high school biology book question

[clintwilson59]

ok so in biology class the other day we were talking about codominant genes and punnet squares. well one of the examples was they bred a domonant white chicken to a black domonant chicken and it would result in checkered off spring and they showed picture of a dominique chicken. Has anyone seen this before because im pretty positive dominiques are a breed and didnt come from a clack chicken and a white chicken. i just found this and thought it was intresting.

 

[BarkerChickens]

You are correct. Dominique's are breed and they are barred, another dominant gene. They are NOT a black chicken/white chicken cross.

 

[Illia]

I've heard someone else say the same thing - That their science teacher told 'em black and white chickens make checkered chickens. . .

Black and dominant White make white.

Barring is indeed a gene by itself, and not related to the others at all.

 

[SunnyChic]

Here's what I found in my old book, Poultry Breeding, by Morely A. Jull (copyright 1932):
"When a White Leghorn (its plumage is dominant white), either male or female, is mated with a colored bird, such as Black Minorca, the F1 chicks are white, except that many of the chicks may have black spots in the down. These chicks with the black ticking usually develop into adults having some black in their plumage, the partially black feathers exhibiting barring..."

So they would be white, but they might have some partially black feathers that would be barred. You're right, they wouldn't be barred all over.

 

[Chris09]

This quote is from tadkerson on 11/24/2009 and was posted at this link by Sonoran Silkies
https://www.backyardchickens.com/forum/viewtopic.php?id=379322 :

Dominant

Dominant white is different because it tries to switch off the chemical pathways but does not do a very good job. It is good at switching off the pathway that makes black but has a hard time turning off the chemical pathway that makes red. This causes some of the red pigment to leak through the white.
Sometimes the dominant white gene only switches off the black for a short time then allows the black to switch back on so you do get some black pigment in the feathers. In order to get rid of the black completely, breeders will add additional genes to a bird that also turn off the chemical pathway that makes black pigment.
In order to keep dominant white birds white, breeders want the genes in the bird that make black pigment and not red pigment. You could say that the dominant white bird is black under the white. The bird has the genes to make black feathers but the dominant white gene or genes like barring and silver turn off the chemical pathways that make the black pigments.
You can say recessive white genes really do not need help from other genes to make a bird white but the dominant white gene needs help from genes like silver and barring.

Chris​

 

[Moabite]

My birds don't wear jeans, but it kinda looks like they have pantaloons on though.

 

[blackdotte]

The mating of a dominant White chicken to "a dominant Black ?" chicken will not give checkered chickens under normal circumstances.
Firstly there is no such thing as "a dominant Black " chicken. Black can only be produced by a combination of genes.
The closest thing to a " checkered chicken" would be an Exchequer or Mottled bird, to get this both parents must be carriers as it is a recessive gene.
I think your teacher was using this as an example, he/she would have been better staying with Mendel's standard example of White,Red & Pink Pea flowers.

 

[Kev]

In my own biology class, "Andalusian chickens" was used as the poultry example. Was not so perfect either as they had the splashes described as "white"- even had an illustration of a completely white chicken. I suspect this little mistake why it's not so uncommon to come across folks saying to get blue chickens, you need to cross a black with a white chicken..

One cool example using chickens are comb types. It was fun seeing the results of pea x rose comb cross (walnut).

 

[Sonoran Silkies]

Awhile back there was a discussion either here or at The-Coop on whether chickens have any co-dominant genes. The consensus was that there are no co-dominant colour genes in chickens, but that comb genes can probably be considered co-dominant.

I agree that sticking with Mendel's actual experiments would have been better.

 

[tadkerson]

Quote:
Burn the book. That is rediculus- whoever wrote the book was lazy and did not do the neccesary research. People can write any old peice of trash and have it published.

The best example of codominance is blood types in humans. In this case, a person can have two different types of antigens (proteins) on the surface of a red blood cell. A person that has AB blood has two different kinds of antigens on the blood cells which were made made by two different alleles. Allele A makes the A antigen and allele B makes the B antigen.

In codominance, both alleles in a gene pair must produce a product that effects the phenotype of an organism. This can occur in a few different ways so what I have stated is a simple way of looking at the process.


A person can produce barred chickens if they cross a white chicken with a black chicken. If person crosses a male chicken that is recessive white (and this same bird carries hypostatic barring and black ) with a black female bird, all of the chicks will be black and barred.

Male genotype c/c E/E Ml/Ml B/B X female C/C E/E Ml/Ml b+/_ = all barred chicks

This sort of thing occured in the late 1800s and early 1900s (and still does today), so people thought barring was an interaction of the white and black phenotypes. If you can find it, read Raymond Pearl's "Notes On The History Of Barred Breeds of Poultry".



Tim