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Post by Olga on Jul 1, 2008 11:26:32 GMT -5
Anyone out there curious about the possible color outcome of a breeding between a particular cow and bull? We would need a genetic color profile on both (preferably) but in some instances for one of the animals would suffice. I can't use any of mine, they are all black and I won't spend money on testing them for color unless I see a colored calf on the ground. But I do know a few things about them none-the-less: - a black heifer out of our black bull and black cow (now deceased) delivered a dun calf when bred to a dun bull - which means the heifer carries dun, which means our bull might carry dun (his sire was dun, by the way);
- our cow Erin had a dun calf right before we bought her, so she carries dun also
So, one of these days Erin might have a dun calf and then I'll know for sure that Sam carries dun also. |
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Post by marion on Jul 1, 2008 13:26:53 GMT -5
Hi Olga, If your bull had a dun sire or dam, he definitely would carry dun ;D ..marion
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Post by Olga on Jul 1, 2008 17:50:58 GMT -5
Oh, yeah... I'm still trying to figure this stuff out... which is why I'm starting this color discussion, so there would be less confusion.
To explain why my bull must carry dun since his sire was dun, here is a table for the brown locus (black/dun alternative):
Black is B/B (black/black) or B/b (black/dun)
Dun is b/b (dun/dun)
If my bull's sire was dun, then he'd be b/b, in which case he'd have nothing other than the b from the brown locus to pass onto his offspring.
Common sense, but I just never set down to think about it before today, thanks Marion
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Post by liz on Jul 1, 2008 19:08:04 GMT -5
Hi Olga; Maybe we are both saying the same thing and I am misunderstanding but .... Dun in Dexters is located on a different set of alleles than red/black and actually requires the animal to have a black gene in order for the dun to be created. In other words, dun colour is a mutation of the black gene which starts and then if the animal is homozygous (inherited the dun gene from both parents) then this prevents the black gene from completing and results in the colour 'dun'. So the reason that red breeds true, even if that animal is homozygous 'dun' is that the black gene cannot be present on an animal that presents red but it must be present on an animal that presents dun. This is also why red x dun usually produces black because a dun animal always carries black and even if it carries red, there is still a 50% chance that it will pass the black gene and since as you pointed out, red is recessive to black, the offspring would appear black but carry dun. Clear as mud!  So in the case of a dun animal breeding another black or red, there is no question that the animal will pass dun to the offspring but will also pass black or red. Liz |
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Post by Olga on Jul 1, 2008 23:45:09 GMT -5
Gee, Liz, you just had to go there ;D Right... that just went right over my head, by the way. But, from the "Basic Concepts of Dexter color Genetics" what I do understand is that there are two pairs of genes that are located on separate chromosomes. So, from page 89 of the 2007 ADCA Membership Directory, here are these pairs: Pair #1 has to do with Black (dominant) vs. two versions of red (alternatives to each other, both recessive to Black): red 1 and red 2. A black animal can have: - Black/Black
- Black/red 1
- Black/red 2
And a red animal can have: - red 1/red 1
- red 1/red 2
- red 2/red 2
Pair #2 has to do with Black (dominant) vs. dun (a brown mutation, recessive to black). A Black animal can be: And a dun animal has to be: This brings us to the Combination Genotypes for Colors table. Possible Genotypes of Black Animals: - Black/Black Black/Black
- Black/Black Black/dun
- Black/red 1 Black/Black
- Black/red 1 Black/dun
- Black/red 2 Black/Black
- Black/red 2 Black/dun
Possible Genotypes of Red Animals- red 1/red 1 Black/Black
- red 1/red 1 Black/dun
- red 1/red 1 dun/dun
- red 1/red 2 Black/Black
- red 1/red 2 Black/dun
- red 1/red 2 dun/dun
- red 2/red 2 Black/Black
- red 2/red 2 Black/dun
- red 2/red 2 dun/dun
Possible Genotypes of Dun Animals- Black/Black dun/dun
- Black/red 1 dun/dun
- Black/red 2 dun/dun
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Post by liz on Jul 2, 2008 7:03:18 GMT -5
Just as I thought, we are both pretty much saying the same thing! I had never been able to 'grasp' the tables of possible colour combinations, was never good at math either , but when I read the article on the dexinfo site, " "TYRP1 is Associated With Dun Coat Colour in Dexter Cattle or How Now Brown Cow?" " I finally 'got' it. I had thought that because Dexters were either black, red or dun that all three colour genes were located in the same location. Then it followed that because dun is recessive to black the presense of 'dun' meant the absence of 'black' But reading the article, I finally understood that the two colours were located on completely different locus' (loci?  ) and that while one dun allele is recessive to black two duns are more powerful than black. But that black must be present at the other location in order for its appearance to be dun because the gene that dexters carry works by diluting black. This is why a red Dexter might be homozygous for dun, dd, but not express it because the dexter dun (TRP1) gene 'needs' black and doesn't affect red. Now I also understand that while a dexter always has either black/ black or black/red or red/red (and wild) at one location it doesn't necessarily have anything at the TRP1 location. As Gene says, the science is pretty 'cool'! |
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Post by Steve on Jul 2, 2008 9:05:15 GMT -5
My head is starting to hurt.
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Post by Wags on Jul 2, 2008 11:37:04 GMT -5
My head is starting to hurt. Mine too!  I thought Dexter's were only solid colors, but then I read they could have spots or bridling? Anyone ever seen one with spots or bridling? That would be very cool!  I have Nigerian Dwarf goats too and love the crazy color mixes they produce, it was one of the factors I considered when I got them. |
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Post by legendrockranch on Jul 2, 2008 21:35:49 GMT -5
If both dun genes b/b are present in an E+/E+ animal, then the animal will be red with a tan muzzle. Genebo, where did you get this information? The two links you provide did not mention this, especially the two dun b/b genes as being present to show a tan muzzle ring on a red E+/E+ animal. I don't believe this to be true, but always wanting to learn more. |
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Post by legendrockranch on Jul 3, 2008 13:22:39 GMT -5
Genebo,
From what I've noticed within my own herd is that the tan muzzle ring is more prominent in bulls as apposed to cows.
My red bull who is E+/E+ does not carry dun, in his youth he did have a tan muzzle ring. As he aged it slowly started disappearing.
He is now a little over 4 years old and does NOT show a muzzle ring at all.
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Post by liz on Jul 4, 2008 14:03:16 GMT -5
Gene I think that Pilgrim would have been 'dun' not red because Cluny didn't carry red. Liz
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Post by legendrockranch on Jul 4, 2008 20:55:16 GMT -5
Genebo,
My bull shows no brindling or spotting. I tried to go out and take pictures today, but most of the time he was laying down with his girls. He does have Outlaw and and Wee Gaelic Ms. Femoy in his backround.
You might want to contact John Potter, he is a guru on Dexter genetics. He also was one of the co-authors on a link you posted earlier.
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So in the case of a dun animal breeding another black or red, there is no question that the animal will pass dun to the offspring but will also pass black or red. Liz
) and that while one dun allele is recessive to black two duns are more powerful than black. But that black must be present at the other location in order for its appearance to be dun because the gene that dexters carry works by diluting black. This is why a red Dexter might be homozygous for dun, dd, but not express it because the dexter dun (TRP1) gene 'needs' black and doesn't affect red. Now I also understand that while a dexter always has either black/ black or black/red or red/red (and wild) at one location it doesn't necessarily have anything at the TRP1 location. As Gene says, the science is pretty 'cool'!
