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Post by tiffin on Nov 29, 2008 11:56:46 GMT -5
You have to be in "reply", not "quick reply." Make sure your cursor is in Message then go up and click on the smiley you want; it will pop in the Message area, not as a smiley that you can see there but the symbol for a smiley. By the way, Carol I sent you a PM. Adrienne
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Post by cddexter on Nov 29, 2008 12:09:11 GMT -5
ah!!! ;D ;D ;D ;D thanks. me.
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Post by copperhead on Jan 2, 2009 13:57:35 GMT -5
I have a black bull that has a lot of dun in his background and Ms Fermoy too. So far I have got two dun calves from him and their black momma's. One of them is polled, short and dun, he's gonna be such a stud, haa ha......... My problem is that I didn't do a good enough color background check, I got him because I wanted black, not dun. Oh well, when I make a plan, God laughs...... P.J.
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Post by rhonda on Jan 4, 2009 18:48:18 GMT -5
I know what will happen---I bred 2 duns to get dun and I will get black!!!
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Post by liz on Jan 5, 2009 16:11:52 GMT -5
That isn't possible Rhonda, dun is a mutation to the black gene that only works when the animal is homozygous for the mutation. Each dun parent would pass the calf the gene to cause dun and so it would be homozygous and be dun itself. The only other possiblity of a dun to dun x is that they both carry the red gene and pass that to the calf and then the calf would be red. Liz
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Post by rhonda on Jan 5, 2009 19:02:51 GMT -5
Thanks Liz!!! That makes me feel better---someday I'll know this stuff???
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Post by cddexter on Nov 23, 2010 16:29:30 GMT -5
fyi, somewhere around here I mentioned the CDCA colour article on their website was wrong because it referred to dun as a diluter I've spoken with their web master, and emailed him the correct info. He, in turn, has passed it on to the author (liz). She has gone to Sheila Schmutz for the exact correct wording, and has changed their article to rectify the error. The article now refers to brown, but combines it with dun ('dun brown' as though it was one colour (which it is, I suppose, just different names). c.
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Post by onthebit on Nov 25, 2010 12:11:32 GMT -5
Carol, Can you please phone the webmaster at UC Davis and have them correct their web site too? "Dexter Dun The Dun coat color in Dexter cattle is a dilution of black pigment (eumelanin) caused by a recessive mutation in the gene tyrosinase related protein 1 (TYRP1), also known as the Brown locus. The hair color is diluted to shades of dark brown to golden. Red pigment is not diluted by this mutation. A genetic test specific for the Dexter Dun mutation is available from VGL." www.vgl.ucdavis.edu/services/coatcolordexter.phpThanks!
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Post by cddexter on Nov 25, 2010 18:09:38 GMT -5
Probably better i get john potter to do it. His name is on the paper, and he has the technical credibility. Thanks for pointing this out. c.
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Post by cddexter on Nov 26, 2010 13:44:34 GMT -5
ah, more info. Just spent some time chatting with John Potter, who still has the orginal papers by sheila on both dexter and dog brown, and have an update info for y'all. Just a reminder, dexter brown is also the same gene as dog and mice brown, but completely different from any of the not black, not red, cattle colors.
There are two different uses of the term dilute. The common parlance in cattle is a dominant gene that changes the coat color. That's not what we have. Ours is a unique, one-of-a-kind, special use 'dilute', and has to be used sparingly, or not at all, or with a very clear and definite qualifier. Most people aren't all that pedantic, so it's best to take the easy way out and just use brown for Dexter 'dun', and keep away from the term dilute completely, as to just about everyone, it's misleading.
dexter brown is sort of, kind of, depending on where you are coming from, a diluter in the general sense that black is changed, but not a diluter in the specific sense that our dexter brown is completely different from dilute genes in all other cattle breeds. So, while we've always been told to refer to the dexter dun as a brown gene and not a dilute, in biochemical terms, it can be termed such. To stop confusion, we should be calling our distinct, found only in Dexters, 'dun' gene brown, not dilute. clear?
snurfle. chortle. haha.
What this all really means is:
In cattle, dilute colors are caused by separate dilute genes which are DOMINANT to the base coat color. Some cattle have TWO different dilute genes, both dominant (because all diluters in cattle are dominant, remember?) causing a double bleaching effect. Think Simmental, Blonde d'Aquitaine, Galloway, Highland, etc. These are true 'dilute' genes, caused by a dominant gene affecting all the alleles at the base coat color locus. Thus, any time you refer to a dilute gene when talking about cattle, you will always get the assumption there is a dominant dilute gene involved, and that all alleles can be affected. This is not so in our case.
Dexter brown is NOT a dominant gene. It is a RECESSIVE gene. Thus, our breed has the only known base color locus modifier that is recessive, and we've been told not to call it a dilute gene (because this will confuse the heck out of anyone who has color knowledge because it flies in the face of everything they know--sheila's a good case in point: it took a long time to convince her to believe we had a recessive modifier and to check it out--and she was receptive! Just think how much more difficult to someone NOT receptive!!).
In biochemical terms, anything that changes the color of the base locus can be deemed a 'diluter' gene, but because all diluter genes in cattle are dominant, except ours, and no other cattle breed has been found to have a brown gene, like ours, we have always been told not to use the term dilute when referring to our 'dun', but to refer to it as brown. This distinguishes our brown from the usual, normal, everyday use of the term 'dilute' when referring to cattle. In hindsight, this is probably because it's easier for a bunch of non-scientists to 'get', rather than the longer detailed explanation that MUST, to be technically correct, include the terms dominant and recessive, to distinguish it for boffins so they aren't confused.
So, UCDavis is technically right, as brown does change the color of black, and thus TYRP1 can be deemed a form of dilute gene. Please remember the original article was written in scientific terms for scientific peers, not in ordinary street language for the average livestock owner with a different education level. If you read Sheila's web articles, written for laymen, she does not use the term 'dilute' when referring to dun cattle.
However, because our 'dilute' gene is unique to our breed, and completely different from any other cattle dilute gene, both in location, type and effect, for everyday use, and for non-scientists, and the average livestock person, including Dexter owners, and the like, as well as for scientists but without any qualifiers, our Dexter brown is distinct from 'dilute' genes, and thus needs to be defined in a distinct way. We are advised to refer to Dexter 'dun' as a brown gene and not a dilute gene to avoid confusion.
PS Weimaraner dogs are DILUTE BROWN. If they weren't dilute, they'd be the same color as a dun dexter. Go figure that one. I want to try for a weimaraner dexter ;D.
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Post by onthebit on Nov 26, 2010 14:41:16 GMT -5
"he CDCA has some info as well, but their coat colour genetics is not quite right. I keep meaning to call their webmaster and get it fixed.... Dexter 'dun' is NOT a diluter gene, it's a true 'brown' gene at another locus. Other than that, the info is okay." Read more: dextercattle.proboards.com/index.cgi?board=intro&action=display&thread=1313&page=2#ixzz16Q2eQftgI suppose you now owe the CDCA and Liz an apology, and it might be prudent to call the CDCA webmaster aka President to apologize for wasting so much of his time. What does crow taste like anyways?
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Post by cddexter on Nov 26, 2010 15:13:44 GMT -5
my goodness, charlotte, what a bitter response. Is this you speaking, or are you fronting for someone else?
If you and everyone else reading this, and Liz's article, are bone fide degreed scientists, and understand the difference between common parlance and specialized terms, I apologise. However, in layman's terms, this is not considered a dilute gene. My comments stand.
Mention 'dilute' color genes and you will be assumed to be speaking of a dominant gene. Mention brown, and you will either get questions, or the knowledge it's recessive.
Sheila reviewed the paper presented to the 2002 Congress which dealt with Dexter 'brown', and found no fault with it. I can only bow to her superior knowledge. C.
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Post by copperhead on Nov 26, 2010 19:37:25 GMT -5
Carol, I really appreciate your knowledge in this matter, thank you for sharing. P,J,
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Post by liz on Nov 26, 2010 20:59:39 GMT -5
yes I agree with Copperhead, thanks Carol for explaining this to us ;D What I am understanding is that 'dilute' is 'dilute' only if you are are a scientist? ;D Too funny! Liz
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Post by cddexter on Nov 26, 2010 22:47:15 GMT -5
Hi liz: no.
To a scientist, anything that modifies a color down is a diluter. But a scientist knows to include the terms recessive and brown, so our 'dun' is not confused with the usual dominant dilute gene they expect to find in cattle. That inclusion is not something your average layman would bother with, or necessarily understand why it was required to be part of the definition.
'Dilute' genes in cattle, in the everyday scheme of things have known, accepted, standard properties. Under those conditions, a standard 'dilute' black Dexter would be grey, like Murray Grey cattle, because dilute black is grey. MG's are in no way the same color as dun Dexters, which are brown. The brown gene is different from a regular 'dilute' gene, and so needs to be distinguished. That distinction is the difference between calling TYRP1 a dilute gene, and calling it brown.
If you check Sheila's color website, you'll see that what she writes for laymen is not at all the same thing she writes when publishing a scientific paper to be read by peers. Cheers, c.
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