User:Montanabw/Countercanter-Color genetics sandbox
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white horse genetics re mythology
[edit]Hi Montanabw, you mentioned on the talk page of white horse (mythology) that you could help with sourcing the genetics stuff. That would be great! Julia Rossi and I have discussed it a bit on our talk pages here and here as well as on the article talk page. I thought the sentence added to the lede covered the idea well enough, because it makes clear that this article includes technically grey horses as well as technically white horses. But as Julia suggests, maybe expanding into a paragraph explaining the distinction would be helpful. Whatever you can do – I appreciate the changes you made already. Best, WikiJedits (talk) 17:23, 21 November 2008 (UTC)
- Just pop in what you need on the article talk page and I'll see what I can do. Also feel free to read Gray (horse) and steal anything from there that you want. Montanabw(talk) 00:33, 22 November 2008 (UTC)
- Thank you. I'm not sure what is needed 'cos I don't really understand the explanations. Just perhaps something that makes clear that white horses in mythology aren't defined as strictly as genetics defines them? I think? Maybe the paragraph you wrote on the talk page could just go straight into the article :) WikiJedits (talk) 21:54, 23 November 2008 (UTC)
More about white...
[edit]The first mention of non-gray non-cream white horses in scientific literature was Sturtevant's A critical examination of recent studies on coat colour inheritance in horses Journal of Genetics 2, pgs 41-51. Here is what he wrote on the subject:
Mr W. P. Newell has supplied me with information about an interesting family of white horses. The ordinary white horse is of course merely an old faded-out gray, but this is a family of real whites. Mr Newell gave Professor W. E. Castle some information about these horses, on the basis of which Professor Castle considered the colour to be an extreme spotted condition dominant to the ordinary colours.[1] I have now some further information, which makes the case an interesting one. These horses are said to be somewhat variable in colour. To use my informant's words: "The colour of skin is white or so-called pink, usually with a few small dark specks in skin. Some have a great many dark spots in skin. These latter usually have a few dark stripes in hoofs; otherwise the hoofs are almost invariably white. Those that do not have dark specks in skin usually have glass or watch eyes, otherwise dark eyes....I have one colt coming one year old that is pure white, not a coloured speck on him, not a coloured hair on him, and with glass eyes." The term "glass eye" means a white eye. Therefore the colt described above is almost an albino in appearance. However, his sire is one of the dark-eyed somewhat spotted whites, his dam being a brown Trotter. Since "glass" eyes occur not infrequently in pigmented horses it seems probable that this white-eyed albino (?) is really an extreme case of spotting, plus an entirely independent "glass" eye. Mr Newell writes that white mated to white gives about 50% white to 50% pigmented. He reports only three matings of white to white. The results of these were, one white, one roan, and one gray.
I know you'll find this interesting. Also, is there any way you could get your hands on WL Pulos & FB Hutt's Lethal dominant white in horses Journal of Heredity 1969 March-April, 60(2): 59-63?? I so desperately want to see it. This is the "study" that started the whole "dominant white" deal. Countercanter (talk) 02:45, 6 January 2009 (UTC)
That reference above looks like it could be referring to "Sabino White" as well. Also called Maximum Sabino? I have lot of pics of white stuff like this I think. I hope it all gets explained soon as well. Sabino is said to cause a separate type of raon-ing by some aficionados. Fascinating stuff though. Arsdelicata (talk) 09:28, 6 January 2009 (UTC)
- Hi! I'm so glad you're curious too. What MBW and I have been discussing is where sabino ends and "dominant white" begins. So far it does not seem that there is any one gene that produces 100% white horses all the time. Furthermore, I'm desperately looking for that article because it is their "study" (which was based on a breeding program) that coined the term "dominant white" and labeled it lethal. And the more I learn, the more I'm starting to feel like a single allele, lethal in the homozygous state, which produces 100% white horses, doesn't exist.Countercanter (talk) 14:18, 6 January 2009 (UTC)
- Sorry to be poky to reply here. Arsdelicata, long story short is that some of what is popularly called "true white" or "dominant white" genes are clearly lethal when homozygous -- not in the precise way "lethal white" in frame overo is -- but rather that the foals die in the womb -- so it's different. On the other hand, as far as we know, the "sabino", "maximum sabino" or "sabino-white" is not at all lethal, ever. (No lethal whites in the Arabian, for example, though they can have Lavender foal syndrome, which is a coat color dilution lethal) CC has done some interesting research into Leopard complex genetics and tobiano and there is somehow a relationship there, too...but we don't seem to have any studies that tie it all together! Anyway, the point is that there is more than just sabino and gray and there are lethals connected somehow to some white coloring. There is also weird stuff like the increased incidence of melanomas in gray horses, also...all fascinating and still kind of a mystery -- at least to me! LOL! Montanabw(talk)
- Clear as MUD. The 1969 study that proclaimed the existence of dominant white was based on progeny ratios. There are other explanations for unusual progeny ratios, and that's why I'm looking for the article. "Dominant lethal white" has NOT been proven to exist.Countercanter (talk) 01:20, 7 January 2009 (UTC)
- Sorry to be poky to reply here. Arsdelicata, long story short is that some of what is popularly called "true white" or "dominant white" genes are clearly lethal when homozygous -- not in the precise way "lethal white" in frame overo is -- but rather that the foals die in the womb -- so it's different. On the other hand, as far as we know, the "sabino", "maximum sabino" or "sabino-white" is not at all lethal, ever. (No lethal whites in the Arabian, for example, though they can have Lavender foal syndrome, which is a coat color dilution lethal) CC has done some interesting research into Leopard complex genetics and tobiano and there is somehow a relationship there, too...but we don't seem to have any studies that tie it all together! Anyway, the point is that there is more than just sabino and gray and there are lethals connected somehow to some white coloring. There is also weird stuff like the increased incidence of melanomas in gray horses, also...all fascinating and still kind of a mystery -- at least to me! LOL! Montanabw(talk)
I just remembered that the American Singer Canaries are said to have two types of white, and the dominant form, they claim is Lethal.Dominant White Singer. ( they also have a non lethal recessive white. Sometimes people have an experience with one species and expect the same to be true for others. It is like that quest for the "theory of everything." The articles on Lavender foal syndrome, Leopard complex and the Overo and Tobiano sub headings I got into were quite good I have to back and read then carefully as they are really rich an full of information. Some aficionados I remember taking about "Linkage" that word is not mentioned in the LW or the Overo frame syndromes, but people said it meant that the gene that caused the lethal condition, and the gene that caused the color were very close to one another on the chromosome and therefore were usually inherited together. Fascinating reads, I keep having to go back and then the internal links also keep me going to other fascinating places.Arsdelicata (talk) 03:04, 7 January 2009 (UTC)
- It's not so much *confusion* because there are several kinds of lethal or pathological white spotting in mice. So I'm not saying that types of lethal white dominant spotting *couldn't* exist, I'm merely saying that we cannot just decide that a fifty year old study based on progeny ratios constitutes a really exceptional "proof." This is confounded by the fact that polygenetic conditions (when several genes that produce some white get together, the result is greater than the sum of the parts, in terms of the amount of unpigmented skin/coat expected). Anyway, very interesting about white spotting in canaries! More often than not, we can expect to find a condition across species. This is due to one of the most important eh, not rules, but themes of biology: genes are conserved.
- For example, suppose that ancestral horses, probably the ones that lived in the forests, were striped or spotted-striped live civets. When they gave rise to plains species closer to modern day horses, they may have lost their stripes. However, it's unlikely that they lost the *genes* necessary to produce stripes. Sometimes genes are re-purposed, but all in all, especially among mammals, we're all so much more similar than we are different! Especially with some of these genes that cause white spotting, which can be very high in the "gene hierarchy" and produce so-called "cascading" effects. KIT affects melanocytes early, EARLY in development!
- I was once under the impression that LWFS was merely *linked* with the frame overo phenotype. This is incorrect. The Ile118Lys mutation in the EDNRB gene is causative of the frame overo phenotype in heterozygotes, and lethal white foal syndrome in homozygotes. Countercanter (talk) 13:13, 7 January 2009 (UTC)
Thank you for explaining CC. If the study included pictures and a good amount of cases though, I sure would like to see it. I do think though, that some aletes get lost. Do you know if the genes for bay (agouti) ( and others ) have been re-purposed in the friesian Horse, or have they been bred out. What I am asking I guess is if in some horse breeds don't carry say the LP alete that makes the leopard spots ... was I maybe confusing alete with gene? ThanksArsdelicata (talk) 18:34, 7 January 2009 (UTC)
- See allele and gene. I get confused too! One thing we have to deal with is propaganda. APHA, for example, still "officially" says that "overo" is not necessarily correlated to LWS. Well, if you classify "splash" and "sabino" in the overo family, then yes, the statement is true. But "frame" is what CC is talking about. And when most people say "overo," they are really thinking "frame." So, well, horse politics once again rears its ugly head... oh and I also once heard a rumor that there is a lethal in the Peruvian Pasos, but that no one admits to it...may be just a rumor. As for "dominant lethal white," all I can say is that there appear to be cases where something other than LWS is going on. There is a type of "true" white that behaves like a dominant, in that only one parent is needed to produce it, but that it appars most such white horses are heterozygous and only pass it on 50% of the time...unlike the famous homozygous gray, which will ALWAYS produce gray offspring, there seem to be no whites that fit this pattern, hence why it is such a rare color and probably it is so rare because homozygotes are not produced...if there ever was, people's weirdness about color would suggest that it would be more widespread -- the way gray is.
- As for the Friesian thing, I don't know a lot about it. I know the mainstream registries will not register anything but black and are trying to weed out everything else, but genes are stubborn things -- occasionally a chestnut will crop up (which is logical, as a heterozygous black may not necessary produce chestnut offspring, but the allele will pass on, perhaps hidden for generations, particularly in mares, who produce fewer offspring than stallions). Then, naturally, someone thinks chestnut Friesians are cool and so has started a separate group just to breed them! As for bay, agouti is dominant over black, so if it's there, it shows -- breeding a black to a black will never produce a bay, though it might produce a chestnut if both blacks are heterozygous. On the other hand, I suppose a few bays might sneak into the Friesian gene pool, particularly if they have CC's "sooty" gene and look like bleached-out blacks. (Wishful thinking is an amazing thing) They can now be "caught" with DNA tests, but again, I think the Friesian registry gets rid of all the ones it finds...but I am sure that, again, someone thinks they are cool and breeds them anyway...humans are so very, very human... Montanabw(talk) 21:20, 7 January 2009 (UTC)
- Hope I'm not butting in... There is a red gene in Friesians, and certain lines known to carry it, but red Friesians can't be approved, and FHANA is now trying to eliminate the red gene by color testing stallions to be sure they are homozygous black. In that way, red Friesians will be eliminated (because you can't have a red foal with a homozygous black parent), and also the red gene will be slowly phased out of Friesians, at least FHANA registered Friesians. I'm not sure if FPZV has taken the same stance about requiring stallions to be homozygous black. Here is a neat link: [1] to a red Friesian stallion, he is FHANA registered, but not approved. Salito (talk) 15:02, 14 January 2009 (UTC)
- Interesting, but I had a hard time finding yer post as it was mixed in the middle. Thanks for the info and link though! Arsdelicata (talk) 17:05, 14 January 2009 (UTC)
Thank you very much for the allele and gene links! I am off to read them and understand. I see the linkage stuff was propaganda or wishful thinking <smile>. I'll upload the white looking horses I have under Cream_gene, we may also eventually want to look at the Marwari_(horse), and the Kathamawari Horse (spelling) because I have seen many videos on Youtube of these horses with pure white looking color and DARK eyes, yet pink skin! and NO SPOTS. I think a lead to White, maybe a dominant white not related to the Gray, can be found there. Arsdelicata (talk) 22:44, 7 January 2009 (UTC)
- CC will probably accuse me of oversimplifying, and I probably am doing so, but I'd say that many cases of white bodies-pink or parti-colored skin, but DARK eyes are probably sabino. There is an Arab described by scientists studying this stuff as a "dominant white," but his owners call him a "maximum sabino bay." IN short, I usually suspect Sabino for anything with dark eyes, and if the horse has blue eyes, then there is a much wider range of possibilities, though the sabino SB-1 gene (which apparently produces some, but not all "sabino" coloring) can produce white horses with blue eyes too. Montanabw(talk) 01:32, 8 January 2009 (UTC)
- I agree. Frame and splash produce blue eyes, not much else. You can certainly call those horses sabino-whites. Countercanter (talk) 02:24, 8 January 2009 (UTC)
- CC will probably accuse me of oversimplifying, and I probably am doing so, but I'd say that many cases of white bodies-pink or parti-colored skin, but DARK eyes are probably sabino. There is an Arab described by scientists studying this stuff as a "dominant white," but his owners call him a "maximum sabino bay." IN short, I usually suspect Sabino for anything with dark eyes, and if the horse has blue eyes, then there is a much wider range of possibilities, though the sabino SB-1 gene (which apparently produces some, but not all "sabino" coloring) can produce white horses with blue eyes too. Montanabw(talk) 01:32, 8 January 2009 (UTC)
Just another update. I did some digging and Professor Newell was the original owner of Old King, the original Nebraska White Horse. The descendants of Old King were the horses used in the original Pulos and Hutt "Dominant white lethal" study; the family that led them to believe that it was a homozygous lethal condition. That means that the description above is the absolute standard of "Dominant white." Countercanter (talk) 14:57, 10 January 2009 (UTC)
- CC, want the article rewrite from hell? (grin) See American creme and white horse registry. It needs a lot of help. It might be beyond help. I notice the "registry" site seems to no longer be maintained... repeal of the AQHA "white rule" seems to have taken a lot of wind out of the color breed registries. Montanabw(talk) 23:43, 10 January 2009 (UTC)
Brown
[edit]And now, more about brown. I sent an email to the researcher at Pet DNA Services of Arizona asking for information about seal brown. This is the lab that does the seal brown test, and I hoped to cite the correspondence. Unfortunately, it turns out there's patent work going on and he wasn't comfortable sharing anything other than that they do a test. Bummer! However he did say that the information was not published "yet" which makes me hope that it will be...eventually. Boo. Countercanter (talk) 14:29, 6 January 2009 (UTC)
- I'll stifle the irritation that they want the patent before releasing enough useful information to verify that they aren't just making it all up! (Very weird that this test does not have any affiliation with a major university-- most companies LIKE the universities to do all the grunt work of research for free, then the school licenses the test to a commercial lab like VetGen. UCD at least provides enough data that we can write an article that cites to a verifiable source. D'oh!!! Montanabw(talk) 17:39, 6 January 2009 (UTC)
Older stuff
[edit]Restarting...I think this comes off like I'm being short with you, but I'm short only on time; the tone is accidental.
They do not have "the" sabino gene, they have a sabino gene. What I'm saying is that the process of domestication seems to make the KIT gene mutation-prone. Each family of white Thoroughbreds, each family of white Arabians, the family of white Franches-Montagnes...each strain is a *different* mutation along the gene. And each of these genes can be expressed in a variety of ways. The Franches-Montagnes whites become MORE white as they age, and I'm sure you've seen the gamut of expressions of sabino in the Thoroughbred (etc.) strains. What I'm trying to say is that everything from a STAR or white coronet band to a maximally white horse is caused by mutations along the KIT gene. There are differences between all of these genotypes and their phenotypes, we simply lack the sophistication to tell them apart. Along the same lines, we often lack the sophistication to tell chimeric brindles from otherwise. Brindling in horses has many causes. It should be pointed out that many of the white-sabino families we know about were the result of "spontaneous" mutations.
As far as Arabians, who do you mean by "the breed"? When Shagya was born, who's word was it? Did not the breed undergo severe bottlenecking? I'll hold my opinion until I hear from you.
Genetics changes so quickly that by the time any book on equine genetics is published, I'd be suspicious. And, let me point out that just because someone records a pedigree does not make it true, even if the phenotype doesn't belie the inconsistency. Mares and stallions are mares and stallions, and it seems naive to think that any one Thoroughbred or any one Arabian is descended from all the horses it is reportedly descended from. I don't think any Thoroughbred is a "real" Thoroughbred. The probabilities simply don't support it. Therefore I don't think any frame Thoroughbred is less pure than any other Thoroughbred, just because he has the misfortune to wear it on his skin. If we had the technology, I might take any Thoroughbred, look into his genes, and say "Now, this gene that codes for ___ chemical pathway in the ___ cells of the intestinal wall is simply not found in REAL Thoroughbreds!" Color is a dreadful thing to be so singled out, especially since the metabolism is much more important to Thoroughbred type than color.
I understood also that Thoroughbreds and Arabians were registered "together" (vague term) until 1919?
Shagya-Thoroughbred crosses are considered Anglo-Arabians in many countries. I can't say "most" because I haven't counted but there you have it.
I will find some time this weekend to look through the assessments. Very interesting. More later. —Preceding unsigned comment added by Countercanter (talk • contribs) 17:36, 25 January 2008 (UTC)
- Working backwards. Well, the Shagya Arabian people, at least in the USA, consider them a separate breed, so I'm prone to go with it. As for TBs and Arabs, in the USA there was a separate Arabian registry started in 1908, but I don't know if the Jockey Club kept arabians on the books longer or not, I think the GSB had a separate section for Arabians well into the 1950's or 60s at least.
- The KIT gene will be a fascinating project to uncode. and Agreed, SB1 is "a" Sabino gene, not the only one, no argument there. However, there is, to date, no such thing as a true "white" (either "W" or SB1) Arabian, i.e. blue eyes and 100% pink skin. Period. Most "white" Arabians in the stud book were mis-registered grays, the rest are, quite literally, the less than a dozen horses worldwide who are a type of non-SB-1 "maximum Sabino" that show both dark and pink skin color under a white hair coat and they all (as far as I know) have dark eyes. Genetically, they test out as whatever color underlies the markings, i.e. Bay, Chestnut, etc. Now clearly, there ARE white Thoroughbreds, for whatever reason. I'll avoid the whole mutation question, but most breed registries have traditionally thrown out mutations. As for Overo, I guess I just have issues with people who falsify records and I'll bet a dollar to a donut that overo TBs are not the result of a spontaneous mutation, they are the result of someone's cropout Ah making a midnight raid (grin). Indeed, though breed "purity" is certainly an aspirational goal for many breeders, it is also true that bad records, human error, incompetence, and flat out dishonesty can always put some bloodline records into question (but for God's sake, don't say that to the Andalusian people! Horrors the flame wars!).
- As for "official" breed "purity," the breed registries do have the final say to be the arbiters of what's in and what's out. To go beyond that would be original research on our part, and the wikigods say that's a no-no. There is not a WAHO-affiliated Arabian horse registry in the world that accepts Shagya as a purebred as far as I know. He was originally imported to Babolna, I think, and I'm not sure, but I think it was the Hungarians themselves who figured out there were problems with his pedigree. Even if his color was due to the sudden spontaneous appearance was a spontaneous of mutation of a dilution gene (which I doubt), it would have been unacceptable to the breed and he would have been considered a cull anyway. Good thing he was allowed to be considered a foundation sire of a "new" breed. Shagyas in the USA are not considered Anglos at all, I'd have to check the breed registry guidelines, but I don't think they allow TB breeding.
- I'm just popping in quickly to say that "mutation" connotes something scary to many people. It means nothing other than a different code than before. It is not sinister, and NO registry throws out mutations. They'd throw out every single foal. Everything is a mutation, every living thing has had some "mistake" in the copying of its genes.
- The word "mutation" should NOT conjure the Teenage Mutant Ninja Turtles, any more than radioactive cancer therapy should trigger thoughts of Godzilla.Countercanter (talk) 22:00, 27 January 2008 (UTC)
- Yeah, I know about the "scary mutation" thing, lost a battle on a non-wiki project with some co-authors on that one, they wanted to say "mutation" because that was what the geneticists said, I wanted to tone it down to something like 'defective allele' but I lost. Maybe "deleterious mutation" is more accurate. (though that would be an understatement in the case of Godzilla ;-) Oh well. One of those things where language can be a minefield. Sort of like "Arab" and "Arabian." "Arab" is acceptable for spoken language, but is informal in written form, hence "Anglo-Arabian." Had a similar battle over someone who wanted to refer to stallions as "studs." I couldn't get through to them that "stud" is a spoken colloquialism, "stallion" is correct in formal writing, and that in writing "stud" refers either to a farm or a 2x4 in the wall! (grin) LOL! Montanabw(talk) 18:44, 28 January 2008 (UTC)
Color things...
[edit]"The eyes and skin of palominos and buckskins are often slightly lighter than their non-dilute equivalents." -- Locke, M. M.; Ruth, L. S.; Millon, L. V.; Penedo, M. C. T.; Murray, J. D.; Bowling, A. T.. The cream dilution gene, responsible for the palomino and buckskin coat colours, maps to horse chromosome 21. Animal Genetics, Dec2001, Vol. 32 Issue 6, p340-343.
Just to clear that up! Countercanter (talk) 19:05, 3 March 2008 (UTC)
Color stuff
[edit]I took out the phrase "no spotting patterns" in the genetics section because white markings (be it a snip, leopard complex blanket, or sabino-white) don't make a horse not black, and I think this is important to stress in an encyclopedic article.
As to the foal colors of smoky blacks:
[2] Approve Black Gold with "teal eyes" at birth. Buckskin and palomino foals often have blue eyes at birth.
[3] MEMC Ladyhawke "If you look closely you can see the bluish eyes that many cream dilute foals are born with."
[4] Concealed Gold shows the orangish ear tufts and blue eyes. "This foal, like many dilutes, has blue eyes at birth that will later darken."
On my "to do" list are to clean up the cream article and give more colors their own articles. I really want to make the palomino and buckskin articles about the colors, moving the "breed registry" info to its own section. I'd also like to modify the white markings article to make it more clear that there's not really much difference between a snip and tobiano...that it's all just white markings. So, that's my list.
Countercanter (talk) 15:36, 29 May 2008 (UTC)
OK, reply in more detail on your talk page. Montanabw(talk) 22:47, 29 May 2008 (UTC)
- "Approve Black Gold" is not champagne, but a smoky black sired by a perlino.
- From whom have you heard that single-dilute foals do not, contrary to popular belief, often have blue eyes and pink skin at birth and then darken? I have heard from breeders, as have the constructors of these websites, that single-dilute foals are often born with blue eyes that darken with age.
- "MEMC Ladyhawke" is not champagne, but a smoky black. Her sire is MEMC Tequila Quervo [5] (cremello) and her dam is Aswyn Nora Ashbrook [6] (smoky black). MEMC Ladyhawke has NO champagne phenotype OR genotype. Her breeder is a color breeder and if either of her horses had champagne in play, they'd know and be capitalizing on it. Tequila Quervo has *plenty* of offspring; if he were hiding champagne, he'd have produced one by now.
- Further to this point, read [12] case study. Kalamino is not champagne.
- Shall I go on? Countercanter (talk) 00:38, 30 May 2008 (UTC)
- This I understand. My only comment at this point is that Kalamino's chances of being champagne/pearl fall not under the heading "could very well be" but rather "would be incredibly unlikely." I'm sure we'll come to the bottom of this. Countercanter (talk) 15:20, 30 May 2008 (UTC)
Actually, I'm a little uncertain about the varnish in the newer photo only because I think he happens to combine true roan and varnish. The other photo, while not as pretty, is less ambiguous. Countercanter (talk) 00:04, 5 June 2008 (UTC)
- Oh, but that is a CLASSIC roaned out Appy. See them out here all the time. That other one, to me, was more ambiguous because the head was so light (LOL). Montanabw(talk) 08:17, 5 June 2008 (UTC)
- Right, it looks like a classic roan that is also varnish. The light head on the other one illustrated the difference between true, classic roan (dark head) and varnish roan (dark bony bits). Countercanter (talk) 15:19, 5 June 2008 (UTC)
Sounds good
[edit]Yum. Weaseling suits me fine.
The foundation bloodstock article looks nice and is quite thorough, though it reads a bit novelishly. In the second section, perhaps you ought to pare down the discussion of open/closed studbooks unless you plan to add in a link between the warmblood studbooks and foundation stock. What is the source? I resisted attacking the Thoroughbred section on "breed characteristics" with a steak knife...or my bare hands. I hope you're proud.
It is unethical, I think, to mislead people by citing sources that are known to be wrong. Just because somebody wrote it down and paid the publisher doesn't make it credible. And I direct both comments out generally, not at you. But I have major qualms with that and all other sorts of prejudicial comments that crawl out of the creepy, rotting remains of imperialism. Ew. To that end, I will state that of the many KIT mutations that produce white patterns that are present in the Thoroughbred population, roan ain't one of 'em. I have a university source that discusses KIT mutations (Haase et al. "Allelic Heterogeneity at the Equine KIT Locus in Dominant White (W) Horses" 2007) with Thoroughbred subjects.
As to "roan": What then is the protocol when it is a known falsehood quoted from literature that is mistaken, or at least takes cues from informal definitions? Do we take out the wikilink so that it doesn't mislead people into thinking that Thoroughbreds have the roan GENE, but keeps the word "roan" in the article? Should we modify the roan article to explain false roans like rabicanos, varnishes, greys etc? Explain the disparity between using the word "roan" on registration papers and True Roan, the genetic color? [13] Is this source sufficient? Countercanter (talk) 20:44, 31 May 2008 (UTC)
- Huh? I'm missing something here. News to me that there is an issue with roan in Thoroughbreds? Or is the roan article the problem? No, I wouldn't toss the wikilink, (fixing the wikilinked article a better solution) and if the Jockey Club says TBs come in roan, even if it's really sabino or something then what...tell the breed's own registry that they are wrong? If you have a good source for that, maybe show us. As for the color stuff, I sympathize, I DID do something like that on roan versus Sabino and [{Rabicano]] in the Arabian article, AHA also uses "roan" for rabicano and some sabino horses, Arabs probably don't come in true genetic roan, either, but the registry hasn't figured that out yet) but everyone helping work on it for FA feels all the color stuff is bloating the thing down...no win sometimes...
- I didn't note anything comparing the KIT locus to Roan coloring (In which article??) Care to explain? I'm all for getting things straight...but not sure what imperialism has to do with it? (smile?) Just fill in some blanks, seems a couple sentences got left out between your thinking and my talk page...?
- How about you go in and use hidden text on the foundation bloodlines article where you want to take a knife to it! (grin)? You know, my favorite <!--sticking annoying comments in different places--> thing? That way, I'll know where you are concerned and take a look at those parts again. As for the open and closed stud book thing, if you want to tweakthe warmblood stuff, go ahead, keep it a summary that directs to the wikilinks, and remember that open stud books exist elsewhere (the foundation article is intended to be really generic, covering Quarter Horses, etc...probably the dog people are even going to wind up weighing in at some point, I bet...)
- "Mislead people by citing sources that are known to be wrong" Huh??? Not sure what you mean there...I would feel free to challenge the accuracy of a source, but I would hesitate to attribute motive-- I for one do not put in sources I "know are wrong," I certainly think they are correct at the time I put them in-- though if they are wrong, that's what the rest of us are for -- to point out other info or viewpoints. Anyway, just clarify your concerns and we shall see what can be done! Montanabw(talk) 03:23, 1 June 2008 (UTC)
Amber-eyed zebra
[edit][14] Just thought you'd find this interesting :) Countercanter (talk) 01:19, 14 April 2009 (UTC)
- Very cool! If amber is related to green, I do wonder if in horses, there is a champagne gene connection, somehow... Montanabw(talk) 22:42, 14 April 2009 (UTC)
- I'll wager not, at least not that way. The gene on which there is a mutation responsible for the champagne phenotype is one of many, many factors responsible for eye pigment. Read the rest of that lady's article, if you get a chance.. Countercanter (talk) 01:04, 15 April 2009 (UTC)
- That looks just like the yellow eyes on the PR horses. Arsdelicata (talk) 21:31, 3 August 2009 (UTC)
Grullo versus anything else
[edit]Howd'ja reckon, how should the Grullo category in Commons be renamed? For consistency it should at least be "Grullo horses", but I'm under the impression that "grullo" in fact is a term that's in limited use (limited to um, mustangs and South American breeds or something?), and grey dun would be more widely-known. Pitke (talk) 12:35, 10 November 2009 (UTC)
NOT "gray dun" -- that is a term never used in the US. (A dun with gray genetics will turn white with age) "Grullo" (or also "Grulla") is a term that is actually Spanish and has become popular for use with the horse breeds in the western USA, particularly quarter horses. Genetically, it is the dun dilution on a black base coat. In the USA, we often say "blue dun," or "mouse dun." I suppose the genetically most correct tern is "black dun" (akin to bay dun and "red" (chestnut) dun"), and even some geneticists (specifically Sponenberg, I think) are starting to say that. I guess if I were to use the most common term recognized by horse people, I'd say use "blue dun," but if you think that will cause heartburn with other wiki translations, "black dun" is not really a traditional term, but it is at least genetically accurate. Hope this helps. Montanabw(talk) 04:10, 11 November 2009 (UTC)
- "Blue dun" would be really confusing but "black dun", while genetically correct, would be too (since the horses are not black either); I'd go with "mouse dun", it's a term understandable by those not in the knowing, and actually related to many toher languages' terms for the same colour. Pitke (talk) 10:35, 11 November 2009 (UTC)
- "Mouse dun" should be a good compromise given that we have to deal with multiple languages. Maybe on the relevant page, make a note that in English, they are also called Blue dun and Grullo or Grulla. That should probably placate those who have great fondness for the other terms. Montanabw(talk) 03:34, 12 November 2009 (UTC)
I think that 'mouse dun' is now being used predominantly for dun dilution on a brown / seal basecoat, bay dun for dun dilution on red-bay base, and blue dun very widely for dun dilution on black base. (PippaRivers (talk) 16:22, 4 February 2011 (UTC))
Added: see http://www.brookridgemorgans.com/Lovey.htm (click the thumbnails) for some pics of a gorgeous 'mouse' rather than 'blue' dun. (PippaRivers (talk) 16:51, 4 February 2011 (UTC))
It's about time to let Palominos roam free
[edit]How about properly dividing the Palomino article into an article about the colour and an article about the colour breed? I've done this in the fi version (fi:Voikko and fi:Palomino) and I'm positive it'd work here as well. This way these two could be kept separate, and they would probably be less confusing no? I'm just editing Palomino (sorry :X) and I've found golden stuff such as, in the main section, a random claim that "white markings up to this and this sizes are acceptable", never mentioning this discusses (one of) the colour breeds(s) standard, not the genetic colour... Pitke (talk) 09:08, 2 December 2009 (UTC)
- You make a good point that the "registry" standards are mixed up with the color itself and the article should probably split that stuff into its own section. I also would think it isn't a bad idea to do an article on the palomino "registries" such as the Palomino Horse Breeders of America (PHBA) (the biggest group) and their rivals, [the http://www.palominohorseassoc.com/Palomino horse association]. Similarly, we have an article on the American Paint Horse, which IS sort of a "Breed" (in that there are standards beyond just color), more or less, but we also have APHA about the organization. But I oppose a split for a palomino "breed". "Palomino" is a color, not a breed Palomino is an incomplete dominant, there is no such thing as a "true-breeding" palomino and hence Palominos cannot ever be a "breed." It's a color that horses of many breeds happen to carry. Just like "Bay" is a color, not a breed, even though Agouti is actually dominant and in a breed such as the Cleveland Bay IS in fact one breed trait (among others). And in the USA, believe it or not, we once even had a "bay horse registry." Yes, send in a photo and a few dollars and they'll send you a nice certificate for your grade bay horse! (Don't get me started n that one...) In short, I have no problem in splitting off the stuff that is a "registry" standard into its own section and maybe into its own article, but not splitting the article between the color and a nonexistent "breed." Does that make sense? Montanabw(talk) 03:22, 3 December 2009 (UTC)
- There is a reason I used the term "color breed" you know. Relax, I believe you've explained in detail this colouyr registry thing to me one or twice already. I was just thinking that to combine all the palomino registries into a collective article could be more useful than to have a single article for each registry ever. Presuming, of course, that there is not so horribly much to tell about them. —Pitke (talk) 10:51, 3 December 2009 (UTC)
- OK, I shall chill. Some, anyway (LOL!) I like AAABACHA! Let's start a movement! I am of the opinion that at this point in time, there isn't a pressing need for an article on the Palomino registries unless those who care push for one, and PHBA is really the only one worth bothering about (the others seem to be started by people who think PHBA is too stringent and fussy). And actually, I think I moved to (successfully) delete the "Spotted Saddle Horse" registry -- TWICE!. Oh. But we DO have an AAABACHA (looking at User Josette and ducking...!) It's called the "American Warmblood!" LOL! (running, ducking, grinning...). Montanabw(talk) 23:18, 3 December 2009 (UTC)
- I started to do this with Pinto horse and Pinto Horse Association of America. I truly hate when articles which should be about a color include arbitrary rules that have nothing to do with the color. Anywho. Please do snip out those bits in the Palomino article and fence them in their own section or article. They raise my blood pressure. Not to be dramatic or anything... Countercanter (talk) 14:25, 4 December 2009 (UTC)
- I think we did. Their own section, at least. More could be done. I don't know what to do when the reality is that a "color breed" registry with a multi-million dollar budget (probably) is promoting a concept that is genetically impossible (the "true-breeding' palomino). Sigh. Montanabw(talk) 22:38, 4 December 2009 (UTC)
Wishfulness or facts - a Brown story (with over 80% more numbers!)
[edit]IMHO, I find the distinctions between dark bay, "sooty" bay, and "seal brown" to be kind of annoying. Apparently there is a "seal brown" test, and I agree that there is sootiness clearly visible in other colors, but I still do not fully really get this or have a handle on how much of this is genetically proven and how much is wishful thinking... (partly reflecting my annoyance of those who like to market dark bays as "black bays"--as if they are more likely to produce black than others, which they are not... ). OK to move this to my wiki talk page to chat more or just move it to the discussion page here... Montanabw (talk) 00:13, 26 July 2010 (UTC)
- I have to comment what you said about marketing brown horses by saying they are more likely to produce black. Under certain circumstances, they are. 1) premise: parent A is capable of producing black non-affected (that is to say, not HZ for grey, silver, cream etc, and carries Aa) 2) premise: the brown parent (parent B) is a true brown (as opposed to genetically non-brown mimics), but its (or parent C's) precise genotype in the agouti allele is not known. 3) premise: brown is a colouration genetically separate from black and bay; four alleles of the Agouti gene exist, responsible for wildtype bay (A+), bay (AA), brown (At), and black (Aa) phenotypes, A+ being primary dominant, AA secondary dominant, At tertiary dominant and Aa recessive (which I believe is the way science sees it these days). If premise 1 fails, no combination can produce black offspring. If premise 3 fails, the basis of the calculus is faulty. Premise 2 is there for "realism" (to simulate a situation where a stallion is not tested for colour). Illustration time. HZ stands for homozygous. Pitke (talk) 15:36, 26 July 2010 (UTC)
- For simplicity's sake, there will be only 2x3 series, and parents will mostly be HZ for EE. No parent will be a carrier of dun, cream, silver, grey or other additional factors.
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- Thus I dare claim that a brown horse may be more likely to breed black than a non-At brown bay, wildtype or not. Pitke (talk) 15:36, 26 July 2010 (UTC)
- Here's why I beg to differ. First off, BOTH parents each carry two alleles for each gene and will each contribute ONE to their offspring, so I dread to say this, but I think your chart is oversimplified! ( =:-O ) This is complicated by your use of totally different coding for genetic alleles than what I use, but we'll figure that out. In my examples, black is created by the E allele (E) and bay by the Agoti allele (A). For purpose of discussion, capitals mean (E and A) dominant alleles, lower case (e and a) meaning recessive alleles-- (which is the way I've learned to discuss genetics and how it is used in the materials at UC Davis, where I get most of my info) Thus a black horse is EEaa or Eeaa, (and this is regardless of other modifiers for sooty or fading or whatever on either the extension (E) allele or the agouti (A) allele.) (Also agreed: we aren't going into the dilution alleles here, because they are completely different modifiers added on top of these base genes). Bays of all variations are EEAA, EeAa, EeAA or EEAa; in other words, they have at least one allele of dominant Extension and one of dominant Agouti, whether homozygous or heterozygous. Thus, it seems to me that most of the coding for "wildtype" or "brown" or "sooty" or whatever variation on bay is irrelevant as to whether a horse can throw black. A black horse does not have the dominant Agouti allele that suppresses the red (e) allele to the points. Beginning and end of story. Thus, a bay/brown/whatever-with black mane and brownish-or reddish coat always MUST carry at least one copy of E (EE or Ee) in order for black points in the first place, and thus could throw a black if it is also Aa, depending on the genetics of the other parent. (A bay that is AA will never throw a black, because Agouti is dominant over the Extension allele) Further, all these wildtype and whatever other variants, with the exception of "seal brown" (and I am not 100% sure of how good that lab is that has that test) are NOT proven yet by DNA tests locating the actual genes, as far as I know (If I'm wrong, please provide sources; I do primarily go with what's at UC Davis, maybe the European labs do have such tests). All the other proposed (but not proven) modifiers of the Extension or Agouti bay coat alleles don't change the fact that there's ALWAYS a black (E) gene in there. So therefore, any bay-type horse, regardless of all the little superscript letters that might be added to its base A allele -- is no more likely than any other kind of bay[type horse to throw black, as it's all in how the primary genes line up: AA=never, Aa=maybe. EE or Ee= possibility of black, depending on other genes, ee = black never possible.
Let's take examples of just bays. Remember that chestnuts can carry agouti (A) because it's masked on a red horse:
- AAEE x AAEE= 100% bay, no possibility of black or chestnut
- AaEE x AAEE= 100% bay no possibility of black or chestnut
- AaEe x AAEe = Offspring possible: AAEE, AaEe, AAEe, AaEE (all bays) Aaee =chestnut or AAee=chestnut but black not possible (no aa combo possible). I think that works out 75% bay, 25% chestnut.
- AaEe x AaEe = 50% bay (AAEE, AaEE or AaEe), not sure how the percentages crunch, but chestnut possible with (AAee, Aaee aaee), black possible with (aaEe, aaEE) Traditionally this combo is over simplified as 50% bay, 25% chestnut and 25% black, but I don't see the combos actually working out that way statistically. but 50% of throwing A and 50% chance of throwing the E allele, so more bays than anything else
Now let's take chestnuts (eeaa or eeAa or eeAA) and blacks (EEaa or Eeaa): Chestnut without Agouti x black eeaa x heterozygous black (Eeaa) = 50% black, 50 % chestnut eeaa x homozygous EEaa = 100% black These two above combinations of parents will never produce a bay
Chestnut with masked agouti x black: eeAa x Eeaa= Black, chestnut or bay possible here (I won't bank on my math, but I think 25% probability of bay, must get both E and A, 25% probability of black, must get E and not A, 50% chestnut, as it doesn't matter if A is passed on or not) eeAax EEaa= 50% black, 50% bay, no possibility of chestnut --(E) is always passed on eeAA x Eeaa = 50% bay, 50% chestnut, no possibility of black --(A) is always passed on eeAA x EEaa= 100% bay
I'm sure I missed something here, but I hope this made sense. For example, this dark bay horse has thrown black offspring, but so has this blood bay horse. So, now can both of our heads explode? :-D Montanabw(talk) 01:46, 27 July 2010 (UTC)
- I just explained way up there the (currently prevalent?) theory about multiple degree dominant alleles of the Agouti gene, which would have, in this case, not two (black and bay), but four alleles. Thus just A and a aren't enough to mark them. AA is the longer way to say A, meaning "the A allele of the A locus" (locus being the normal letter and the allele the sup one). Just a quick remark before I dash off to work, will come back for more discussion. Pitke (talk) 02:49, 27 July 2010 (UTC)
- I actually think the answer to your question is, no, not current, some of the stuff you have is now outdated since the (recent) mapping of the horse genome, just not sure how much. One thing sure: Agouti doesn't "make" black color, it just suppresses it to the points. (The last four years of equine genetics has been a roller coaster ride!) UC Davis intro here,better page about the tests here, is my main source of info, and their site explains E and A as I understand them. (Their main page stuff on Overo is wrong and in need of updating, and they weasel a bit even on admitting their own lethal white test IS a frame overo test -- see the lethal white syndrome article if you care for details. I think they are politically sucking up to the APHA, but I digress) Maybe peek at Equine coat color genetics and see what you think of what's there too. Also read that Agouti article linked above. Now, I'm going to oversimplify so I can understand myself: Essentially, I think what you call Aa "recessive" is what I am calling "a" or, in other words, whatever happens when the agouti allele is recessive or switched "off" (as in a black horse) No suppression of black color to the points. However, to get a black horse, you also MUST have the dominant "E" switched "on"; otherwise you have a chestnut (e). Now, you tell me if what you call "true brown" At, is the same as what we have in the seal brown (horse) article, for which there appears to be a DNA test. ( And here's the seal brown (they call it At) test.) Also note that the whole thing about some extension genes being able to override Agouti has apparently been disproven as explained here I do "get" what you call a "wild" bay (i.e. not a lot of black on the legs), but I don't think there is a DNA test for it yet. And to be clear what shade do you call a "bay" AA? For example, would that fit this horse, which, shade wise, I classify as a classic bay or a "blood bay." OK, getting rummy now, my eyes crossed and my brain just went on strike! Back to you! Montanabw(talk) 03:20, 27 July 2010 (UTC)
- Random note. What makes you think I don't know that E (instead of A) activates the ability to create black pigment? Pitke (talk) 11:58, 27 July 2010 (UTC) ← Rhetorical question, me hoping we could stay on the same level of genetics without dropping back to the basics of the basics whenever our views differ. Comments later when I have the energy to look into it.Pitke (talk) 12:01, 27 July 2010 (UTC)
- Not an insult, more a question and wondering why it was left out of the mix, as it plays a role here. I for one find genetics pretty daunting, and we don't use the same lingo. (It seemed that when you said "black (Aa)" you were arguing that recessive a = black, which is doesn't, Agouti has nothing to do with black as I understand it, Agouti merely suppresses black when present) Also wondered if you are arguing that E can somehow trump dominant A and throw a black with some dominant A allele, which, at least, the way I understood the black DNA test, is impossible. If A is present -- in any form (other than recessive a) --then you have bay (in some form), not black. I guess my point is that I cannot see how any Aa bay is more likely to throw black than any other kind of Aa bay, (At, or whatever) and no AA bay could ever throw black. No one seems to have sootiness, or flaxen, or liver chestnut figured out yet, and even the seal brown test has to first test for Agouti...
- Ok, I think I see the problem here. Well, at least one of them. I'll try to keep this simple and clear.
- "Locus" means a precise place of the genome. Every locus is responsible for something (e.g., the "Extension" locus is responsible for whether a horse can have black pigment or not, the "Agouti" locus being responsible for whether the black pigment (if it's present) is restricted, and to what degree). We agree on this.
- "Allele" means a version of a gene, located at a certain locus. For example, the Extension locus has alleles E (allows for black pigment production) and e (no black pigment produced). We agree on this.
- Where we part ways: I use the more exact way of marking genotypes, that tells both the locus (such as A for "Agouti") and the alleles (such as A for "Agouti - bay"). Where Montanabw would use "AA" to denote a horse homozygous for the A allele of the A locus, I would use "AAAA". I find this way more useful when it comes to loci with more than two alleles (such as Agouti, which has + (universal allele mark for the wildtype allele), A, t and a). When discussing loci with two known/proposed alleles (such as Dun, which has + (dun), and n (not dun)), I don't find the mark-up necessary or even useful.
- Alleles come in pairs, and dominance determines which allele "wins": for example, E is dominant over e, so both EE and Ee genotype horses are genetically capable of producing black pigment, whereas a ee genotype horse is not.
- Where we part ways: I think of the Agouti locus as having four alleles. In addition to the A and a ones that "everyone" knows:
- Sponenberg proposes (1996) a wildtype Agouti allele (+), responsible for a bay-like (but stronger) restriction of black, dominant over the A (bay) and a (non-restricted black) alleles. This seems widely accepted/unopposed, if we're not counting the (vast) majority (?) of people who don't make a distinction between a bay and a wildtype bay.
- The "brown Agouti allele (t)" (the t allele being responsible for the only slightly restricted black phenotype, and being dominant over the a allele but recessive for the + and A alleles (or the A allele if one wants to ignore +)) theory was widely supported, but isn't any more after brown horses, when bred to each other, were found to sometimes produce bay offspring (according to the theory, this should be impossible). Furugren points out (2000) that the distinction between a dark bay (Pitke: maybe really really sooty too?) and a brown is all but clear. This article mentions the At theory, but does not cite its source.
- Ok, I think I see the problem here. Well, at least one of them. I'll try to keep this simple and clear.
- For my own ease, I call the Agouti allele a "black" instead of "unrestricted black if E present" or anything such, just because if I called it that, I would feel the need to add such redundant disclaimers everywhere, and call, for example, the Agouti allele A "black (if E but no Z or Cr present) restricted to points"... I will also call, if needed, the Extension allele E "black" (as opposed to "black pigment producable") and the e allele "non-black". And please, no rants over how "non-black" is not a horse colour recognised anywhere in the States :P Pitke (talk) 19:01, 27 July 2010 (UTC)
- The E locus actually is included in the calculations, I wonder how you could have missed it.
- With "bay" (or AA_), when I talk genetics, I mean horses like, but not strictly restricted to this. Pitke (talk) 19:01, 27 July 2010 (UTC) And ignore additional info (sooty, blood, light, etc) about the shade. Which of course means that I think of the wildtype bay as a different colour than the bay, not as one of its shades. Pitke (talk) 19:09, 27 July 2010 (UTC)
Here, a 4-allele chart for your convenience
[edit]Here's something for you, copied from the Finnish Equine colours article. It shows how the 4-way agouti locus proposedly behaves. The table OF COURSE supposes the horse has the E allele and can produce black pigment. Pitke (talk) 19:09, 27 July 2010 (UTC)
Locus A | ||||
X | A+ | AA | At | Aa |
A+ | A+A+ wildtype bay |
A+AA wildtype bay |
A+At wildtype bay |
A+Aa wildtype bay |
AA | A+AA wildtype bay |
AAAA bay |
AAAt bay |
AAAa bay |
At | A+At wildtype bay |
AAAt bay |
AtAt brown |
AtAa brown |
Aa | A+Aa wildtype bay |
AAAa bay |
AtAa brown |
Aaaa black |
|}
- What we both probably need is Sponenberg 2009 (he just updated it!) 2003 is in google books, but it's pre-horse genome map. What you call brown I assume is what I am calling "seal brown." (?) We DO agree on what a "normal" or "classic" or "blood bay" is. Yes. I think where you lost me was describing Agouti and "black" in the same sentence: Agouti CAN be present in a chestnut, it's just that no one cares because there's no black to suppress. Agouti and black have nothing to do with each other unless they collide in the same horse. (and hence, I wonder if anyone has studied if At produces liver chestnuts, too? Would be logical) I am now about to be really annoying and say, "but if Agouti creates bay, then, other than the recessive allele (which I call a, you call Aa, but same thing), if there's an expressed form of dominant Agouti (A) involved, they are STILL ALL BAYS (of one kind or another!) LOL! Personally, I don't really see how "wildtype" and "seal brown" are all that big of a deal. (Dun is the original "wildtype" color, after all.) They are simply interesting variants on bay. Seal brown also doesn't seem to encompass all horses identified as "dark bay" (which may include the sooty thing). My point is that even if you grant wildtype and seal brown as somewhat distinct modifiers from classic bay, my position is that none of them are any more likely to throw black than any other. Agouti always will suppress black if the dominant allele is passed on to an offspring. A side note: There IS a dun zygosity test at UC Davis now --they haven't isolated the specific locus, but they have enough nearby markers that they are selling it. Interesting. Montanabw(talk) 20:54, 27 July 2010 (UTC)
- Personally, I don't really see how "wildtype" and "seal brown" are all that big of a deal. (...) They are simply interesting variants on bay. Seal brown also doesn't seem to encompass all horses identified as "dark bay" (which may include the sooty thing). My point is that even if you grant wildtype and seal brown as somewhat distinct modifiers from classic bay, my position is that none of them are any more likely to throw black than any other. Agouti always will suppress black if the dominant allele is passed on to an offspring. >> Supposing the four-allele theory is true, they *are* a big deal because they would be genetically as close to each other as bay and black are. A+ and At would not just be "another" AA (or bay allele if you will). The multiple dominance thingo is kind of complicated, I know, (the table illustrates it pretty neatly and clearly IMHO), but it's crucial; (the proposed) A+ and At musn't be thought of as "just versions of AA ("the bay gene") because of their different behaviour.
- If, as the theory suggests, At exists, it's recessive for AA but dominant over Aa, and thus cannot mask AA but can mask Aa - meaning that a At phenotype horse (a seal brown horse) can be either have AtAt or AtAa in its Agouti locus, and nothing else, and thus has a theoretical 50 % chance of carrying the "unrestricted black" factor.
- AA would then be able to mask At and Aa, giving a AA phenotype horse (a bay) a theoretical 33 % chance to carry the Aa factor.
- The A+ would on the other hand dominate over all the other alleles, meaning it could mask any of the other three alleles, which would give a A+ phenotype horse (a wildtype bay) the theoretical chance of 25 % to carry the Aa factor.
- In nutshell: A+ dominant over all others → a wildtype bay can be A+A+, A+AA, A+At or A+Aa. 25 % of the cases an Aa exists.
- AA is recessive to A+ but dominates the rest → a "regular" bay can be AAAA, AAt+ or AAAa. 33 % of the cases an Aa exists.
- At is recessive to A+ and AA but dominates over Aa → a seal brown horse can be AtAt or AtAa. 50 % of the cases an Aa exists.
- Aa is recessive with all the others → a black horse can only be AaAa. 100% of the cases there is a Aa.
- Thus a seal brown horse would be, in theory, 51 % more likely to carry (and pass on) Aa than a bay horse, and 100% more likely (read: "twice as likely") than a wildtype bay horse. Pitke (talk) 19:00, 28 July 2010 (UTC)
- Just found this: http://www.ca.uky.edu/gluck/AGTRL/Guide%20to%20Color%20Gene%20Testing.pdf and http://www.ca.uky.edu/gluck/AGTRL.asp#color Another useful source, (though some of their explanations are a little awkwardly-phrased) and UKy is another reputable University for things equine. More later. Montanabw(talk) 19:11, 28 July 2010 (UTC)
- OK, to answer the above, that's where we part company. Yes, a black horse has to be aa. No argument. But the rest of your math just makes no sense to me in light of random genetic selection (I'm saying that nice, I'm not trying to be mean). Aa or AA will produce bay. ALL the dominant alleles, A+, A, At are going to dominate over the recessive (a or Aa). So, given that a horse gets one allele from each parent, it's irrelevant which A (dominant) allele it is, it will always trump (a) when present. Thus if you only look at a horse that is Aa, whether that A is just plain A, A+ or At, if it is bred, there is a 50-50 chance it will pass on the dominant (A, any form) allele or the recessive (a) allele, depending on which allele landed in the egg and sperm. If the other horse was black (aa), it's a 50-50 chance of black or bay, period. Let's compare these to the most dominant gene of all, gray, which trumps everything. A homozygous gray will always throw gray. A heterozygous gray will have a 50-50 chance of throwing gray when bred to any non-gray. There's no such thing as an allele that is going to shove another allele out of the way in a sperm or egg because it's so dominant that it can bully the other alleles! Or am I missing something here?
- Next, do you have ANY proof that A+ is dominant over any other type of Bay? Absent a study, I actually beg to differ, based on observational evidence that one just doesn't see as many wild bays as classic bays (at least in Arabs, Morgans, Thoroughbreds and QH's, which are the breeds I'm most familiar with) -- also a lot of "funny" bay horses may be influenced by pangare or even possibly rabicano. As for At and A (AA) dominance, also, is there a study on this? Color wise, bays happen to be my favorites, actually, so I'm sort of into figuring this out! Montanabw(talk) 19:47, 28 July 2010 (UTC)
Here's a puzzle for you, taking animals I know personally: This "blood bay" horse and this "brown" or "dark bay" horse have the same bay sire, a horse that was not dark bay or seal brown, but was a darker and richer red shade than the lighter mare, though redder than the "brown" mare. He had a grandsire about the color of my dark bay mare. The blood bay mare had a blood bay dam exactly the same color, (by a sire exactly the same color, he was by this horse.) The dark bay mare had a heterozygous gray dam, who was out of a classic blood bay mare (I remember the mare) and on her sire's side, the closest bay was this horse, also a classic bay: (click for photo). Now, I admit I have never tested the dark bay mare for seal brown, so it's also possible that she's sooty, not seal brown, but either way, she's darker than all of her ancestors for whom I have memory or color photos. (she has lighter flanks, some lighter hairs on her face. this is her and her almost-identically colored buddy Interestingly, she has 5 full brothers and sisters. Counting her, they came out 3 dark bays, one blood bay, two grays. Montanabw(talk) 19:47, 28 July 2010 (UTC)
- Soo... what's the puzzle? The dark bay/brown horse linked at the beginning looks like a sooty bay to me. After seeing a sooty bay mimicking brown this convincingly, I have recalibrated my internal "bay vs brown" scanner... Pitke (talk) 08:24, 29 July 2010 (UTC)
Gotta bung my oar in here .... I was one of those chasing for tests for various different forms of agouti, and I don't suppose for one moment that we have them all yet! I have another couple of things to throw into the pile - what about seal-browns which, when crossed with red-bays (no sooty) produce bay-browns? (Brown, not nearly-black, body coats, with redder fading at the normal 'seal' tan points? And here's a (possible) way to pick out the sooties from the others: diet. Intensive feeding of high-betalain-pigmented stuff (such as sugar beet) seems to (quite radically) intensify the sootiness of a sooty's coat, while serious restriction of intake of those pigments 'cleans up' the coat. Smutty-palomino owners have been playing the 'clean up the coat for the ring' game with this one for quite a while now. Diet experiments on my own chestnut-sooty animals have given me some striking differences in year-on-year coat colour when all else in their regime has stayed the same. Just a thought .... though you'd have to own or have sole management of the 'is-it-sooty' animal for at least three years to see what it did :o) (PippaRivers (talk) 16:33, 4 February 2011 (UTC))
- That's the problem; Sponenberg 1996 is a bit outdated, particularly since the horse genome was mapped in 2006. What I am trying to determine is what's been figured out since then. 1996 stuff is mostly theory, unless someone has mapped the gene and studied it since. I guess, at root, I question how many of these supposed coat modifiers work the way they are hypothesized: Clearly, some things have turned out to work just as proposed. But other things have not. Just as an example, UC Davis turned out to be quite a bit off about "overo," even though they still keep the incorrect info on their web site. (Sabino, Splash and Frame all different genes, and Sabino still not all figured out, only SB-1, there clearly are others) Almost everyone was wrong about there being such a thing as "lethal" homozygous Roan. "Flaxen" is another example: It seems to breed true in the Haflinger, yet, no one has really studied it: in other breeds is doesn't appear to be dominant, or even all that transmissible, two flaxen horses can produce a very ordinary chestnut. So as far as all these examples, what I wonder about is how we understand the dilution modifiers reasonably well now, but they haven't studied the "darkening" modifiers nearly enough. Another, unrelated question: What do you think of the horses here that the seller describes as "bay rabicano"? We see a lot of this light bay, silver-tail, usually no roaning stuff in certain lines. "Bay rabicano" horses more often than not have no roaning, just the silvering in the mane and tail, thus they are often quite different from chestnut rabicanos, who almost always have the distinct roaning but normal manes and just a bit of a white "skunk tail. Wonder if they are even the same thing. Thoughts?? Montanabw(talk) 20:00, 29 July 2010 (UTC)
- So what did cause the distortion of roan inheritance? I'm dying of curiosity here! As for the "bay rabicanos", I see many have slight silvering near their groin/flank, that would be roaning there, while some seem to only have the tail ring. "Sahere" also seems to be rabicano, with some lovely "guard white" at the mane. You would wonder if the rabicano doesn't also have a range of expression (like spotting patterns do) instead of producing consistent patterns (like roan does). On other stuff, I read somewhere that sabino is more flashy on chestnuts, and more subdued on blacks... Clearly there will be enough excitement in the equine colour world for us even when we populate rocking chairs for our edit wars >w< Pitke (talk) 20:21, 29 July 2010 (UTC)
- No clue about the roan thing, but here is a little of what I do know: UC Davis. Countercanter put in a bit more stuff in the Roan (horse) article. Apparently UCD had a pretty extensive study even pre-DNA test where they concluded that there had to be such things as homozygous roans and that it wasn't lethal. My guess, and it's just a guess, is that even though roan is dominant, at the same time, it's kind of a weird color that is less popular than big flashy spots or cool-looking dilutions, there just wasn't any real push to breed for it. (Scratching my head trying to think if there's a breed that is predominantly roan and cannot think of one). And yes, there is some sort of thing where sabino (and white markings in general) does seem more vivid and flashy on chestnuts...the bays seem to mostly confine themselves to high white and bald faces, the Budweiser Clydesdales thing... User:Countercanter was trying to explain to me how there is some correlation with chestnut and more white, but apparently what it is is not yet determined. I wonder if it's because chestnut is the most recessive color of them all? The one thing all this stuff seems to have in common is that these genes all seem to hang out in the general vicinity of the KIT locus. I am not clear enough on genetics to understand how all this works, but KIT has a lot to do with many of both the white patterns and roan and even some white markings that don't fall into a spotting pattern. Oh, and speaking of sabino and rabicano, if you want weird, the same dark bay mare I noted above? She's now 30 and getting VERY distinct roaning on her upper neck and forelegs. Most folks say she's just getting old and going gray, but the vet thinks she has a touch of sabino; her sire had a body spot that came and went from year to year, plus he had a huge white snip that I cannot recall if it extended onto his lower lip, but may have. You can see the roaning a little in this photo, which was taken when she was 27. It's more obvious now. Now, of further weirdness, there is ancedotal stuff that blood bays don't get this graying/roaning thing as they age, while dark bays (whatever makes them dark bays) do. What I can tell you is, having owned four bays that made it into old age, it IS true that the blood bays didn't get really any graying to speak of, while the dark bays did. Wonder what's up with that? Montanabw(talk) 17:35, 30 July 2010 (UTC)
- Ardennais (horse) and Belgian (horse) are two breeds that have a lot of roans. Pitke (talk) 18:09, 30 July 2010 (UTC)
- Make that Ardennes (horse) (but probably wide to create redirect) US Belgians are almost all chestnuts, actually, you see some with roaning or pangare, but plain old chstnut is almost a breed trait here. The Brabant variant in Europe may not be, that I don't know, I do note commons has a lot of roan and bay Brabants... not sure the statistics on prevalence. Quarter Horses have many roans, but many more of other colors... Montanabw(talk) 18:14, 30 July 2010 (UTC)
- Ardennais (horse) and Belgian (horse) are two breeds that have a lot of roans. Pitke (talk) 18:09, 30 July 2010 (UTC)
- No clue about the roan thing, but here is a little of what I do know: UC Davis. Countercanter put in a bit more stuff in the Roan (horse) article. Apparently UCD had a pretty extensive study even pre-DNA test where they concluded that there had to be such things as homozygous roans and that it wasn't lethal. My guess, and it's just a guess, is that even though roan is dominant, at the same time, it's kind of a weird color that is less popular than big flashy spots or cool-looking dilutions, there just wasn't any real push to breed for it. (Scratching my head trying to think if there's a breed that is predominantly roan and cannot think of one). And yes, there is some sort of thing where sabino (and white markings in general) does seem more vivid and flashy on chestnuts...the bays seem to mostly confine themselves to high white and bald faces, the Budweiser Clydesdales thing... User:Countercanter was trying to explain to me how there is some correlation with chestnut and more white, but apparently what it is is not yet determined. I wonder if it's because chestnut is the most recessive color of them all? The one thing all this stuff seems to have in common is that these genes all seem to hang out in the general vicinity of the KIT locus. I am not clear enough on genetics to understand how all this works, but KIT has a lot to do with many of both the white patterns and roan and even some white markings that don't fall into a spotting pattern. Oh, and speaking of sabino and rabicano, if you want weird, the same dark bay mare I noted above? She's now 30 and getting VERY distinct roaning on her upper neck and forelegs. Most folks say she's just getting old and going gray, but the vet thinks she has a touch of sabino; her sire had a body spot that came and went from year to year, plus he had a huge white snip that I cannot recall if it extended onto his lower lip, but may have. You can see the roaning a little in this photo, which was taken when she was 27. It's more obvious now. Now, of further weirdness, there is ancedotal stuff that blood bays don't get this graying/roaning thing as they age, while dark bays (whatever makes them dark bays) do. What I can tell you is, having owned four bays that made it into old age, it IS true that the blood bays didn't get really any graying to speak of, while the dark bays did. Wonder what's up with that? Montanabw(talk) 17:35, 30 July 2010 (UTC)
- If memory serves, homozygous roan was thought lethal because roan Ardenners had about 33% non-roan and 66% roan offspring. Could be explained if HZ roan was lethal (all roans would be heterozygous, and their offspring would be 25% non-roan, 50% roan, and 25% would be aborted due to lethality, leaving the foals seeing daylight 33% non-roan and 66% roan). I think UC Davis is bold to suggest that tests in one breed are enough to prove something... My money would go on multiple roan genes existing (as with sabino), and on rabicano being located in the same locus. Varnish roan is especially interesting because it 's like "old horse silvering" crossbred with greying... This is just me babbling, so don't bother smacking me with OR accusations or anything >w> Pitke (talk) 18:17, 30 July 2010 (UTC)
- Of course, no one wants to donate the money to do the search for the genes that cause the "weird" colors that aren't a big deal commercially to anyone...sigh. Roan caused by different genes in different breeds certainly possible, I agree we are pretty sure that IS the case with Sabino. I will note, however, that the Quarter Horse is, at heart, kind of a mutt breed (bless them), having their stud book only since about 1945 (and still open to Thoroughbreds). They have lots of foundation stock of unknown breeding, which included a number of Mustangs, a few (known) Arabians, and lots of horses with spots, including (they hate to admit this) Appaloosas. So you probably do have a decent light horse genetic mix just within that breed alone. For all we know, there is a wee bit of draft blood in some of those "unknown" animals -- farmers used to deliberately turn draft stallions out with feral mare herds in some areas to make cheap little work horses. And then the varnish roan is actually part of the leopard complex. There's a ton of them in the Appaloosa to the point that they are not really all that desirable. Montanabw(talk) 18:25, 30 July 2010 (UTC)
- If there's a ton of VR:ns in Appaloosas, they should totally attempt to breed it true and create a new sub-breed or something :3 I'm very fond of the pattern myself. As for Quarters, if they still take TB it means they could introduce Dominant White to their already annoyingly/enviably wide colour gene pool! owo The other option is to wait for a spontaneous mutation of course 9v9 Pitke (talk) 18:37, 30 July 2010 (UTC)
- As far as I understand it, Varnish roan has nothing to do with roan and everything to do with the leopard complex, which is not entirely understood. I don't breed Appies, but my understanding is that even Appy breeders never really know what they're going to get. Sometimes they may have a delightfully spotted foal at birth that "roans out" as an adult. (At least, it's a frequent lament. That and breeding two spotted critters and getting a solid). (Full disclosure: I used to train more than my fair share of Appies, people seemed to figure if I trained Arabs I must be able to train Appies...both breeds too smart for their own good, but in different ways. Arabs just want you to love them. Conversely, if they had opposable thumbs, Appies would join Al-Qaeda! IMHO)(Dana, don't shoot me for saying that! LOL!)
Hey it's me (Pippa); please don't run away screaming (my motives are pure)! I think what possibly may have happened is that the original research was done on animals which were strictly and only 'classic roan', i.e. animals which showed true classic roan type, with no roaning at all in the mane, tail, tail-head (tail-cap), the forepart of the head (i.e. forwards of the 'classic' diagonal line on the cheek), main-body roaning evenly distributed through all the roaned areas with very clear and distinct borders between roaned and non-roaned areas, and no roaning at all in the lower legs, with the 'classic' inverted-V shapes above the knee on the forelimb, etc. etc. In other words, classic roans which always threw the exact same pattern of roaning, generation after generation. And that later studies may well (probably) have included other roaning types of pattern, or mixed roaning types of patterns. In which case, the priginal studies may have been absolutely right in concluding that that particular pattern of roaning (and no other) seems to throw the 2:1 ratio which would normally be associated with an embryo-lethal homozygous form, and the later studies may be absolutely right in concluding that there are forms of roaning patterns which are not homozygous-lethal (in any form, embryo or other). Both studies would, in fact, be right about what they were studying. I think the opnly way that anyone could really 'comprehensively debunk' the original stuydy would be to repeat it using only animals showing the exact-same roaning pattern (classic roan) with no roaning showing anywhere which classic doesn't touch (see above). Only by doing that could we were be sure that we were, in fact, repeating the 'classic roan' experiment, and not conducting an alternative anykinda roan experiment. I don't think anyone has ever suggested that it was anything other than the strictly classic roan which might be a lethal roan. (Would it be an idea to separate-out this roaning bit from its current place in the 4-allele chart section?)(PippaRivers (talk) 18:37, 4 February 2011 (UTC))
OK, to answer it all:
- Dr. Philip Sponenberg just updated his genetics book in 2009. I haven't rounded up the $100 bucks to buy it yet, but the 2006 version is on Google Books. Well worth looking at, even if a bit outdated. He has more interest in the "weird" colors than did Bowling (who was also an Arabian breeder, by the way) and probably is your "go-to" guy for that sort of info. (He's also interested in rare breeds).
- Just know going in that the "it's not 100% certain so how do we KNOW?" argument makes me extremely short-tempered. I'm not going to say it's 100% certain that the sun will come up tomorrow, just a very high probability. Similarly, it is generally impossible to prove a negative (for example, what if Bay is a lethal gene when crossed on silver-dapple-roan-chestnut-tobiano in an Akhal Teke? Just because it hasn't happened yet doesn't mean it MIGHT someday!!) so I think those kind of arguments are also a fruitless waste of time.
- That said, I weigh evidence. And I have been known to change my mind and evolve my thinking (which I think shows in this sandbox).
- My own interest in this area started with having owned an Arabian horse with a genetic disease (cerebellar abiotrophy). My first move over to color study was looking at the color lethals such as lavender foal syndrome and then lethal white. So the lethal color stuff is an area of particular interest for me.
- I've been working on the coat color articles here on wiki for most of the four+ years I've been here, often with the help of people like countercanter, who happens to have very strong background in genetics. I have reviewed a lot of peer-reviewed scientific literature, and while I am certainly no geneticist myself, there is a lot of "old" material out there on colors that is at best wishful thinking, and often just plain wrong.
- The world of equine genetics has been stood on its head since the equine genome was sequenced. As far as I'm concerned, anything more than five years old has to be studied very carefully as it may have been changed by new studies.
- Color terminology varies a bit by nation and region. Also, people like to sell horses by claiming that THEIR horse is some weird color (for example, I've heard of "biscuit duns," "lilac duns," etc...all of which are just cream dilutions for the most part.) What matters is what is going on genetically, not the sales pitch. In the USA, the "mouse dun" and the "blue dun" and the "grullo" (or grulla) are ALL horses with dun dilution over a black base coat. That's it. Just because someone wants to call their silver dilute a "mouse dun" doesn't make it so, it just means they are trying to sell something as something else. End of story. (And I've noticed that color breeders are really bad about this in general).
- Let go of the "classic roan lethal" thing. It was debunked a decade ago in the breed where it most often appears. I know it's hard to let go of certain things we once were sure were true (I'm still suspicious that dominant white is always a homozygous lethal, even though Countercanter tells me it's not proven in some forms, and even the ones where it seems proven have methodological flaws in the studies) and its particularly hard to prove a negative.
- What gets called "roan" is usually either a) roan, b) the leopard complex color called "varnish roan" c) badly-identified sabino, or d) some forms of rabicano (and if you can find studies on rabicano, I'd love to see them! This is the weirdest one of the bunch -- and fascinating!) I have seen "roaning" or "graying" on very old horses too, but not predictably.
- And, obviously, horses can have mixed color patterns from different genes. Usually this is a sign of "mutt" breeding, and thus why really weird stuff is discouraged by breeders. However, sometimes weird colors can be fun. Montanabw(talk) 20:44, 4 February 2011 (UTC)
- Comment on bay/agouti stuff: Other than the "seal brown" test (which has yet to be subjected to peer review, by the way), we haven't fully verified via DNA studies which forms of darkening are a variation on the bay allele and which are overlays that can affect other colors. However, per the discussions with Pitke and others, it looks like seal brown and "wildtype" bay appear to be variants on the agouti allele itself, while "sooty" and "pangare" are totally separate genes that seem to affect many (maybe all) base coats.
- Similarly to wildtype and seal brown, there are a lot of interesting but unverified theories on what causes things like the fleabitten gray or why horses gray at different rates. Be curious to know more about those little allele variations within a broader color family. I'm also very curious about flaxen. Another one no one seems to really understand.
- Getting rid of the sooty/smutty thing by diet is called undernourishment! Everything lightens up if the coat dries up! No mystery there. =:-O Montanabw(talk) 20:39, 4 February 2011 (UTC)
I did not mean to annoy - I never mean to annoy (ever heard the one about "John Doe doesn't suffer from stress, he's just a carrier" ?)(PippaRivers (talk) 04:21, 5 February 2011 (UTC))
That roan thing ..... sorry!
[edit]Hey Montana, I've been (still) obsessing about 'that roan question'. I apologise. You said "Second, the UC Davis "roan zygousity test" is a "real" DNA marker test, which means that it's very accurate: it tests for the presence of several genes that "tag along" with roan almost all the time, but researchers haven't figured out which one is the precise gene that causes roan (it would be like saying, "we aren't certain which house Cousin Vinnie lives in, but we KNOW he lives on the 600 block of Main Street.")"
My lurking-doubt question is this: yup, we know Vinnie lives on the 600 block of Main Street, fair enough. But without being able to pick Vinnie himself out of a line-up of his family, how can we be sure that the guy we have under surveillance is actually Vinnie, and not one of his various relatives Viktor, Virgil, Virginia, Valerie, Vane, Vanessa and co.? They probably all live on the same block, in the same street. And the whole family are all tall, dark and handsome ....
I do apologise for being a right royal pain-in-the-ass :-) Please don't spank me too hard! (PippaRivers (talk) 09:35, 4 February 2011 (UTC))
To expand (I'm too verbose, I know ......) Suppose the only thing on which we can really tell Vinnie apart from brother Vane is that, when Vinnie goes out all on his own, he never, ever leaves any part of his white shirt-tails hanging out. And suppose that Vane often just can't resist having either his shirt-tails, or a white hankie or something, making a little flag around his ass. If we're following a whole family group, and we're spotting a white ass-flag, we can be pretty sure that we have Vane in the group. But when they split up, instead of tailing Vinnie, we accidentally take the other path and end up tracking Vane's movements instead? That's going to create some confusion, especially if someone accidentally tells us that the Vane group is including the Vinnie group, all the time.; What I'm seeing in the 'true breeding roans' in the Hancock Horses pictures is Vane's white ass-flag. It's hard to tell if Vinnie is hidng in the group as well - but we can be darned sure that Vane's there, every time.
Do you follow what I'm saying here? (PippaRivers (talk) 11:30, 4 February 2011 (UTC))
- I don't, but I certainly am enjoying it: do carry on... I want to know where Vinnie was going, and does Vane know? Richard New Forest (talk) 11:54, 4 February 2011 (UTC)
Haha! This is the problem ... what was Vinnie up to? And was Vane covering for him? The biggest problem is that we have a group of 'surveillers' who think that Vinnie and Vane are the same person! Every time they see either Vinnie, Vane (or Vanessa, Viktor, or any of the family .....) they say: "Hey! There's Vinnie!" And, though we've identified a group of 'taggers-along' (we'll call them groupies for now), we don't know whether Vinnie and Vane are so close that they have the same groupies as each other, or whether the groupies we're looking at might actually be Vane's and not Vinnies at all ...... (PippaRivers (talk) 12:14, 4 February 2011 (UTC))
- Well, what we know vis-a-vis the "lethal roan" question you raised at your talk page, is that while Vinnie was once a suspect, he's been ruled out because they discovered that even though the family had a bad reputation, he was actually in Ploughkeepsie at the time and so the bad actor (the lethal gene) was probably, um the one that "framed" him! Or, to put it more scientifically, the KIT locus is a hugely interesting area of research, but so far there are many falsely-accused innocents! Montanabw(talk) 18:54, 4 February 2011 (UTC)
It was Colonel Mustard, on the grassy knoll, with the AK47. Honest. (PippaRivers (talk) 04:12, 5 February 2011 (UTC))
White Leg and Facial Markings
[edit]Do you know if anyone (other than me, lol!) is doing anything on characterising white markings (in otherwise pretty solid-coloured animals) by type? I'm noticing that markings-by-character are tending to run in families here (so handy being able to see a big combination of mum'n'foal pairings, year on year , and knowing who dad's very likely to be :o) ) The clean-edged, clear-cut, mainly horizontal-finish leg markings are one type that seem to carry through the generations, and the speckly, rough-edged, roaned-edged and 'rising to a point' leg markings are also seeming to run through the generations relatively 'true'. Same seems to go for facial markings - clear-edges as opposed to uneven-and /or-roaned edges. And some animals are showing both types in different areas. But each type seems to be distinct in itself, at least on the legs. (PippaRivers (talk) 10:36, 6 February 2011 (UTC))
I'm talking about 'bog standard' leg and facial markings in animals where there's no white anywhere else. In the NF breed, our breed standard forbids white anywhere higher on the leg than knee or hock, and anywhere on the body behind the head, and though animals do occasionally 'fail' and have to be registered in what we call the X-register (their offspring can't be registered as NF, nor can they enter a class for NF's), we actually don't get many which fail from excess white. That sounds very muddled - I hope you can understand it! So I'm not talking about white markings which turn up alongside stuff like sabino & co., but as stand-alone white markings. (see File:SplashTypeLegMark.jpg for a leg marking with splash-type characteristics, and File:SabinoTypeLegMark.jpg for a leg marking with sabino-type characteristics, both coming from this chap here File:FlaxenChestnutNF.jpg who is basically solid-bodied, though this is also the chap with the rabicano frosting lurking in his mae and tail. He also has a few scattered white hairs throughout, and a top-frosty bit of rabicano at his withers, which I shall have to get a pic of (and no it's definitely not a saddle mark, as I've owned him since he was a barely-halter-broke youngster!) And he has nothing more than a few scattered white hairs in the flank region.
Alleles/genes and all that re rabicano; I'm suspecting genes at more than one locus, one or more with multiple alleles, and maybe interacting with each other. Can't think of any other way of accounting for all the various 'rabicanic patterns', specially when you appear to get interaction of more than two pattern-types in one animal.
Rabicano!
[edit]This fascinates me. About four decades of 'field observations' have shown me many things. Far, far too many things, lol!
- No way you can predict which version of rabicano-marking you're actually going to get, guaranteed.
- Many times, rabicano does indeed start at, or be more pronounced in, the flank area. But over here in the New Forest, you are far more likely to get it showing as starting / spreading from the topline than from the flanks. Different 'type' of rabicano?
- Can display as anything from nothing but scattered white hairs with the odd roaned-out patch, to a heavily frosted topline, with almost whited-out manes, striking skunk-tails, frosty rump mantles and 'blankets' (no, they're not appy - appy ain't allowed in the NF breed!)
- It can change intensity, year-on-year and season-on-season.
- It creates some very interesting effects when combined with classic roan
I'm suspecting polygenic and / or polyallelic. Whatever it is, it's going to take some sorting out .... a zillion-many variables! Any takers? (PippaRivers (talk) 11:11, 6 February 2011 (UTC))
- That's interesting, but do explain that dun leopard foal! How?!? Pitke (talk) 18:38, 6 February 2011 (UTC)
Mum was a dun mare (sadly not a Forester, as we seem to have lost the real dun gene from the breed). I think she was a Shettie-cross-summat, going by her general body shape and so on. The mare was covered by a spotted stallion (not allowed on the Forest, as only pure-bred Forest stallions are allowed out there), so anyone wanting to use a non-Forester sire gets mares covered at home and then turns them back out on the Forest. Up in the Penn Common area of the Forest we have all kinds of truly weird-coloured animals turn up, far more non-New-Foresters running up in that area than actual New Forest ponies. The little foal in the same sale pen as the stripy lad came from the same breeder; you can't see in the pics, but it was beginning to blanket-spot-out over the quarters. Needless to say, the spot-stripy chappie sold for about eight times the price than anything 'ordinary' coloured of a similar type went for! (PippaRivers (talk) 19:43, 6 February 2011 (UTC))
See here for a common expression of rabicano here on the Forest: http://en.wikipedia.org/wiki/File:BayRabicanoFrostingSkunkTail.jpg
That dunny-stripy chap ..... almost everywhere you would look for primitive markings was whited-over by his leopard pattern. I think I found just two spots along his topline which each showed just one side of what would have been his dorsal. It would probably have been easier to see if he were clipped out! (PippaRivers (talk) 09:13, 7 February 2011 (UTC))
- All good fun! By the way, be careful with your terminology...best to read locus, gene and allele. For horse stuff, you may want to also read cropout. Over here in the states, many breeds used to refuse registration to horses with too much white, considering it a sign of impure breeding, resulting in a lot of otherwise purebred bloodstock being thrown out of various stud books. However, with parentage verification via DNA, several breeds had to (grudgingly) admit that there were latent color genes in their breeds; sabino and rabicano in Arabians, overo and tobiano (and even leopard!) in Quarter horses, etc... This is the beauty of DNA testing, you pull a bunch of hair, send it to the lab, you can then know parentage and for extra money, details on color genetics. Can get pricey if you want to see if you really have a pseudo double dilute tobiano homozygous smoky cream with masked frame overo, but it IS doable! (Let's see, that would be four or five different tests, plus parentage...) Montanabw(talk) 09:31, 7 February 2011 (UTC)
- 7. Calling sabino splash? Never heard that happen. More likely that people see a flashy-marked animal, mimimun tobiano or splashed white, and automatically think "high white, that's sabino". Sabino-awareness has been well on the rise, and I doubt the general SB/FH/WB breeder (which would make about 80 % of the horses and breeders in Finland :/) would know any other whiteness pattern besides it by name, even tobiano. Not to mention splashed white! Then again, Icelandics are quite popular in here, and at least their breeders should be knowledgeable about Spl. AND then there was this instance with the early spotting pattern study that included Finnhorses among others... they described what goes together with the modern view of Spl, but went and illustrated it with images of sabino Finnhorses. They even went on to call the pattern "Finnish paint" XP Pitke (talk) 16:26, 7 February 2011 (UTC)
- Luckily, having a pseudo double dilute tobiano homozygous smoky cream with masked frame overo (stallion) might turn into being profitable, knowing Americans and their horse breeding antics... I'm supposing you're meaning a genotype along the lines of E_, aa, CRCR, FRfr, To_, with either additional PRL_ or CH_? Pitke (talk) 16:26, 7 February 2011 (UTC)
I think what I was trying to say was that the various rabicano-type patterns seem to be categorisable within themselves (I've been inspecting a mass of them on every round-up). We get: frosty rump mantles with skunk or coon tails with hardly any other roaning; radically topline-frosted animals with extensive white in the mane, very white frosting along the line of the dorsal, and skunk tails (but with little roaning elsewhere); a load with scattered white hairs almost anywhere at all; some with roany-type birdcatcher spots (skin dark, not pink, underneath) and a few white hairs dropped into the tail cap; rabicano patterns overlaying on classic roan patterns (where sire is classic and dam is rabicano, or vice versa) - interesting, this one, as these 'marbledy' types seem to have some of the roaning which you;d expect from a classic missing, usually around the shoulder, but retain the classic-type diagonal cheek borderline and inverted V forelegs very distinctly. So, bearing in mind that sometimes I'm seeing a weird multiple combination of rabicanic patterns from time to time, I'm theorising that there's more than one actual 'rabicano-ish gene' (probably all contained within the KIT area) causing that kind of patterning, and the more-than-one genes may have more than two alleles ......
All good stuff. I do understand the basics fairly well (I think.....). Re sabino and splash, true splash markings tend to have very clearly defined edges, running mainly towards the horizontal along the boundaries, whereas sabino markings have speckly, roaned, indistinct, splodgy, messy edges, often with outspots of colour in the white, and inspots of white in the colour, close to the boundaries. (That's the main way I categorise the splash-type head and leg markings and sabino-type head and leg markings). Sabino-type leg markings often rise to a point, and are also often broken - with a speckledy-edge 'sock' breaking up with outlying extra upward points above, and so on (see File:SabinoTypeLegMark.jpg ).
- Ah! you see, there appear to be two different things called "splash" then -- what you describe as "splash" IS what we call "high white" and usually connect to non SB-1 Sabino. (The famous examples being Khemosabi and Mesaoud in Arabians, who definitely do NOT have "splashed white," though some of their descendants get pretty wild and crazy-looking) What we in the USA call "splash white" is defined by groups like the APHA, and it refers to the spotting pattern where the horse looks dipped into a bucket of white paint, white running "up from the bottom" if you will. Often, a splash white will have blue eyes, often a white head, and there is a link to deafness. Arabians with "high white" do not have this kind of splash white, they have some variant of sabino.
I refer to the white markings as 'splash-type' or 'sabino-type' meaning that their over-all characteristics are what you'd see on splash or sabino markins elsewhere on the body. I'm not going so far as to say they are Spl, or "SB[wildcard character]", it's just a convenient way to distinguish between what seem to be distinctly separate sorts of head andleg markings. Did that make sense? (PippaRivers (talk) 22:53, 9 February 2011 (UTC))
Multiple-Layered Blue
[edit]When it comes to crazy multiple colour layers, you'd have just lerved a cob I once knew (called Blue). I'm just going to nip over to my own pages and grab the descriptipon (I do love copy and paste!)
....[trotting away, ah heck, let's break into canter and kick up the heels]
... [back, tearing up streamers of mud'n'grass whilst sliding to a flamboyant stop]
..... He was a 'gypsy vanner' horse, standing around 145 - 155 cm. He was a strong, cobby build and was reputed to have some Shire in his background, although his ancestry was obviously very mixed. He had a full, heavy mane and tail, and heavy feathering on the lower legs. His body colour including head and ears was primarily blue roan. He had a broad white blaze - extending just beyond the edges of his nasal bones.
Both his eyes were blue. The lower extremities of all four legs were white, with some ermine marks in the white. Where an ermine mark was placed on the coronary bands, his hooves were striped. Immediately above the white lower legs, the colouring turned very dark (almost black) before becoming blue roan. The borderline here was clearly marked and distinct.
The forelegs showed the distinctive triangular points on the black that I associate with classic roan pattern. By the top of the legs (a few inches short of the elbows and stifles) distinct white speckles began to appear in the roan. The speckles merged into blotches as one proceeded upwards, and the majority of his belly area was white. This gradually turned back into blue roan, via the 'splotches and speckles', on his ribs. (The lower quarters and shoulders remained roan.)
Within the roan on his shoulders and neck were a few distinct white areas, surrounded by roan. One was a particularly striking 'zigzag' lightning-flash mark, running down his left shoulder. There was a white patch with speckly edges - shaped a bit like a piece of jigsaw puzzle - on the offside of his neck, running into the offside of his mane. There were also a few elongated black splashes in his predominantly roan areas.
On the top of his quarters the roan faded out into an appaloosa-type blanket, complete with elongated black and blue roan spots and splashes.
The overall effect was one of 'marbling'. He had NO RED HAIRS anywhere at all. His mane and tail were predominantly black, but with a few white sections. (Particularly at the sides of the tail.)
The best guess I can make is that this was a combination of:
- frame gene (indicated by blue eyes, white marks surrounded by colour, etc.)
- sabino gene (indicated by speckles / blotches, white belly etc.)
- leopard complex (appaloosa, indicated by the spotted pale blanket and possibly the dark spots and striped hooves)
- possibly tobiano gene (which could be indicated by the ermine marks in the white on the lower legs)
- classic roan (indicated by the distinctive points to his dark legs before roaning comes in)
- and Rabicano gene (indicated by the roaning to the head and ears, which doesn't occur with classic roan, and the white 'frosting' at the sides of the tail)
- ... all acting on a black base coat. (PippaRivers (talk) 19:00, 7 February 2011 (UTC))
- (Made into a list as it seems you intended to do one). I'll argue with the FR idea. Where would he have gotten that? I've come to understand it's a New World mutation, and the frames in TB would either be result of crossbreeding or a new mutation. And American breeds aren't very commonplace in the UK right? SPL is a known blue-eyes-without-flashy-markings maker, and of course there can be other, unrelated factors too. Pitke (talk) 21:29, 7 February 2011 (UTC)
- I'd have to see a photo. You do see stuff like that in the Paint and Appaloosa world here, also in some Mustangs. Usually a sign that everything but the kitchen sink is in there genetically. Frame is not an "American" mutation, it traces to Spanish lines, but the "frame" you describe could also be the US version of splash. There are frame overos in TBs, but I think they are all US ones from obscure lines, and frankly, if you want my personal opinion I think someone just snuck a Quarter Horse into the woodpile in hopes they'd get a better sprinter and didn't tell anyone! (people sometimes cheat and lie? Never!!) :-P Applying Occam's razor (the simplest solution is apt to be correct), said Quarter Horse may also have masked frame and hence a few generations down the road, the cropouts appeared. Other than the freaky frame TBs, all other frame horses go back to various Spanish colonial lines, so I personally don't buy the mutation theory. (though maybe it was a spontaneous mutation, who knows??) Montanabw(talk) 03:39, 8 February 2011 (UTC)
The "frame' thing - it was the white-surrounded-by-roan markings on his shoulder and neck that got me thinking frame (along with the blue eyes, though I know that they turn up for other reasons, too). Particularly the lightning-flash mark; the edges were really, really clear, not like the messy sabino-type stuff. Showed up very well when he had a bath and you could see the skin colour underneath. (ThatPeskyCommoner (talk) 11:38, 11 February 2011 (UTC))
We have all kinds (and I do mean all kinds) of stuff over here. Starting with the pre-Roman trade from Europe (including the Med), and going on from there. Archeological sites have turned up some really ancient evidence of widespread trade between ancient Britain and elsewhere. I have no pic of Blue (sob); I knew him about (erk!) 35-40 years ago; which means that even if I had a pic, it would most likely be black and white anyway! The British gypsies bred almost exclusively for 'pull four times its weight' combined with 'how pretty (crazy) a colour can we actually get in an animal', so anything unusual crossed with anything else unusual was pretty much the norm, lol! Mutts can have their uses, too. I know, I am one. (PippaRivers (talk) 16:21, 8 February 2011 (UTC))
Flaxen
[edit]Here's another for you: flaxen! I'm sure there's more than one type. We have the 'seriously pale' flaxens of the Haffies, but we also seem to have 'half-flaxens' turning up on the Forest, with manes and tails that are red-gold rather than true blond; distinctly paler than the body coat but not really pale enough to call flaxen. I haven't yet had time to go inspect all their offspring, or all their parents, but sometimes they'll throw a 'real-pale-flaxen' foal. And what did you think of my non-flaxen flaxens? The manes and tails are definitely diluted compared to the body colour, but they ain't what I'd call 'proper flaxen'! (PippaRivers (talk) 19:41, 7 February 2011 (UTC))
- Finnhorses have a lot of those too. We are used to see almost any coloured manes of chestnuts, ranging from dark liver on dark sorrels to bright natural white flaxen to steel grey "hemp mane" as we call it. Now I'm interested, have you encountered any grey-maned/tailed animals with no evidence of rabicano or greying? Pitke (talk) 21:29, 7 February 2011 (UTC)
And how do you fancy a totally random non-equine pic of the boa constrictor having a bath? (Her nickname is Cuddles ......) (PippaRivers (talk) 20:15, 7 February 2011 (UTC))
- IMHO, your "non-flaxen flaxens" in the photo ARE flaxens. At least when it shows up in Arabians, that's what we call it...Flaxen is simply a true chestnut (red to liver) with no diluted body color but a light mane, whether it's white-white or cream-white or yellowish-white, it's flaxen, end of story (just like some palominos are really light creamy colored and some are more golden, it's all the cream gene). The gray mane/tail thing is pretty much thought to be rabicano here, though if you look at the Nowegian Fjords, who appear to be 100% dun, the significant light guard hairs in the mane and tail that are characteristic of dun might account for some of the mix. (Apparently all duns have the white guard hairs, they are just so very prominent in the Fjords). Montanabw(talk) 03:39, 8 February 2011 (UTC)
- So do we think that we have more than one 'flaxen' variation? I've heard tales of flaxen being recessive, and I daresay there's a version which is, but I do think that there's a (more than one ?) version(s) which are 'incomplete dominant' (just like cream is). And sometimes we're getting a flaxen which touches only the mane, or only the tail, and one which doesn't touch the lower leg, and one which does (no, not pangare, as no pangare dilution around the belly and muzzle), etc. (PippaRivers (talk) 09:03, 9 February 2011 (UTC))
- I was there and this critter had no non-red hair on her body anywhere. Forelock is a smutty brownish shade. Pitke (talk) 09:33, 11 February 2011 (UTC)
- I'd be guessing a top-dusting version of sooty, combined with flaxen. I have a yearling chestnut colt with both sooty and flaxen all mixed up in his mane (going to try to 'stuff-it-with-sugar-beet' experiment on him to see how darkly I can get his body-coat to 'sootify'. So far it's worked on every chestnut-with-sooty that I've done this on!) (ThatPeskyCommoner (talk) 19:54, 12 February 2011 (UTC))
- We need to create an article on the flaxen thing, I suspect. ON the list, hasn't happened. If someone else starts it, give me a shout and I'll add it to the color template and do any cleanup. Sponenberg is probably the only legitimate source out there on anything, the 2006 edition of his book is in google booksMontanabw(talk) 00:57, 13 February 2011 (UTC)