comb)- both autosomal, both dominant.



Feathers:



h(Silky)- autosomal, recessive.



F(Frizzle) autosomal, dominant, semilethal.



Na(Naked neck)- autosomal, dominant.



K(late/slow feathering)- sexlinked, dominant.

https://pubmed.ncbi.nlm.nih.gov/2837753/





k+(rapid/fast feathering)- sexlinked, recessive.



Hf(Henny feathered)- autosomal, incomplete dominant, sex-limited.



Pti(Featherfooted)- Autosomal dominant with multifactonal

modifiers (possibly 2 or 3 loci).



v(Vulture hocks/longer leg feathers at the elbow of the leg)- autosomal, recessive.



Mb(Beard)- Autosomal, incomplete dominant, incomplete penetrance.



Cr(Crest)- autosomal, incomplete dominant.



Wc(white crest)-autosomal, incomplete dominant.



Lf(LONG FLOPLUMES)- autosomal, dominant.



mt(non-molt/long tail)- recessive.



Gt(NON-LIMITED GROWTH/long tail)- dominant.



Et(Eartufts) - autosomal, dominant, incomplete penetrance

and irregular expressivity, lethal?



Rp(Rumpless)- autosomal, dominant, lethal?



Skin/Leg:



Fm(Fibromelanosis/dark skinned/dark shanked)- autosomal, dominant, with multifactorial modifiers. As seen in silkies.



w(Yellow-skin/willow-green-shanked)- autosomal, recessive. Willow green like you can see on Easter eggers.



W+(white skin/white-shanked)- autosomal, dominant.



y(sexlinked/white-skinned/white-shanked)- sexlinked, recessive.



Id(dermal melanin inhibitor/ Light/white-shanked)- sexlinked, dominant.



id+(dermal melanin/slaty blue-shanked)- sexlinked, recessive.



W+ + id+(slaty-blue-shank)- (W+autosomal), (id+sexlinked),(W+dominant), (id+recessive).

 

[Gone fishing12]

Primary color pattern

Do you know your chickens foundation color?



It is determined by the 10 E locus series base colors. Poultry Genetics.

The E locus genes, in order of most dominant to most recessive. Genes:



1. E(dominant black/extended black)- examples of this base color can be found in many breeds, from the black Australorp to the white crested black polish. Dominant black is very common. But every black chicken is NOT dominant black, and dominant black chickens aren't always black either, for example my paint silkies are E-dominant black, but they appear mostly white thanks to I-dominant white. There are also black dilutions; Bl-blue, lav-lavender, choc-chocolate. Furthermore two copies of c-recessive white covers black and red pigment. Also, while E-dominant black hens are usually free of color leakage, males are the other hand will commonly have red, gold, or silver leakage on their necks, shoulders, and/or body feathers. Chickens that are solid black without any leakage were selectively bred to avoid color leakage, and black based chickens commonly have black enhancers.



As for black chickens that aren't dominant black, a birchen with a Ml-Melanotic gene appears solid black, as is seen in the FBC Marans, which is why Some FBC Marans are completely black. Note that many FBC Marans blood lines were also mixed with black Marans, so some FBC Marans flocks are actually a mix of ER-birchen and E-dominant black and Ml-melanotic. However, the FBC Marans aren't supposed to be dominant black, but you can't tell the difference between a E-dominant black bird and a ER-birchen + Ml-melanotic bird that appears all black, so it would be hard to enforce the idea that E-dominant black shouldn't be allowed in FBC Marans lines, when, Ml-melanotic is considered to be a trait of the breed variety, and it would be hard to breed out the E-dominant black and leave the Ml- melanotic gene. As they are both dominant and it could be hard to distinguish between the two. Another black enhancer that can make a birchen base bird appear solid black is cha(charcoal).



2. ER(birchen), FBC Marans are considered to be red birchen, but there are many breeds that are birchen that better represent this base color, birchen Cochins are a good example. Birchen chick down is similar to a E-dominant black chicks down, birchen chicks are usually mostly black with a few white or off-white spots on their wings and under belly. Birchen is a common color.



3. ER- Fay(fayoumi birchen), as possibly seen in the silver and gold Egyptian Fayoumi chicken, the Egyptian Fayoumi has many alleles contributing to their appearance besides their base color, they possess pattern genes that give them autosomal barring, those genes being Db Darkbrown and Pg pattern gene. The chick down of the ER-Fay is supposed to be red-brown. This is a rare base color.



4. eWh(dominant Wheaten), think salmon faverolles, they are eWh-dominant wheaten, and they are a excellent example for this base color as the salmon faverolle doesn't have many other feather genes at play, therefore you can really observe the difference in chick down, dominant wheaten chick down is a light cream color, and while adult plumage on hens is usually are a buff or beige color, an adult dominant wheaten rooster has a similar appearance compared to other base colors, such as e+, eb, and ER.



5. e+(duckwing/wild type), the welsummer is the poster child for duckwing, Welsummers are a red duckwing. Side note; in American we commonly call duckwing partridge. So commonly it's called partridge instead of duckwing that you may think of "partridge" as meaning American Partridge, also in America we call eb-"European"-partridge, brown, and for some reason we also refer to duckwing as brown and light brown. e+ duckwing is the original base color, the red jungle fowl is gold duckwing. Duckwing is a common color, to tell the difference between e+ and eb you can look at chick down on birds that Aren't carrying other genes that cause changes in chick down, or you can tell by looking at adult females, e+ hens will have what is called a salmon breast, and eb hens chest will be a similar color brown as the rest of their body. The chick down of e+duckwing chicks, they have very uniform stripes, males will have lighter stripes and females will appear to be wearing winged eyeliner. Homozygous e+duckwing chicks can be sexed by looking at their chick down, the accuracy can be as good as 95%, but unlike the welsummer, not all duckwing based breed verities have been bred for their auto sexing potential, therefore the accuracy of sexing chicks is not going to be as good.



6. eb(partridge/brown), fun fact; brown leghorns most commonly come in e+-duckwing, they can also be actual brown, eb-brown birds will Not have a salmon colored breast feathers on the hens. The eb roosters will look exactly the same the e+ roosters, almost identical. eb-partridge brown leghorns are usually marketed as dark brown leghorns. Partridge/brown is a common color. I have many eb-partridge silkies. A lot of Easter eggers are eb-partridge as well. A eb-partridge chick without any other genes that affect chick down will look chocolate in color, with no stripes or very faint stripes. However many breeds that are eb-partridge carry pattern genes that can cause multiple variations of stripes on the chick down. It should also be noted that, the pattern gene Pg(pattern gene), will Not change eb(partridge) based roosters' juvenile and adult plumage. Currently most eb-partridge based breed varieties have pattern genes, for example the partridge rock is double laced. Ml-melanotic + Pg-Pattern gene = double laced, but this lacing will only show on the females, not the males. Furthermore eb-partridge does Not have auto sexing potential.



7. es(speckled), I found a description, for this foundation color. Described as "speckled head (blurred head)",

"The sixth allele at the E series plumage-pattero locus. Chicks show confused speckled-blurred head pattern. Their back strips tend to be less precise than the

"wild-type chick (item 452) and the ground-color is dusky. Adult males have the "wild-type," e+/e+ coloration. Adult females are very coarsely stippled."

https://digitalcommons.lib.uconn.edu/cgi/viewcontent.cgi?article=1028&context=saes

Just for clarification there were only eight primary color pattern/foundation colors in the "international registry of poultry genetic stocks," which is why es(speckled) comes in as number six in their E series.



8. ebc(buttercup), I can't tell the midfielder genes from the differences in the E locus mutation, but the Sicillian Buttercup is ebc-buttercup. The adult plumage does look pretty similar to most other base colors that have autosomal barring. ebc-buttercup's distinctive difference from other E locus base colors is, the differences seen in the chick down. Buttercup is a rare color.



9. ey(recessive wheaton), recessive wheaton is generally accepted to exist. But no modern breed claims to be exclusively recessive wheaton. As far as I know, the only way to tell the difference between eWh(dominant Wheaten), and ey(recessive wheaten) is though breeding. Dominant Wheaton is only recessive to dominant black and birchen, whereas recessive wheaten is recessive to either all other base colors, except, perhaps recessive, Wheaton might not be recessive to eq(queen Silvia). It is to my understanding that a recessive wheaton has not been crossed to a queen Silvia, and therefore it is not known which of the two would be expressed phenotypically. Supposedly the chick down of recessive wheaten is different from dominant wheaten as well. Recessive wheaten is considered rare.



10. eq(queen Silvia), The Queen Silvia chicken was developed by Swedish geneticist Martin Silverudd the name choice was to honor Sweden's longest reigning queen, Silvia. This is another breed that has pattern genes, among other feather color modifiers, this breed also has autosomal barring. I don't know how eq-queen Silvia differs from other E series base colors. Queen Silvia as a breed is rare and so there aren't many opportunities for getting a queen Silvia chicken, so I don't have any firsthand experience with this base color. This is a very rare base color.

 

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[Gone fishing12]

Update:

Female chickens have a Z sex chromosome and a W sex chromosome. Male chickens have two Z sex chromosomes.

Autosomal basically means NOT sexlinked. An autosomal chromosome is a chromosome that is NOT a sex chromosome. An autosomal gene is a gene that is NOT on a sex chromosome.

Sexlinked means that the gene is on one of the sex chromosomes. Spoiler! Currently all the known sexlinked chicken color genes are on the Z sex chromosome.

Dominant: a dominant trait only needs one gene to result in a specific characteristic(s). A homozygous, heterozygous and hemizygous specimen carrying a dominant trait will be relatively similar overall.

Incomplete dominance: an incomplete dominant trait will have different characteristics depending on whether the organism has one or two copies of a gene. A heterozygous and hemizygous specimen will be relatively similar, while a homozygous specimen will be different.

Recessive: recessive traits need two copies of the gene for a specific characteristic to be expressed. A homozygous and hemizygous specimen will show the characteristic(s) of the gene, a heterozygous organism will not.

Gold v.s. Silver
S(Silver) is a sexlinked, incomplete dominant gene, s+(gold) is a sexlinked, recessive gene, s+(gold) is the absence of S(silver), s+ is gold, S is silver. Silver is not a gold dilution or inhibitor. Silver is a mutation of gold, silver and gold are the same gene, silver is the mutated form of gold. If the Z sex chromosome has a S(silver) gene then it doesn't have a s+(gold) gene. Think of silver and gold as being two different sides of the same coin. A more accurate analogy would be, think of the chromosome as a city, and the locus as the exact address of a single-gene apartment, only one type of gene can live there, and only one gene can live there at a time, there can only be a s+(gold) or a single S(silver) at the gold/silver locus of a Z chromosome.
That said, a rooster can be homozygous or heterozygous for silver or gold. A rooster has two Z sex chromosomes and therefore can have a s+(gold) gene on one Z sex chromosome, and a S(silver) gene on the other. Hens, however, have only one Z sex chromosome and therefore can only ever be hemizygous for silver or gold. 

Gold diluters/gold inhibitors:
Di(dilute)- autosomal, dominant gene. Lightens gold.

ig(inhibitor of gold/lemon/cream) - autosomal, recessive gene. Lightens gold, however the results of this gene vary widely from individual to individual. The amount of change this gene causes to the gold of a particular chicken seems to be random.

Cb(Champagne blond) - autosomal, dominant gene. Lightens gold.

lav(lavender)- autosomal, recessive gene. Lightens gold and black. Lightens gold to a cream color.

Gold enhancer:
Mh(mahogany/red)- autosomal, dominant gene. Darkens gold.

Black enhancers:
Ml(Melanotic/melanised)-autosomal, doesn't always behave dominantly. Darkens and/or increases black.

cha(charcoal/melanised)-autosomal, incomplete recessive gene. Darkens and/or increases black.

Black diluters:
Bl(blue)- autosomal, incomplete dominant gene. One copy lightens black to grey, while two copies, Bl/Bl(splash), lighten black to white/pale grey with flecks of gray.

lav(lavender)- autosomal, recessive gene. Lightens black and gold. Lightens black to a light gray.

choc(chocolate) - sexlinked; found on the Z sex chromosome, recessive gene. Lightens black to a dark brown.

White:
I(dominant white/inhibitor of black)- autosomal, incomplete dominant gene, but leaky. One copy removes most black, two copies remove all black, it can also lighten red/gold pigment.

c(colorless/recessive white) - autosomal, recessive gene. Removes black and red pigment.

mow(white)- autosomal, recessive gene. Removes black and red pigments. This is a mutation of (mo)mottling, birds may not be completely white.

Mutation of dominant white:
Id(dun)- autosomal, incomplete dominant. Recessive to I(dominant white). One copy of the Id(dun) gene paired with i+(absence of dominant white) results in a dun bird, that is a bird that appears chocolate in color. Two copies of the gene, Id/Id(khaki), results in a khaki colored bird.

Is(smoky),-autosomal, considered recessive, dominant to I(dominant white), recessive to i+(absence of dominant white). Two copies of the Is(smoky) gene results in a gray bird. Likewise one copy of Is(smoky) plus one copy of I(dominant white) results in the same gray.

White stripes:
B(sexlinked barring/cuckoo)- sexlinked; found on the Z sex chromosome, incomplete dominant. Causes white stripes on feathers.

Bsd(sexlinked dilution barring)- sexlinked; found on the Z sex chromosome, incomplete dominant. Causes white stripes on feathers of females and causes males to be almost entirely white.

BO or BEsd(sexlinked dilution barring)- sexlinked; found on the Z sex chromosome, incomplete dominant. Causes white stripes on feathers of females and causes males to be almost entirely white.

White spots or white spots accompanied by and attached to black spots:
mo(mottled)- autosomal, recessive gene.

Pattern genes/genes that react with pattern genes:
Co(Columbia)- autosomal, dominant gene. Rearranges the overall look of a base/foundation color, and the particular results depend on what base color your chicken is, and whether there are any other pattern genes present.

Db(darkbrown/black tail)- autosomal, dominant gene. Rearranges the overall look of a base/foundation color, and the particular results depend on what base color your chicken is, and whether there are any other pattern genes present.

Ml(melanotic/melanised)- autosomal, dominant gene. This is a black enhancer that also acts as/reacts with pattern genes.

Pg(pattern gene)- autosomal, incomplete dominant gene. This pattern gene creates penciling on hens by itself. Located on chromosome 1.

cha(charcoal/melanised)-autosomal, recessive gene. This is a black enhancer that also acts as/reacts with pattern genes.

The resulting pattern will differ depending on what foundation color your chicken is.

Spangled: (Db+Ml+Pg).

Laced: (Co+Ml+Pg).

Laced or half spangled: (Co+Db+Ml+Pg).

Double laced or laced: (Ml+Pg).

Penciled: (Pg).

Autosomal barring/black barring: (Db+Pg).

Quail: (Co+Ml).

Incomplete quail: (Co+Db+Ml).

Lakenvelder: (Co+cha).

Unicolor/self: (Co+Db).

Columbian: (Co).

(Co)columbian can not be made on ER(birchen) or E(dominant black).

(Co+Ml+Pg) lacing is made on eb(partridge) foundation color. But it can also be made on e+(duckwing), and eWh(dominant wheaten). These pattern genes on a ER(birchen) foundation color will result in a black bird.

(Co+Db+Ml+Pg) lacing is made on ER(birchen) foundation color. These same pattern genes on eb(partridge), or e+(duckwing), or eWh(dominant wheaten) foundation color will result in half spangling.

(Db+Pg), Autosomal barring will only show up on roosters that's foundation color is ER(birchen). Autosomal barring can be seen on ER(birchen) hens and roosters, eb(partridge) hens, and e+(duckwing) hens.

(Co+Db), Unicolor/self should be made on eWh(dominant wheaten). Unicolor/self is the absence of a pattern, think of the buff Orpington.

(Pg) and (Ml+Pg), roosters will Not show penciling or double lacing on any base/foundation color. Pg(penciling) will only show on eb(partridge), and e+(duckwing) based hens. (Ml+Pg) double lacing can be seen on eb(partridge), eWh(wheaten) and e+(duckwing) HENS. (Ml+Pg) on an E(dominant black) or ER(birchen) bird will result in a black bird, but if you add a black diluter then you can see the lacing. The blue Andalusian is a good example.

(Db+Ml+Pg), spangled breeds are usually ER(birchen), but this pattern is visible on all the common foundation colors with the obvious exception of E(dominant black).

Update:

 

[Gone fishing12]

I've compiled chicken genes, predominantly feather color and pattern influencers, and other physical characteristics. I like to learn about chicken genetics, but I'm especially interested in color genetics, and feather types, among other physical trait genetics.

Feel free to check out my farm facebook

https://www.facebook.com/share/haaMtoQPnsGkwuVZ/?mibextid=LQQJ4d

 

[Gone fishing12]

The methods for sexing day-old chicks:

1. Color sexing- there are many different ways to make color sexable chicks. You can get a autosexing breed. Genes that have auto sexing potential:

• e+(duckwing/wild type) is a E series base color that has auto sexing properties. The female chick down has darker stripes and looks to be wearing black eyeliner.
• ig(cream) is a gold inhibitor. It lightens the chick down of male chicks.
• B(sexlinked barring/cuckoo) is a gene mutation that causes white stripes on the feathers of the birds carrying this gene. This gene has both auto sexing and sexlink potential. It is a sexlinked gene, which is carried on the Z sex chromosome. Or make a sexlink. Sexlinked pairings:
• Homozygous s+(gold) rooster paired with a S(silver) hen.
• Solid colored rooster paired with a B(sexlinked barring/cuckoo) hen.
• choc(sexlinked chocolate) rooster paired with solid colored hens.

1. Vent sexing- if you look in the vent of a chick, and you have really good eyesight, you can see a little clear bump in the vent of male chicks. It's a very tiny bump, and if you have ever seen those heat rash bumps people get, they are tiny clear bumps, it looks like that.
2. Feather/wing sexing- female chicks usually grow feathers faster than their same breed, same line, same gene pool male counterpart. This method works best on full siblings. This method doesn't work on breeds with low sexual dimorphism. This method also doesn't work on chickens with the multifactorial modified slow feathering, as this collection of genes doesn't slow the growth rate k+/k+ chicks primarily wing feathers. In other words it slows down the wing feathers of the k+/- females, making it impossible to feather sex. So some breeds of specific lines can be feather sexed with a high level of accuracy, and some breeds cannot be feather sexed. I had some Anconas, I had one male and two or three females and I could feather sex their offspring with 100% accuracy. Anconas are a fast-feathering breed. I have wing-sex many breeds and some mixed breeds, the accuracy of feather sexing varies widely from breed to breed, and line to line. I had Easter eggers that I had absolutely no accuracy whatsoever. Not all Anconas are feather sexable either. Actually it's been pointed out that for K(delayed feathering), the females would be K/-, and males would be K/K, DF of K for males would slightly increase the effect of the gene, thus making male feathers grow more slowly. That said! Feather sexing is compiled and hasn't been professionally and scientifically researched enough.
3. Feather sexlink- Sex-linked feathering is controlled by locus K on the Z sex chromosome, with four known alleles in the following in order of dominance: Kn > Ks > K > k+

Kn (extremely slow-feathering)

Ks (slow-feathering)

K (delayed-feathering)

k+ (fast normal-feathering)

Other feather growth genes:

t(TARDY FEATHER GROWTH)- autosomal, recessive.

(MODIFIED SLOW FEATHERING)- multifactorial. This combination of genes has no effect on k+/k+. This combination of genes will mess up your ability to feather sex, and the ability to make feather sexlinks.

1. Tail inclination- supposedly, straight tailed chicks are male, and down turned tailed chicks are female. I have never tried this method.
2. Egg dimorphism- historically at least a few chicken breeder could tell the difference between male and female eggs. The round shaped eggs are female, and the pointier, more elongated ones are male. I haven't had any chickens, to my knowledge, that possessed this particular trait. But theoretically speaking it's Not impossible, and people have supposedly used this method successfully. Most of my chickens lay uniformly shaped eggs. But, I have tried using this method, it was highly inaccurate in my experiment.
3. English method- supposedly if you gently pick a chick up by the skin on the back of the chicks neck, a female will kick and a male won't?
4. Shank sexlink- Id(dermal melanin inhibitor/ Light/white-shanked)- sexlinked, dominant. Carried on the Z sex chromosome. id+(dermal melanin/slaty blue-shanked)- sexlinked, recessive. Carried on the Z sex chromosome. y(sexlinked/white-skinned/white-shanked)- sexlinked, recessive. Found on the Z sex chromosome. This skin/shank color gene is not widely known. In a shank color sexlinked pairing, the rooster would most commonly be id+/id+ and the hen would be Id/-(as she only has the one Z sex chromosome), all female offspring would inherit an id+ from their father and the W sex chromosome the female inherits from her mother won't influence shank color, making females id+/-. The male offspring would inherit his mother's single Id gene from her Z sex chromosome, and one of his father's id+ genes, meaning the male offspring would be Id/id+, meaning males would have white or yellow shanks, and females would have a slate/blue/dusty white or willow/dusty yellow shanks, provided they aren't E(dominant black), or ER(birchen) base color. In chickens with the foundation color E(dominant black), or ER(birchen) the Id/id+ male offspring would have almost black shanks and the id+/- female offspring would have black shanks.
5. Combs: at about a month old a male chick of a lot of breeds start to grow a larger, redder crown. This method isn't very useful for silkies.

https://amerpoultryassn.com/2022/06/feather-sexing-in-poultry/



https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6941311/

 

[Gone fishing12]

There are two "layers" that influence shank color.

Dermis is the underlying skin structure & tissue.

Epidermis is the skin that covers over the Dermis.



Skin/Leg:



Fm(Fibromelanosis/dark skinned/dark shanked)- autosomal, dominant, with multifactorial modifiers. As seen in silkies.



y(sexlinked/white-skinned/white-shanked)- sexlinked, recessive. Found on the Z sex chromosome. This skin/shank color gene is not widely known.



The EpiDermis Layer has the following colour options. W+/W+= white shanked, W+/w=white shanked w/w + Id=yellow w/w + id+=willow shanked



w(Yellow-skin/yellow-shanked/willow-green-shanked)- autosomal, recessive.



W+(white skin/white-shanked)- autosomal, dominant.



The Dermis Layer has the following colour options. Female Id/-=white shanked, male Id/Id=white shanked, female id/-=dark shanked, male id+/id+=dark shanked.



Id(dermal melanin inhibitor/ Light/white-shanked)- sexlinked, dominant. Carried on the Z sex chromosome.



id+(dermal melanin/slaty blue-shanked)- sexlinked, recessive. Carried on the Z sex chromosome.



W+ + id+(slaty-blue-shank)- (W+autosomal), (id+sexlinked),(W+dominant), (id+recessive).



w + id+(willow-green-shanked)- (W+autosomal), (id+sexlinked),(W+dominant), (id+recessive).



W+ + Id(white-shank)- (W+autosomal), (id+sexlinked),(W+dominant), (id+recessive).



w + Id(yellow-shanked)- (W+autosomal), (id+sexlinked),(W+dominant), (id+recessive).



Some foundation colors and secondary color genes can change skin and shank color. Without extensive research and testing I would recommend avoiding these genes when choosing breeds for shank color sexlinked breeding program. That is not to say say that you can't make shank color sexlinks with a splash, blue, recessive white chicken, dominant white, mottled, or a chicken with the Di/Di (Gold Dilute) gene, just that the exact effects these feather color genes have on shank color must be determined and understood before you do.



People not fully understanding the correlations between certain feather color genes and shank/sink color genes is why many people think shank color sexing is a myth. While it isn't a myth, shank color sexing is fairly complicated.



Factors That Enhance Black Dermis Color.

E/E (Extended Black)

ER/ER (Birchen) (Enhances to a lesser degree than E/E)



Near black shanks with white soles=W+, Id on E or ER

Black shanks with white soles=W+, id+ on E or ER



Black shanks with yellow soles=w, id+ on E or ER

Near black shanks with yellow soles=w, Id on E or ER



Factors That Dilute Black Dermis Color. Some dermis diluters can cause what would otherwise be white shanks to be a green or willow color. This would absolutely throw a wrench in making a shank color sexlink. That said some dermis diluters can enhance and benefit a shank color sexlinked pairing, it requires a healthy amount of research and real world experience with chicken breeding to best use dermis diluter genes to advance a shank color sexlinked pairing. That said, some dermis diluter genes must be completely avoided, when, choosing chicken breeds/color varieties for a shank color sexlinked pairing. As some dermis diluters nullify the sexlinked shank color properties of the skin/shank color genes, thus making the sexlinked genes appear autosomal, and therefore ruining the method of producing shank color sexlinks.



Dermis diluters:

Bl/bl (Blue)

Bl/Bl (Splash)

c/c (Recessive White)

mo/mo (Mottling)

I/I (Dominant White)

Di/Di (Gold Dilute)

Male B/B, female B/- (Barring/cuckoo)-the barring gene is found on the Z sex chromosome.



A barred chicken breed can be shank sexed, males will have lighter shanks thanks to having a double factor of the barring gene. Please note! This is only the case when you have developed an auto-sexing shank, an auto-sexing shank would be maintained in a breeding line of a purebred breed.



Purebred line of Barred Rock should have the genotype, E/E(homozygous dominant black), S/S(silver, male), S/-(silver, female), B/B(barring, male), B/-(barring, female), w/w(yellow skin), Id/Id(dermal melanin inhibitor, male) and Id/-(dermal melanin inhibitor, females), r+/r+, p+/p+(single comb). With these genes you can shank sex the purebred Barred Rock chicks.



Purebred line of Dominiques should have the genotype, E/E(homozygous dominant black), s+/s+(gold, male), s+/-(gold, female), B/B(barring, male) and B/-(barring, females), w/w(yellow skin), Id/Id(dermal melanin inhibitor, male) and Id/-(dermal melanin inhibitor, females), R/R(rose comb), p+/p+(non-peacomb). With these genes you can shank sex the purebred Dominique chicks.



Gene effects and interactions:

E, w/w, Id, = near black shanks with yellow soles.



Id(dermal melanin inhibitor), Id/Id(males) will have lighter shanks than Id/-(females).



B(barring) is a dermis diluter. B/B(males) will have lighter shanks than B/-(females).



Explanation:

Looking at the genes that affect shank color we see that male offspring have the double factor effect on B(barring) and Id(dermal melanin inhibitor), resulting in lighter shanks on males.

Male purebred Dominique or Barred Rock:

E/E, B/B, w/w, Id/Id.

Female purebred Dominique or Barred Rock:

E/E, B/-, w/w, Id/-.



The autosexing shank takes a keen eye, the differences in shank is subtle. There are also rules for sexing an autosexing shank. From my personal experience the best time to shank sex your Dominique or Barred Rock chicks is when they are about 3 days old. The differences in shank darkness will change with age, you should either separate or mark the females and males if you want to keep up with what sex each individual chick is.



In a line of chickens pure for id+(dermal melanin) and B(barring) the two genes would cancel each other out.

Male: B/B- lighter shank, id+/id+ darker shank.

Female: B/- darker shank, id+/- lighter shank.



The barring gene could potentially be beneficial or complicate things if you are making a shank color sexlinked cross using skin/shank color genes.



A good pairing would be:

E/E, B/B, id+/id+(sire) x E/E, B/-, Id/-(hen)

Male offspring: B/B(DF barring=lighter shank), Id/id+(light shank)

Female offspring: B/-(single barring gene=darker shank than B/B), id+/-(dark shank)



Another good paring:

E/E, b+/b+, id+/id+,(sire) x E/E, B/-, Id/-(hen)

Male offspring: E/E, B/b+(barring would lighten shank), Id/id+(Id=lighter shank).

Female offspring: E/E, b+/-(NO barring), id+(dark shank).



A shank color sexlink would be sexable for a single crossing, just like every other type of sexlinked cross. In a shank color sexlinked pairing, the rooster would most commonly be id+/id+ and the hen would be Id/-(as she only has the one Z sex chromosome), all female offspring would inherit an id+ from their father and the W sex chromosome the female inherits from her mother won't influence shank color, making females id+/-. The male offspring would inherit his mother's single Id gene from her Z sex chromosome, and one of his father's id+ genes, meaning the male offspring would be Id/id+, meaning males would have white or yellow shanks, and females would have a slate/blue/dusty white or willow/dusty yellow shanks, provided they aren't E(dominant black), or ER(birchen) base color. In chickens with the foundation color E(dominant black), or ER(birchen) the Id/id+ male offspring would have almost black shanks and the id+/- female offspring would have black shanks.