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Announcement re Roan/Tobiano's!

Thought I would post this interesting announcement on the Animal Genetics site, sorry if this has already been discussed. So if we understand this right, if you have a tobiano + roan horse it is in a sense homozygous for a white pattern and will never breed a solid foal? Like a Pearl and Cream carrier can not throw both but will always throw one or the other. Also opens up a debate re roans.. should they be seen and classed the same as Paints?? [color=#BF0000]RECENT UPGRADES 6/10/10: We have changed the calculator to take into account that Roan and Tobiano are mutations of the KIT gene found on horse chromosome 3 and thus will not occur on the same branch of a horses chromosome pair. This means that a horse that carries both Tobiano and Roan can only be heterozygous for each gene and will pass one or the other to its offspring and not both or none. This is also the case for Sabino1 and the known Dominant White mutations which are also mutations of the KIT gene. We have not yet made the change for Tobiano/Sabino or Roan/Sabino combinations but plan to in the near future.[/color]

Third Peppermint Tue, 06/22/2010 - 16:09

Congratulations horsegen! I'm glad you're back and I hope the baby is doing faaaaabulous.

Thanks for commenting on this whole KIT gene connection crossover thing. I had never heard that roan and tobiano were in the same place and exist on the same chromosome so I was pretty suspicious of the whole thing. I didn't see any links to journal articles and I get rather skeptical when someone I don't know says something that sounds so strange to me. It's a little more comforting to hear it from someone that I trust as a source! Is there a journal article published about this yet? I'd really like to read it when I magic up some free time.

Speaking of KIT being filled with mutations... I noticed that humans get some spontaneous mutations that cause white markings (mainly face and belly?) and it seems to happen quite often. There's actually a facebook page for people with piebaldism and I think the main phenotype change is a white patch of hair right on the hairline of the forehead. I had no idea that was a KIT mutation, but apparently people can be born with it randomly, and then it can be inherited. My favorite are the loud white people, especially with a very dark complexion.

Basically, what I'm wondering, is if KIT mutates so easily, could it be possible that all white markings are random mutations of KIT (or random mutations passed down) and therefore there are a bazillion? And with the test for tobiano: is it 100% one particular change or could there be multiple mutations of the sameish region that are slightly different and result in slightly different phenotypes that test the same?

horsegen Tue, 06/22/2010 - 18:14

Thanks, everyone! I have a bunch of pics, but need to get them hosted on the internet somewhere first, and...eh. Too much trouble these days. Trust me, though...he's totally adorable. ;-)

[quote]Is there a journal article published about this yet? I'd really like to read it when I magic up some free time.[/quote]

Well, yes and no. There was a journal article published some years ago when a mutation causing the roan phenotype in Belgian horses was found in KIT. I don't have it with me at the moment (maternity leave) but I'm sure you could find in in PubMed. Unfortunately, that mutation is NOT the same mutation that causes roan in other breeds...it seems to be specific to Belgians. So THAT's published. Our lab has been working on roan on and off for many years. The strong linkage of roan to KIT is common knowledge at this point, but we haven't published it...we've always been waiting to find the actual mutation. We had a master's student do a bunch of work on roan and KIT a couple of years ago, and that is the work that led to the development of the roan haplotype test that UC Davis now offers. But even with all the linkage data and a whole bunch of sequencing, we haven't found exactly what is causing roan.

[quote]Basically, what I'm wondering, is if KIT mutates so easily, could it be possible that all white markings are random mutations of KIT (or random mutations passed down) and therefore there are a bazillion?[/quote]

Yes. In fact, a huge percentage of white spotting in many domesticated species is due to KIT. It is THE gene of choice for creating white markings! Now, it's not responsible for all of them...we looked at it when we were trying to find splash and splash is definitely NOT caused by KIT. But there are other genes out there that cause white spotting patterns.

[quote]And with the test for tobiano: is it 100% one particular change or could there be multiple mutations of the sameish region that are slightly different and result in slightly different phenotypes that test the same?[/quote]

We have never identified a phenotypically tobiano horse that did not have the very particular chromosomal rearrangement identified by Samantha Brooks. So my answer is, I don't think so...but anything is possible. I'd never say that there absolutely couldn't be multiple mutations causing tobiano, just that we haven't found one yet.

accphotography Tue, 06/22/2010 - 20:02

[quote="Ammit"]According to UC Davis nope. :roll:

Honestly I am not inclined to take none substantiated facts from you as truths. Nothing personal but I have seen no reason to believe your reports on data are to be trusted. You can continue to try and pick holes at things over and over all you want, but personally I will stick with the accepted science. Feel free to believe what ever you want but just trying to pick holes in things, for the sake of it, is starting get petty. You where confused about crossing over between tobi and roan. It is ok. Move on.[/quote]

I've got the proof. Would you like to see it? It is glaringly apparent just by looking at the family what is going on. It's not petty, it's a simple fact.

[quote="Ammit"]
And I was not going to mention this to save face for acc but what the heck. The owner of that website said she had never spoken to you in her life. ;-) ymwhisle
[/quote]

Wow... you are something. Apparently the owner is confused. I have PROOF in WRITING that we've been in contact... but I'm sure you'd find a way to say I faked that as well.

Danni Tue, 06/22/2010 - 20:44

[quote="Ammit"]Obviously this is not a place where I am going to fit in. Just not the atmosphere of real study of science I was hoping to find, but not every site is for everyone, and a site that promotes what I have seen is not for me. I harbor no hard feelings to the site admin and wish her the best. So many cooks can not survive in one kitchen. I wish you the best of luck.

Best make you color calculator a good one, mine is already mostly functional, and I look forward to seeing them compete. :-D :lol:

And I was not going to mention this to save face for acc but what the heck. The owner of that website said she had never spoken to you in her life. ;-) ymwhisle

Chow![/quote]

Ok I know I should stay out of this.... but anyway..!

Ammit I'm not sure if you are still around to read this, but I'm not exactly sure what has happened here :? You obviously know what you are talking about, but how do you think a lot of the knowledge you have today came about. Not just the scientific research, that would have come after intelligent people noticed patterns in different colour inheritance. Enough so that scientific theories could be made. Scientists can now test for different colours etc.. But we don't know everything yet. Some things are still theories, breeders observations are still very valuable. Intelligent people with good background colour knowledge making observations are even more valuable. More patterns start to be noticed and this should help the scientists?

If a scientific theory comes out, and someone else says, well I've seen an exception to that. I find that sort of information very valuable. Maybe those exceptions turnout to be not what they seemed, but sometimes they might help us to better understand how something works.

What I love about this group is that with so many people contributing, with different viewpoints from different breeds, it should support and help scientific research? You seem to be cranky that you have been questioned? I’m surprised at your attitude and automatically disregarding anything that doesn’t fit with what you know. I think one of the best things on this list is that many people have an open mind and try and work out the “why”. Even if it’s out of the norm. Personally I wouldn’t think much of a scientist that disregarded everything that didn’t fit within their theory.

It would be awesome if you can fit in here and help people like me better understand your side of it, but we are a group of people with different things to offer. Try and respect that too.
Cheers

Danni

lillith Wed, 06/23/2010 - 04:53

Sorry if I offended anyone there, I was trying to understand things, my questions weren't attacks they were me trying to learn.

Third Peppermint, my info on sabino came from the DW website with all the DW mutations explained similarly, they gave me the idea for the tables which seemed like a good way to put it all for my understanding abilities. Nice and simples.

Brooks S.A. and Bailey E. Exon skipping in the KIT gene causes a Sabino spotting pattern in horses. Mammalian Genome 16:893-902, 2005.

http://greenrage.wordpress.com/2008/02/…" onclick="window.open(this.href);return false;

S.A. Brooks, T.L. Lear, D.L. Adelson, E. Bailey. A chromosome inversion near the KIT gene and the Tobiano spotting pattern in horses. Cytogenet Genome Research 119:225-230 (2007)

The information about roan is may have come from the DW site as well, I didn't put down a ref for it on my table :sigh: :hammer I will try to find it again.

lillith Thu, 06/24/2010 - 05:09

Thanks everyone, I hope my stuff helps. Once I have finished my tables I'd be happy to email them to people. :)

I just have to twist things arround untill they fit in my head.

lillith Fri, 06/25/2010 - 02:57

Sounds good. I wish mine had been lol.

I am actualy ok at book learning I just have to re-write it in my own way to get it in, and doing diagrams/tables helps me condense the masses of words down to the essential message to learn it. Normally I can just read stuff and it goes straight in but this is a bit complicated. I have to jump otherwise it goes over my head. :bounce

JNFerrigno Fri, 06/25/2010 - 04:44

....DANG. I think I'm in love with you people.

Pardon my little moment of immature bliss, but I'm not sure you can understand how excited I am to find a community of people who's knowledge on equine color is just spewing from every orifice of their body. I thought this was a community of hobbyists, but I'm really excited to see there are actual lab-rats! So making a random post right now to basically save my place in this thread so I can refer to it when it's not 5:30 in the morning and I'm running out of coffee. Be forewarned, I think I'm going to be so active on here y'all gonna get really sick of me LOL. Horses and Science have been a passion or mine since I can remember, the end result is me being an insane hobbyist and future high school science teacher (._. I know, don't ask).

Ammit, if you are still lurking, I'd love to get in contact you about that color calculator you mentioned was in the works.

The rest of you, enjoy your morning, I'm going to DD's for my caffeine IV drip.

JNFerrigno Fri, 06/25/2010 - 05:36

[quote="accphotography"]This site has a pretty nifty color calculator of it's own that's soon to be even niftier.[/quote]
Yes yes, I found it and fell in love. Spread word to other people in another community I'm part of.

Totally random..don't want to hijack. But I run a free coloring book for horses: http://www.jf-studios.com/coloringbook…" onclick="window.open(this.href);return false; that you guys are more then welcome to use because it's for science! hahah!

TheRedHayflinger Fri, 06/25/2010 - 09:08

[quote="lillith"]Sounds good. I wish mine had been lol.

I am actualy ok at book learning I just have to re-write it in my own way to get it in, and doing diagrams/tables helps me condense the masses of words down to the essential message to learn it. Normally I can just read stuff and it goes straight in but this is a bit complicated. I have to jump otherwise it goes over my head. :bounce[/quote]

The hands-on was a good way to make class sizes smaller too..haha. Nothing like going into your equine repro class, 20 people was cap, 9 more wanted signed in by the teacher and he's like...sit through this first class and come back next week and I'll sign you all in....head down to the barn. He tells a few of us that had taken Mare/Foal Care to pull out all the mares on the front line and wrap tails. Hands us all a bunch of surgical sleeves, lube and says...we are going to find the cervix!

8 people showed up total the next week..haha. Ended up being a really fun class though, and since it was so small, we took a ton of "field trips" to farms and such and got to teach stallions to collect, handle a ton of horses, seen some neat surgeries (our teacher was a vet), and handle some really cute little reining/cow bred QH and Paints. Even got to see a stallion with no ears in that class (he was born out west and lost them to frostbite when he was a bitty baby)

Dogrose Sun, 06/27/2010 - 08:23

[quote="Third Peppermint"]
Speaking of KIT being filled with mutations... I noticed that humans get some spontaneous mutations that cause white markings (mainly face and belly?) and it seems to happen quite often. There's actually a facebook page for people with piebaldism and I think the main phenotype change is a white patch of hair right on the hairline of the forehead. I had no idea that was a KIT mutation, but apparently people can be born with it randomly, and then it can be inherited. My favorite are the loud white people, especially with a very dark complexion.
[/quote]

After I read this I did a bit of research just out of interest- there is some good stuff online, then I was on the bus a day or so later and what did I see but a young man walking down the street with a blaze on his forehead, way too white to be a bleached patch, it was was like a perfect triangle of pure white. Cool! I'll be going round studying people's hair now :geek: