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#103375 - 04/14/12 08:46 PM Re: Chick down phenotypes and genotypes [Re: SilverSilkie]
M. J. Conley Offline
Coop Cleaner

Registered: 02/06/10
Posts: 183
Loc: Australia
I'm attempting to get hom E 'with no modifiers' (all other plumage 'genes' wildtype) to verify what hatchdown and adult plumage is, BUT aren't the wildtype alleles in the other plumage 'genes' affecting phenotype so it is impossible to get what say hom E phenotype is without modifications,
not feeling so clever, mark

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#103378 - 04/15/12 04:10 AM Re: Chick down phenotypes and genotypes [Re: M. J. Conley]
Htul Offline
Coop Keeper

Registered: 03/02/07
Posts: 495
Loc: Australia
No doubt they do affect each other: so really, all you can aim for is "E on an otherwise wild-type background" (which is what I thought you were after?)

The potential challenge though is if you have "non wildtype" other alleles that aren't phenotypically evident such as modifiers that don't modify the basic e+ appearance of brown leghorns, but might influence expression of E: eg. you crossing to get the E-like allele that you have onto the brown leghorn background that you have may look different to the same E-like allele crossed onto another strain of brown leghorn.

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#103379 - 04/15/12 04:39 AM Re: Chick down phenotypes and genotypes [Re: Htul]
M. J. Conley Offline
Coop Cleaner

Registered: 02/06/10
Posts: 183
Loc: Australia
Thanks Htul, i had to read that 2nd paragraph several times (English was my least best subject at school)..
Are you saying that other modifiers on Light Brown Leghorns that we don't know about yet would modify the E alleles effect on the phenotype?

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#103380 - 04/15/12 05:59 AM Re: Chick down phenotypes and genotypes [Re: M. J. Conley]
Htul Offline
Coop Keeper

Registered: 03/02/07
Posts: 495
Loc: Australia
Originally Posted By: M. J. Conley
...Are you saying that other modifiers on Light Brown Leghorns that we don't know about yet would modify the E alleles effect on the phenotype?


Potentially, yes - but not just "modifiers on Light Brown Leghorns": there could be lots of such modifiers that might act on non-wildtype alleles, that still have no apparent effect on wildtype. So, sure, we take it for granted that light brown leghorns (as a proxy for RJF) are "wildtype" - but how much so? We really oversimply it when we say "light brown leghorn have a "+" genotype except for w/w and Id/Id": surely that is not entirely correct - else why does a leghorn lay say 200+ eggs per year, whereas the RJF would be lucky to lay 20 in a year? (and can anybody claim, with absolute certainty, that such production traits have absolutely no pleiotropic effect on plumage genetics?)

For a related reason, I was inspired to create the following thread on An issue with the use of RJF as a wildtype standard which drew very little interest or comment (other than a lone comment by Kazjaps) - clearly nobody else views this as a potential problem.

Cheers,
htul

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#103382 - 04/15/12 04:45 PM Re: Chick down phenotypes and genotypes [Re: Htul]
M. J. Conley Offline
Coop Cleaner

Registered: 02/06/10
Posts: 183
Loc: Australia
Thanks Htul, yep, with you now. And I remember that previous thread, but reread it anyway, mark

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#103391 - 04/17/12 08:24 AM Re: Chick down phenotypes and genotypes [Re: M. J. Conley]
KazJaps Offline
Classroom Professor

Registered: 08/30/02
Posts: 2807
Loc: Australia
Considering there don't seem to be as many mutations/modifiers in other poultry species as with chickens, I thought it would be interesting looking at other species day-old chick down MC1R E locus mutations (ie less worries as to whether other mutations modifying E locus alleles).

eg, Turkeys MC1R - two mutations:
(photos from Feathersite and Porter's Rare Heritage Turkeys)
for comparison - wild-type:


Black


--------------
Black-winged Bronze


The last one is interesting in that it is a recessive eumelanising MC1R mutation. Usually MC1R dominant mutations increase eumelanin & recessives reduce eumelanin.

These two mutations have been sequenced:

Variability of the melanocortin 1 receptor (MC1R) gene explains the segregation of the bronze locus in turkey (Meleagris gallopavo).
Vidal O, Viñas J, Pla C.
Poult Sci. 2010 Aug;89(8):1599-602.
Full Paper

p.s. both of the above MC1R turkey mutation alleles are different mutations to chicken E, ER-Leghorn and ER-Fayoumi.

----------------------------
In the above journal paper they also mention the recessive eumelanising mutation in guinea fowl as another MC1R mutation, ie Purple:
(photos from Guinea fowl International website)

wild-type guinea fowl chick:


Royal Purple:


This recessive eumelanising MC1R mutation has been sequenced:

Melanism in guinea fowl (Numida meleagris) is associated with a deletion of Phenylalanine-256 in the MC1R gene.
Vidal O, Araguas RM, Fernández E, Heras S, Sanz N, Pla C.
Anim Genet. 2010 Dec;41(6):656-8.
abstract

-------------------
Interesting how all these MC1R eumelanising mutations add white to day-old chick down. The turkey black mutation is very similar in phenotype to the chicken E allele, ie down is white ventrally & face, plus wing flights, and the rest black. Plus epidermal pigment on the shanks.

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#103748 - 05/13/12 01:06 AM Re: Chick down phenotypes and genotypes [Re: KazJaps]
Henk69 Offline
Moderator
Classroom Professor

Registered: 02/13/06
Posts: 3208
Loc: Netherlands
These are a mix of dun silver duckwing males and dun gold duckwing female chicks:



The females are S-Id/-, the males s+-Id/S-id+
Father: gold duckwing modern english game bantam with yellow legs
Mothers: khaki silver duckwing dutch bantam

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#104282 - 06/17/12 08:46 PM Re: Chick down phenotypes and genotypes [Re: Henk69]
Smooth Mule Offline
Coop Keeper

Registered: 02/13/10
Posts: 637
Loc: Missouri


Edited by Henk69 (06/17/12 11:19 PM)

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#104305 - 06/19/12 05:24 PM Re: Chick down phenotypes and genotypes [Re: Smooth Mule]
Wieslaw Offline
Moderator
Classroom Professor

Registered: 09/18/09
Posts: 3769
Loc: Denmark
Yes.

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#104425 - 06/27/12 09:21 PM Re: Chick down phenotypes and genotypes [Re: Wieslaw]
Smooth Mule Offline
Coop Keeper

Registered: 02/13/10
Posts: 637
Loc: Missouri
Chocolate (recessive/sex linked).....this is the beginning of my LF Chocolate Araucana project





Edited by Smooth Mule (06/27/12 09:31 PM)

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