Ôîðóì » Breeding » Color genetics » Îòâåòèòü
Nina: I think it would be very interesting to place Collies in the overall dog color genetics story. There were already some discussions on white dogs, so it should be a good subject to start. Sorry about my not-so-good English, I know I should probably find the original texts and paste them here... but this is shorter and easier... There are 3 basic ways the dog can be white: - Phaeomelanin dilution - Merle - Spotting Phaeomelanin dilution is said to be caused by the Chinchilla Allele. It turns red pigment (phaeomelanin) into light red, cream or pure white. Here's an example of how it works... Many white dogs - like Samoyed, Westie, Maltese etc... - are in fact genetically red dogs. Their eyes, eyelids and lips are always dark. They should not have trouble hearing, because (although they appear white) they don't lack pigmentation. This has nothing to do with Collies, so let's move on... Merle dilutes black pigment (eumelanin) randomly into silvery-blue with black splashes. A dog with one copy of that gene will have normal merled coat. With two copies, the result is some to most of the coat turning white due to the lack of pigment. Deafness or blindness can sometimes occur, but they can't be inherited separately from the lack of pigment caused by two merle genes. Normal heterozygous merle dog should never have any more health trouble than any other color. Merle was already heavily discussed here, so I believe this will be enough... Spotting is much less discussed, and in my opinion incredibly interesting. It is the gene that causes typical Collie white markings. It also appears in other breeds, in greater or lesser degree - Bernese, Basenji, Tornjak, Foxterrier, Bullterrier, Dalmatian, Dogo Argentino... White areas on these dogs contain no pigment... so theoretically, these white headed dogs have a chance to be blind or deaf.... however, that chance is not as big as in double merles, because spotting gene acts less randomly - it "takes care" of the important areas (eyes, ears...), making them least probable to lose pigment cells. This photo illustrates pigmentation pathway in a mouse embryo (same applies to dogs) photo courtesy of G. Barsh, Stanford http://homepage.usask.ca/~schmutz/pathway.html The melanocytes are migrating down from the neural crest derived cells along the spinal column and brain. Eyes and ears almost always have some pigment, and last places to recieve pigment cells are toes, chest, tip of tail, tip of nose... Spotting gene roughly determines when will this migration stop. For example in Dogo Argentino it stops almost immediately, leaving the whole dog white. In Labradors it goes all the way, leaving maybe a small spot on the chest or toes. Collies are somewhere in between. Besides the spotting gene, white markings are also influenced by external conditions. For example - if the mother has some sort of trauma in pregnancy that disrupted melanocyte migration, it can happen that puppies have more white markings than usual. That's why we can never predict exact amount of white markings some parents can give.
Îòâåòîâ - 43, ñòð: 1 2 3 All
carluke: any pictures of her body? she really just looks like a mismark merle to merle to me. We have roughs with white body markings (white factors). On the weekend just gone I saw a Rough merle with a similar amount of white face marking and half her showside white splashed but she was definately a merle. I have never hears of a Harlequin either. Cheers Kate
Spiritwind: carluke wrote: I have never hears of a Harlequin either. There are only a select few bloodlines in the US and Canada that have TRUE harlequin blue merles. Actually the pictures I posted above are 3 generations of harlequins. Grand Mother, Mother and Daughter. There is already DNA tests on Collies in the US to test to see what coat color they are genetically, last I heard they were currently working on a DNA test for harlequin to see if its TRUE harlequin (like in danes) or just a different shade of blue merle. Info on the Harlequin gene in Danes: "Harlequin is a completely unique modifying gene which affects only dogs with the merle gene. It turns the areas between the dark patches into pure white (occasionally with some grey ticking or patches). This means a blue (black) merle will become white with black patches, because all the grey in its coat is turned to white. What is even more interesting about this gene is that it also affects phaeomelanin (red), not just eumelanin (black, liver, blue, isabella) like other merle modifiers. That means that a sable dog with the merling gene won't just be affected on the parts of its coat that are black (tipping, mask etc), but the whole of the coat will be harlequin. It will become what is known as a "fawnequin" - tan (sable) patches on a white base, with black patches where it would have shown black merling. The patches on the fawn section of the dog are located where the dog would have had black patches if it had been a solid blue (black) merle." From what I understand, this "harlequin" coloring in Collies just sort of happens. You can breed a regular blue merle to a tri-color and get some puppies that look harlequin, and some that look like regular blue merles and you can breed a harlequin blue merle to a tri-color and get regular blue merles...
marakoopa: carluke wrote: any pictures of her body? she really just looks like a mismark merle to merle to me. We have roughs with white body markings (white factors). On the weekend just gone I saw a Rough merle with a similar amount of white face marking and half her showside white splashed but she was definately a merle I will look for some pictures of her just born. But still have to find out how to place them here.
Mabinogion: hee janet dat is hier gemakkelijk ,zie je die icoontje hierboven ,dan zie je een mannetje daar op klikken en dan kun je een foto selecteren uit je eigen bestand ,dan uploaden ,staat wel in het russisch,dan zie je allerlei url van de foto en daar je er een van gebruiken ,het beste is diegene die begint en eindigt met IMG. snap je het? ik gebruik deze ook voor ons eigen forum ,erg handig i was just telling how to put the photo's here!
marakoopa: Pictures of the puppy, I hope you can see them. Spiritwind wrote: don't know if they have the DNA tests in Europe, but in the US and Canada they do have DNA tests to determine the genetic color of a Collie. It would be interesting to have this puppy DNA tested to find out what color she is genetically! To test the puppy I will have to ask the owners. I don't know if they want to test her. But I am thinking about testing my bitch. If she really is tri-colour of geneticly blue-merle. Janet
Mariska: Hello to all, My name is Mariska and I am the owner of the blue merle male Zap and It's Done Fantazija and I think that he does not have the white factor we are talking about. His other litters show no sign of it. That is why Marakoopa's Baringa is so interesting. You can see puppies from the other litters if you use this link: http://members.chello.nl/c.berkelmans1/zap/offspring.htm Greetings, Mariska
Spiritwind: marakoopa wrote: To test the puppy I will have to ask the owners. I don't know if they want to test her. But I am thinking about testing my bitch. If she really is tri-colour of geneticly blue-merle. I think its a good idea to test your bitch. You just never know. I have seen some "cryptic" blue merles, that are VERY hard tell are blue merles, except for a very small spot of merle hidden somewhere. IF she comes back as a tri-color though, I personally would test the puppy, just to know! I would want to know, because she really does not look like a color headed white at all. She looks like a double dilute. Mariska wrote: Done Fantazija and I think that he does not have the white factor we are talking about. His other litters show no sign of it. I agree.. I don't think either parent of this puppy looks white factored, though I do know of someone who has a white factored dog who does not appear white factored-- no white on the legs, and a broken collar. She did the color DNA test and it was proven through there it was a white factored. However since none of the other puppies sired by your dog look white factored, I doubt he is! The dogs above are Double Dilutes These are Color headed whites
Mariska: Hello to you all, My name is Mariska and I am the owner of the blue merle male Zap and It's Done Fantazija. I doubt he is white factored. I believe he is not. He has given 3 other litters and none of his other offspring looks white factored. In the two litters in the Mabinogion kennel some dogs have very little white. The offspring in the Midden Aarde kennel has a bit more white, but not as much as Midden Aarden dogs often have....... If you look at the Marakoopa kennel's pages you can see a brother of Baringa who nearly has not any white in his coat (Marakoopa's Bykool). Fjurdy's offspring do not look like they are white factoren either, I think..... You can see Zap's offspring if you use this link: http://members.chello.nl/c.berkelmans1/zap/offspring.htm Could it be that Baringa is just a case of "nature doing it's own thing"? I don't know.... I would like to hear your opinions! Mariska
Mariska: OOPS SORRY! I thought my first message did not came through so I posted a similar one Sorry Mariska
Nelson: Hi all, I saw this very interesting topic and I would like to ask about my puppy - Anamur Grenay. She is like tricolour, but not black. Some pictures after born on my website - http://www.grenay.cz/odchovy/a/a_9.4.08.html Here you can find pictures from her 1 year celebration: http://vanourek-bordercollie.cz/smecka_2009/skoleni_kolie_18.4.2009.htm (this is all pictures of whole litter and my little Lili) here is direct her pictures: http://img3.rajce.idnes.cz/d6/1/1948/1948227_260ceab53eb91cc931572577310eaae2/images/kolie_18.4.2009_31.jpg http://img3.rajce.idnes.cz/d6/1/1948/1948227_260ceab53eb91cc931572577310eaae2/images/kolie_18.4.2009_32.jpg http://img3.rajce.idnes.cz/d6/1/1948/1948227_260ceab53eb91cc931572577310eaae2/images/kolie_18.4.2009_14.jpg I discussed about it with many people, but noone know how it is caused. She is from blm x tric mating, her mother is tricolour (after blm x tric parents). I got some ideas from other people like that she is cryptic tricolour, or that she has grey collie syndrom or some liver problem. But grey collie syndrom should looks other in puppy age, for liver problem she has vet examination and there is no problem, about cryptic tricolour I don't know what it is. Now I plan to mate my girl (mother of this strange coloured puppy) with tricolour boy. Do you know about some laboratory in Europe, where is possible to test DNA for knowing true colour of her?
Spiritwind: Nelson wrote: Hi all, I saw this very interesting topic and I would like to ask about my puppy - Anamur Grenay. She is like tricolour, but not black. Very interesting. I will say that your dog does not have gray collie syndrome, there is a test for this available now, so you could test just to make sure, but collies with gray collie syndrome do not look like your dog, plus they don't typically survive to adult hood. You should check out info on the "Maltese Blue" Its VERY rare but has been known to pop up here and there. It dilutes the black of a tri-color to a similar color as your dog. Here is a link related to the "Maltese Blue" coloring in shelties. Maltese Blue Color This coloring was talked about a lot on another collie forum I go to. I have to leave for work in a few minutes but I'll write more later on. Here is info on Gray Collie Syndrome. To my knowledge there is only one Gray Collie Syndrome Collie who has survived to adulthood and that was due to her being sent to a be part of a university medical research lab, where they were working on a treatment for a similar disease seen in people... but the dog was was basically cured of the disease and now lives in normal happy pet life... Gray Collie Syndrome Without this treatment she would have died.... As far as a cryptic tri-color.. to my knowledge there is no such thing.
Nelson: Spiritwind Wow, thank you very much, it looks really really like that our Anamur is maltese blue, when I saw the pictures of sheltie puppy that's it. And the signs, which are there written....it is 100%right - she is whole body same coloured, she has ligther eyes, but not with blue, more browngreen, and her nose is dark but not absolutely black. Great, so I think the mystery after more then one year is unriddled Thank you very much and I would be really gratefull if you put here more information about it (or to my email - firstname.lastname@example.org). Thank you!!!
MacGee´s: Very interesting topic! Now speaking of shelties.. I have once seen a really black tricoulour sheltie, that showed no signs of a blue merle colouring anywhere in his body, but one of his eyes was light blue and it had always been like that. Unfortunately I can't remember if he was from a blm - tri mating or if one or both his parents were bi-coloured. But he surely looked interesting! Do you think that the sheltie could've been cryptic?
Spiritwind: MacGee´s wrote: Now speaking of shelties.. I have once seen a really black tricoulour sheltie, that showed no signs of a blue merle colouring anywhere in his body, but one of his eyes was light blue and it had always been like that. I doubt he was a cryptic, but its certainly possible. Shelties do have a bit more colors that pop up every once in a while, than Collies do. Probably because of the other breeds used to develop the shetland sheepdog. Some sheltie breeders I know had a litter earlier this year that was all sables, BUT had one sable puppy with 1 blue eye. It was NOT a sable merle. Both parents were Pure for sable, sables... I really have no idea what it was, or how it happens, but this dog had no merle in him. I know in Border Collies, you can get black and white BC's with blue eyes as well, that have no merle in them.
Spiritwind: Nelson wrote: Thank you very much and I would be really gratefull if you put here more information about it (or to my email - email@example.com). Thank you!!! Nelson, here is more info on the Maltese color http://www.ashgi.org/color/dilute_aussies.htm as seen in Aussies. One of the Collie e-mail lists I'm on, people are actually talking about Maltese and Harlequin coloring. Someone just posted a picture of their rough sable merle, that appears to be a harlequin sable merle. This person says they also have some Maltese tri-colors, described looking very much like your boy in the photos above...
Nina: Back online... Marakoopa, I've seen your white girl before, she is very interesting I believe she's a harlequin. Spotting (white factor) would cause different patterns, especially on the head. Her white areas are exactly where normally would be blue, her tan points are intact, there is much black on her body, but almost no blue.... spotting wouldn't do that, and neither would double merle.... plus I don't believe her mother is a cryptic merle. Here is a Finnish Rough Collie I also believe is harlequin. Parents are also tri & BM, and her color is pretty much like Kyra's http://koti.mbnet.fi/cesamen/omamansikki.html Here is one possible theory on harlequin inheritance... http://home.rcsis.com/daneaffr/colinher.html We can't know if it's 100% true, but I believe harlequin gene(s) can "hide" in non-merle dogs, and show up when combined with merle. That would probably mean Kyra got it from her mother's side. Theoretically, some of her tricolor siblings and half-siblings from Fjurdy's first litter could produce the same color when mated to merle. Now speaking of shelties.. I have once seen a really black tricoulour sheltie, that showed no signs of a blue merle colouring anywhere in his body, but one of his eyes was light blue and it had always been like that. It might be spotting... especially if there is a wide blaze on the head. I also know a few Borders with blue eyes and no merles in pedigree for generations... this one for example. http://bordercollie.pedigre.net/details.php?id=947 I think in this case spotting is a good explanation, but if there is no white blaze it's probably something else... maybe the same gene that causes Husky eyes to be blue...? I don't know much about it, but sounds possible...
MacGee´s: Nina, the sheltie I was talking about earlier didn't have a blaze. Wish I had taken a photo of him!
Nina: Then it's something else. Maybe it's really the same thing as in Huskies...? Huskies are all non-merle dogs, usually with very little white spotting (most of their white parts are not spotting, it's tan + phaeomelanin dilution... something like Samoyed... skin is fully pigmented). Their eyes are blue thanks to the separate gene, not related to coat color. Here is an excellent website where you can read more http://abnormality.purpleflowers.net/genetics/eyes.htm
Spiritwind: MacGee´s wrote: Nina, the sheltie I was talking about earlier didn't have a blaze. Wish I had taken a photo of him! Nina wrote: Then it's something else. Maybe it's really the same thing as in Huskies...? Huskies are all non-merle dogs, usually with very little white spotting (most of their white parts are not spotting, it's tan + phaeomelanin dilution... something like Samoyed... skin is fully pigmented). Their eyes are blue thanks to the separate gene, not related to coat color. Here is an excellent website where you can read more http://abnormality.purpleflowers.net/genetics/eyes.htm As I said above a while back, I do believe shelties have some other gene that can change eye color. Sheltie breeders/handlers I work for had a all sable (NON Merle) litter earlier this year and one puppy had a blue eye. These puppies were NOT merles, matter fact both parents were pure for sables... from a long line of sables. As far as border collies go, I have seen solid black border collies with blue eyes. It really doesn't necessarily have anything to do with the white blaze on the dogs face...
Spiritwind: And yes... from everything I have read, Harlequin pattern is ONLY expressed in merled dogs, however non-merled dogs can carry the gene for it.
ïîëíàÿ âåðñèÿ ñòðàíèöû