Chicken Genetics 101

[Brahma Chicken5000]

I will be giving a presentation on chicken genetics to my mother’s science classes over spring break. I know the basic genetics of combs, egg color, cresting, Silkie feathering, Frizzle feathering, Naked Neck complete and codominance.
Would some of you genetic experts please shed some light on the following; shank color genetics, skin color genetics, feathered legs vs clean legs genetics, and the basics of plumage color genetics?
Thank you.

 

[Brahma Chicken5000]

Also are 4 toes dominant or recessive?

 

[sylviethecochin]

@nicalandia, @Sneebsey, @The Moonshiner?

Plumage is what I pay attention to; all I can tell you about skin colour is that white is dominant to yellow. Also, Fibromelanistic is incompletely dominant; I'd bring that up because a picture of an Ayam cemani on the board is probably going to catch their attention.

With plumage, you have e-locus genes and regular colour genes. E-locus genes give you the pattern and colours of the paint-by-numbers chicken. E is solid-coloured for black, for instance. e+ is duckwing, with gold shoulders, neck, and wingtips on the males, and brown body and gold chest on the females. (sexually dimorphic colouring=expresses differently on males than on females) e^b is partridge, which is like Duckwing, but the non-black feathers are laced with black.

The other colour genes help you modify the colours of the paint-by-numbers template. Black can be diluted to Lavender by two recessive Lavender genes; it can be diluted to blue by one codominant splash gene; it can be diluted to almost-white by two co-dominant splash genes. It can also be changed to white by the I gene, which is dominant white, and a mutation of black. It can be changed to chocolate by a recessive chocolate gene. It can be made stripey by barring (dominant), which removes pigment in stripes.

Gold can be changed to silver by the silver gene, which is a mutation of the wild-type gold gene. Gold can be darkened to almost red by the Mh (mahogany) gene, or made very pale by recessive ig or by dominant Cb or by dominand Di.

Those are the very basics. Do you want to get into lacing and dark brown and melanistic and charcoal? Because for a presentation, I suspect the above is enough to be getting on with.

Having an extra toe is mostly dominant, but it doesn't always happen. What happens is that when the zygote is formed, different concentrations of growth hormones in different places triggers growth. Sometimes the gene that is nominally dominant just doesn't express as well as it should, and the hormones are moved, and that extra toe just doesn't form.

 

[Brahma Chicken5000]

@nicalandia, @Sneebsey, @The Moonshiner?

Plumage is what I pay attention to; all I can tell you about skin colour is that white is dominant to yellow. Also, Fibromelanistic is incompletely dominant; I'd bring that up because a picture of an Ayam cemani on the board is probably going to catch their attention.

With plumage, you have e-locus genes and regular colour genes. E-locus genes give you the pattern and colours of the paint-by-numbers chicken. E is solid-coloured for black, for instance. e+ is duckwing, with gold shoulders, neck, and wingtips on the males, and brown body and gold chest on the females. (sexually dimorphic colouring=expresses differently on males than on females) e^b is partridge, which is like Duckwing, but the non-black feathers are laced with black.

The other colour genes help you modify the colours of the paint-by-numbers template. Black can be diluted to Lavender by two recessive Lavender genes; it can be diluted to blue by one codominant splash gene; it can be diluted to almost-white by two co-dominant splash genes. It can also be changed to white by the I gene, which is dominant white, and a mutation of black. It can be changed to chocolate by a recessive chocolate gene. It can be made stripey by barring (dominant), which removes pigment in stripes.

Gold can be changed to silver by the silver gene, which is a mutation of the wild-type gold gene. Gold can be darkened to almost red by the Mh (mahogany) gene, or made very pale by recessive ig or by dominant Cb or by dominand Di.

Those are the very basics. Do you want to get into lacing and dark brown and melanistic and charcoal? Because for a presentation, I suspect the above is enough to be getting on with.

Having an extra toe is mostly dominant, but it doesn't always happen. What happens is that when the zygote is formed, different concentrations of growth hormones in different places triggers growth. Sometimes the gene that is nominally dominant just doesn't express as well as it should, and the hormones are moved, and that extra toe just doesn't form.

Thank you Sylvia. For plumage color I was just going to go over extended black and dominant/recessive white.
What letters represent white and yellow skin color?

 

[sylviethecochin]

Thank you Sylvia. For plumage color I was just going to go over extended black and dominant/recessive white.
What letters represent white and yellow skin color?

W+ and w, respectively. Also, fibro is Fm.

 

[Brahma Chicken5000]

W+ and w, respectively. Also, fibro is Fm.

Thank you. Are feathered legs dominant?

 

[pennyJo1960]

Not sure if this would apply but
Black Sex-linked

There are two important genes that must be a part of a black sex-linked cross; the E locus allele called extended black (E) and the sex-linked barring gene (B). The Barred Plymouth rock carries both E and B and both genes are used as the female side in commercial black sex linked crosses while the male side of the cross is a Rhode Island Red or a New Hampshire. Birchen birds at times can be used in black sex linked crosses. It is best to leave the use of birchen birds to individuals that have tested the birds for the correct genotype. If birchen birds do not have the correct genotype, the offspring will not be black sex linked.

A few specifics to remember about a black sex-linked cross are:

1) the female must carry sex-linked barring (barred),

2) the male cannot carry sex-linked barring (male cannot be barred),

3) one of the birds must be homozygous for extended black or carry two extended black genes and

4) neither of the birds can carry dominant white or in other words be a white bird. Some recessive white birds may work on the male side of the cross but you never know if it will work or not work. So I suggest not using white birds.

5). Almost any variety (color) of male (not including white or barred) can be used in a black sex linked cross. White birds sometimes carry dominant white and or barring which would not work in a black sex linked cross. White males that do not carry dominant white or barring will work as the male in a black sex linked cross. White males like the white wyandotte or the white plymouth rock will work if they do not carry dominant white or barring.

In a black sex-linked cross, the female will only contribute the barring gene to the male offspring. So the adult males will be black and barred. The female offspring will receive their sex linked trait from the father; in this case, the recessive gene for no barring. So the females will not be barred as adults.

It is also important that the chick down has a black dorsal surface, back and top of the head; this allows for the barring gene to be expressed as a white or cream spot on top of the male chicks head. See Illustration 5. This is why a white bird that carries dominant white cannot be used to produce black sex linked chicks. The top of the head would be white and the white spot will not show. Males that carry barring can not be used because the males will produce females chicks with white spots on their heads.

The top of a female chicks head will be a solid black color. See Illustration 6. The chicks in the pictures do not have a white belly like many other black sex linked chicks.

Illustration 5 male black sex-link Illustration 6 female black sex-link




Examples of breeds that can be used for black sex linked crosses.


1 Male carries the blue egg shell gene.
2 Not a good choice may carry barring.
3. Carry the genes for white egg shell.

Feather Sexing Chicks

Color sexing chicks can be a difficult task and is dependent upon the phenotype of the chick. If a chick does not have the correct down color, then you can not color sex the chick. There is a way of using another sex-linked trait to sex chicks based upon the size of the primary and secondary feathers on the wing of a newly hatched chick.

Feather sexing chicks can be accomplished by crossing males that are homozygous for rapid feather growth or carry two rapid feather growth alleles ( k+/k+) with females that are hemizygous or carry only one slow feather growth allele ( K/_W).

The female parent contributes a dominant gene for slow feather growth (K) to all the male offspring while the female offspring will inherit only one rapid feather growth allele ( k+) from the father. This cross produces males that have slow feather growth (K/k+) and females that have rapid feather growth (k+/_W).


The following site provides an excellent example of how to tell the difference between a rapid feathering female (pullet) chick and a slow feathering male (cockerel) chick. You have to examine the feathers on the wings of the newly hatched chick. Wait until the down dries and examine the wing feathers.

http://animalsciences.missouri.edu/reprod/ReproTech/Feathersex/sld006.htm


The table below contains some of the birds that can be crossed to produce chicks that can be feather sexed.

Any of the males in the table, can be crossed with any of the females in the table to produce offspring that can be feather sexed. If you purchased your birds from a hatchery, check with the hatchery to see if the hatchery feather sexed the birds you purchased. If your stock was feather sexed, then the chickens cannot be used for feather sexing crosses.

 

[OhZark Biddies]

Some basic links:

Poultry Genetics for the Nonprofessional:
http://sellers.kippenjungle.nl/page0.html

Genetics of shank/feet color

Genetics of dark skin color

Genetics of feather color

table of chicken genes (including Feathered leg genes)

 

[Brahma Chicken5000]

Some basic links:

Poultry Genetics for the Nonprofessional:
http://sellers.kippenjungle.nl/page0.html

Genetics of shank/feet color

Genetics of dark skin color

Genetics of feather color

table of chicken genes (including Feathered leg genes)

Thank you.

 

[nicalandia]

I will be giving a presentation on chicken genetics to my mother’s science classes over spring break. I know the basic genetics of combs, egg color, cresting, Silkie feathering, Frizzle feathering, Naked Neck complete and codominance.
Would some of you genetic experts please shed some light on the following; shank color genetics, skin color genetics, feathered legs vs clean legs genetics, and the basics of plumage color genetics?
Thank you.

I will reply when I get the time, this is very extensive and just ran out of time, the good thing is that you have until spring break.