Crested Cream Legbar Genotype vs. Phenotype

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Laingcroft

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8 Years
Nov 22, 2011
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Because we don't have enough threads discussing the "standard", "colors" and "genotype" I thought I'd add another :)

Seriously, I thought it might be easier to have this discussion in one place instead of trying to figure out what statement or picture on the subject was posted on which one of the other threads.

Has anyone come up with the suspected genotype for the Crested Cream Legbar yet? Did Dr. Punnett jot it down in any of his literature? I didn't see anything in the club history.

I also think we need to be a little more consistent on terminology -- not cream does not necessarily equal gold.

Based on the SOP we're working with, I suspect the base for the CCL is wild type duckwing expressed as 'e+' If we take away the barring pattern and any other enhancers, I believe we have a base color of black breast, body, primaries, tails/sickles with orange-red hackle with some black shafting that varies between heavy and light and an orange-red saddle. The hens are "brown" with salmon breasts. Chicks are chipmunk striped.

Next we have to decide if we are working with autosomal red (AR) or sex linked red i.e. s+ gold. That's a bit trickier. I've been studying Sigrid VanDort's book on genetics, but it seems to have a conflict re: autosomal red. In one case she states that AR is part of the e+ wild pattern and that silver does not affect it then she shows the silver duckwing based on e+ without the AR (ar) Anyone able clarify this? Either it is or is not part of the e+ and either S can or cannot affect the AR based salmon breast on the hen. I'm still confused here. The fact that the standard allows for some chestnut on the back leads me to believe there is some AR in this breed which is predominantly suppressed by other modifiers.

Dr. Punnett was working on auto sexing characteristics and using sex-linked barring. It appears from the CCL history that he was also using the gold gene as part of his sex-link studies. It also appears that he was crossing a multitude of varieties in his attempts to fix the autosexing characteristics. So it could be possible that we ended up with a very similar phenotype of Silver Duckwing with salmon breasted females. Males that are S/S and AR/ar can also appear very similar to males that are S/s+

When Dr. Punnett added that lemony/cream Chilean bird to the mix, it was called cream but it could have been the Dilution gene 'Di' a straightforward dominant. It is the red modifier that creates a variety of colors from pale red through buff and lemon. Interestingly enough the dilution gene also mutes the stripes on the chipmunk down color, as our male chicks are muted.

Cream or Inhibitor of gold - ig - is a recessive and needs a double dose, but there has to be a gold base to inhibit, which would eliminate Silver males as the history indicates was done. On the other hand, heterozygous silver males could have had straw/red leakage, especially in the presence of autosomal red -- phenotype S/s Ar+/ar or Ar+/Ar+ This could result in those gold hens.

Then we have Cb or the champagne gene which does the same thing as ig.

Given that the breed was developed early in the 20th century and breeders in the U.K. have been working with it for awhile, what started as a pretty mixed up phenotype could have evolved to a preference for the silver/light phenotype and possibly a silver genotype with the original genotype gold based birds being eliminated.

Just to add to the confusion, the Dutch Cream chicken phenotype is e+/e+ s+/s+ Ar+/Ar+ Di/Di ig/ig Bl/Bl

I would be interested to hear other thoughts and opinions on any of these modifiers and/or genotype possibilities. I would also love to know if the breed's genotype has already been determined. It's hard to work toward something when you're not 100% certain what you are working with.
 
Crested Cream legbar (CCL) are wild type (gold duck wing), sex linked barred, and carry the cream gene. They also carry a form of autosomal red.

Autosomal red is not an actual gene but is a term for red not due to the gold allele. Hutt coined the term autosomal red. You should not use a gene symbol to represent the gene.

Autosomal red is not due to the wild type allele and is expressed by another gene or genes. I have produced silver wheaten female birds that express autosomal red. see picture below. It is also expressed in the salmon faverolle which is silver wheaten. Autosomal red is or are hypostatic to the cream gene or in other words is not diluted by the cream gene. This is why the CCL have the chestnut color in their plumage. Notice the chestnut color in the picture of my bird.

200x200px-ZC-a1bcd271_13371_100_3227.jpeg


If autosomal red is added to a silver duck wing's genotype you get a golden duck wing. Golden duck wing could also be heterozygous at the silver locus.

The diluted (muted) down of the CCL male chick is not due to the cream gene; this characteristic is caused by two doses of the barring gene.

Silver does not effect the salmon breast on a wild type female. To the best of my knowledge- autosomal red does not effect the salmon breast.

CCL are gold but the cream gene will dilute the red pigment. The dilution of red can vary. Taylor's work with cream indicated that some gold males were diluted to the point that they appeared to be silver males. This is why CCL males have very diluted hackles. The barring genes also dilute the hackles.


CCL genotype is e+/e+, s+/s+, ig/ig, B/B or B/w, w/w ( yellow skin), Id/Id or Id/w ( dermal melanin inhibitor), Cr/Cr (crest), genes for white ear lobes, O/O (blue egg shell), there are other genes that deal with brown egg shell color- one is an inhibitor of brown egg shell color they may carry the gene, rapid feathering k+/k+ or k+/_W, genes for reddish bay eye color. They also carry autosomal red.

Any one interested in egg shell color can read the following paper. It is complicated.
http://www.maranschickenclubusa.com/files/eggreview.pdf



Tim
 
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Good idea @Laingcroft . Not sure how many people will jump over here because of the number of Cream Legbar threads but I think this will be a nice place for discussions.
 
Thank you for starting the thread Laingcroft.

Thanks, Tim, for the explanation.

For Punnett's other legbars, the gold and silver, would the ig/ig not be present and the O/O and Cr/Cr be absent as well. Otherwise the sequence would be the same as for the Cream Legbar with the exception of genetics respectively for gold and silver?
 
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I would also ADD that it appears that they have some sort of melanizers, like the one that forms stippling on the males hackles of the Cream Gilpartridge leghorns of holland, but this stippling extends tot he saddle and wing secondaries and along tot he shoulders and creasts
 
on the Phenotyp vs Genotype debate.. one can have a Cream Looking bird, heck even a Rich colored Cream colored bird, resembling cream with some red enhancers. with Silver (S/S) instead of Gold. and instead of cream(diluting the gold) we would have enhancers(Autosomal red, Mahogany) to enhance the Silver... example: Salmon Faverolle, the male is a Duckwing type of bird(not the female) he looks golden but is infact red enhanced Silver..
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