SamS Posted July 31, 2012 Report Share Posted July 31, 2012 Hello to all! I am new to the boards and I am very interested in genetics, so I will probably be writing many threads about coat color genetics. I understand that in merle to merle breedings in border collies, 25% of the puppies will be double merle (and usually blind and/or deaf). My question is: Does the merle gene in other breeds of dogs (such as pomeranians and catahoulas) cause the same health problems? I ask this because, when searching for more information concerning merle genetics, I came across this website: http://www.donabney.com/issue_merle.php This site belongs to a catahoula breeder who commonly breeds merle x merle litters. She says: Since 1994 I have been breeding merle to merle as a part of my breeding program ... When I first started the merle to merle program, my deafness ratio was about 25%, and still well below the average. It now averages below 4%. It has been reduced simply by studying the litters instead of just choosing a male or female to breed based solely on their colors or attributes alone. I don't understand how studying the litters can lower the deafness ratio by 21%. Could someone clarify this for me? She also says: It has long been thought that double merle was the cause of the deafness in the Catahoula; however, numerous double merle breedings have resulted in a complete litter of double merle puppies that were colored and without deafness. This gives way to the thought that the parents were cryptic or near cryptic merles. Could it be that the fearful breeding of double merle is not as dangerous in the Catahoula as it is for other breeds? It appears to be so. Is merle to merle breedings in Catahoulas produce different results than merle to merle breedings in border collies? Also what is a "near cryptic merle"? Thanks P.S. Please note that I am not trying to bash this breeder or condemn her breeding practices. I simply am trying to gain information. Link to comment Share on other sites More sharing options...
Pam Wolf Posted July 31, 2012 Report Share Posted July 31, 2012 maybe Cat breeders chalk up the lack of hearing as just 'breed stubborness" I hear all sorts of excuses for dogs going deaf (in BC's) and we now have a real problem in the breed (yes even in the working lines) Hide your head in the sand and you won't notice the sandstorm Link to comment Share on other sites More sharing options...
SamS Posted July 31, 2012 Author Report Share Posted July 31, 2012 maybe Cat breeders chalk up the lack of hearing as just 'breed stubborness" I hear all sorts of excuses for dogs going deaf (in BC's) and we now have a real problem in the breed (yes even in the working lines) Hide your head in the sand and you won't notice the sandstorm That makes sense. If I may ask, what are some of the excuses about border collies going deaf? Link to comment Share on other sites More sharing options...
juliepoudrier Posted August 1, 2012 Report Share Posted August 1, 2012 I don't understand how studying the litters can lower the deafness ratio by 21%. Could someone clarify this for me? Sure. First you breed two merles. Then you cull all puppies in the litter that are deaf and/or blind and/or miscolored. You then do your statistics on the remaining puppies, most of which are perfectly normal (since of course you got rid of all the ones who weren't normal and didn't have the sense to die right away). Voila! You have singlehandedly lowered the statistical rate of deafness in merle-to-merle breedings. J. Link to comment Share on other sites More sharing options...
mtnfrank Posted August 1, 2012 Report Share Posted August 1, 2012 Let's first look at the second argument: "some litters of merle X merle don't have any deaf pups". That statement shows that the person doesn't understand statistics and thus genetics. Assuming a pup has 25% chances of being deaf with a merle X merle breeding, that doesn't mean that in a litter of 4 pups there will be one deaf one. Each pup has an independent probability of being deaf. Thus a litter of 4 pups will have a probability 0.75*0.75*0.75*0.75 = 31.6% of having no deaf pups, roughly one in three chance. Even with litter size of say 8 pups there would be a 10% chance of no deaf ones in the litter. Now let's look at the second argument, AFAIK (and I'm no researcher on the subject) the link between merle and deafness is not quite fully understood yet. AFAIK, it is not likely that the merle gene causes deafness but rather that the presence of the gene merle has a high correlation of being associated with deafness. It is thus possible that someone could note that other gene expression reduces the probability of deafness and thus 'disassociate' the merle gene from the deafness. But I would think it is highly unlikely that someone could come unto that by chance and by 'observing the litter' when serious geneticist are still investigating the topic (google Merle Allele deafness for a few articles). But, given how many different genetic problems there are with the merle allele, http://en.wikipedia.org/wiki/Merle_%28dog_coat%29, breeding double merle is just irresponsible. But oh the flashy colours (on the dogs and the dollar bills)... Link to comment Share on other sites More sharing options...
Gloria Atwater Posted August 1, 2012 Report Share Posted August 1, 2012 For what it's worth, I've also heard that the merle in Catahoulas somehow is different than that in Border Collies and Aussies. I've no idea why this was claimed, maybe it's supposedly the way the coloring is genetically coded, less white or something? Has anyone heard about that or has anyone any ideas? Or that it just poppycock, and merle is merle is merle? (Feels mildly stupid for even asking.) ~ Gloria Link to comment Share on other sites More sharing options...
Pam Wolf Posted August 1, 2012 Report Share Posted August 1, 2012 That makes sense. If I may ask, what are some of the excuses about border collies going deaf? Ear infection (plausable), head trauma (plausable), shot a gun over the dog (why aren't you deaf?). he just doesn't 'listen' too good but he's a good worker so we will breed him-he won trials when younger. Link to comment Share on other sites More sharing options...
SamS Posted August 1, 2012 Author Report Share Posted August 1, 2012 Thank you all for your replies. Julie- Is it common to cull puppies with defects? I assume that people who are willing to chance having blind and/or deaf puppies must not care too much for the puppy's well being. mtnfrank- Thank you for the clarification. However, I still do not understand the breeder's reasoning in this quote: This gives way to the thought that the parents were cryptic or near cryptic merles. Is that even related? It seems to me that the breeder is saying that as the amount of merling decreases, the chance of genetic defects also decreases. Gloria- I am assuming that the merle coat patterns affects all dog breeds in the same way, but perhaps merle in catahoulas is different. Link to comment Share on other sites More sharing options...
SamS Posted August 1, 2012 Author Report Share Posted August 1, 2012 Ear infection (plausable), head trauma (plausable), shot a gun over the dog (why aren't you deaf?). he just doesn't 'listen' too good but he's a good worker so we will breed him-he won trials when younger. Thank you for clarifying that. Isn't there a test for evaluating deafness? Link to comment Share on other sites More sharing options...
Laurelin Posted August 1, 2012 Report Share Posted August 1, 2012 She also says: Is merle to merle breedings in Catahoulas produce different results than merle to merle breedings in border collies? Also what is a "near cryptic merle"? Thanks P.S. Please note that I am not trying to bash this breeder or condemn her breeding practices. I simply am trying to gain information. A near cryptic to me would be a dog that has very minimal merling. Cryptic would be a dog that is genetically merle but phenotypically 'normal'. You can't look at the dog and know it is merle. My friend's border collie's sire is an ee red (aussie red)and thus has no visible merling. However, he threw merle pups therefore is genetically merle. I don't understand her point there though. If you breed two visible merles, then neither parent is cryptic. For what it's worth, I've also heard that the merle in Catahoulas somehow is different than that in Border Collies and Aussies. I've no idea why this was claimed, maybe it's supposedly the way the coloring is genetically coded, less white or something? Has anyone heard about that or has anyone any ideas? Or that it just poppycock, and merle is merle is merle? (Feels mildly stupid for even asking.) ~ Gloria I have heard that and have seen the study in Catahoulas. That same website had shown pups that look solid but then supposedly tested to be merle. From what I know though, the test for the merle gene was invalidated a few years back. I was under the assumption there was no test for the merle gene. I've heard people say this primarily in Catahoulas, koolies, and then working line aussies. The theory is that darker colored merles with both a darker, more muddied base and then with less white will throw double merles that are also 'less white'. So shelties, show type aussies, etc bred with Irish spotting (often called flash) would have more issues with double merles being born with high amounts of white. The problem I have with this is that I have seen defective double merles in all these breeds. I've seen pictures of koolie litters that have puppies that have a lot of white on them and wonder if those pups are not hearing/sight defective. I've personally known deaf catahoulas, and a deaf and blind aussie who had totally nonfunctional, tiny eyes. It's impossible to know what gets culled too or to have people be honest about what they produce. Maybe the risk is just less than if I were to breed two shelties? I am not sure. But there is still a risk based on the dogs I've seen. I think it's safest to say now until we know for sure that merle works differently in certain breeds or circumstances, to assume it works the same. I just do not understand the mentality of people that do these kinds of breedings. It's potential health issues that are 100% avoidable. I apologize, I have no spellcheck on this computer. Link to comment Share on other sites More sharing options...
juliepoudrier Posted August 1, 2012 Report Share Posted August 1, 2012 Julie- Is it common to cull puppies with defects? I assume that people who are willing to chance having blind and/or deaf puppies must not care too much for the puppy's well being. Sorry Sam, I was being completely sarcastic. I have no idea if people routinely cull pups that are defective as a result of their irresponsible breeding practices. But it is a plausible theory for how she came up with her statistics.... J. Link to comment Share on other sites More sharing options...
mtnfrank Posted August 1, 2012 Report Share Posted August 1, 2012 Statement can't be understood because it is not fully logical. One can understand his flawed reasoning to get there but the reasoning remain flawed. Catahoula association is looking into gathering more data on Merle-Deafness according to this: http://www.cobradog.com/merle-expression-deafness.php Note the specific statement about 'no culling allowed to participate in study', which makes one infer that culling is not uncommon. Obviously I don't know all the latest research but reading this paper: http://www.lsu.edu/deafness/StrainMerleJVIM2009.pdf One can see statements such as: "Of the double merles, only 3 of 29 Catahoulas were affected (10.3%), whereas 2 of 3 Australian Shepherds were affected (66.7%). From the total non-Catahoula MM population of the present study, 7 of 11 were affected (63.6%), suggesting a possible difference between the Catahoula and other merle breeds for merle effects on hearing. This finding is not surprising because most double-merle Catahoulas are heavily pigmented compared with double merles of other breeds." A couple things to note: - it is plausible that less phenotype merle (and by extension ghost-cryptic merle) is associated with not as much hearing loss (that's a reasonable assumption) - BUT there is not enough data to support the theory at this point, the paper has VERY small sample size and thus the use of the "possible". Not only that but without identifying genes that cause deafness then it is all guesses unless one starts to get very large sample size. And the paper says so: "Also, the impact of the merle allele on auditory function may vary with breed (as also is the case for piebald breeds) as indicated by the differences between Catahoulas and Australian Shepherds. Based on unpublished observations (GMS), the collie-type breeds (Collie, Sheltie, and Border Collie) appear to be more affected by deafness than some other breeds such as the Catahoula. However, larger numbers of BAER-tested and genotyped subjects will be required to determine whether or not significant breed differences exist." So evidence is inconclusive at best for now. So yes Catahoula MAY be different and less visible merling MAY be associated with less deafness but we don't know for sure. Given how many other problems Merle X Merle have, why breed for them? And absurdly, if you breed "Merle that are as little Merle as possible" why not simply breed non-merle to start with? And even say that you can get a Merle X Merle that has a lower probability of deafness... how does one do that? Inbreeding? That can cause a whole lot of other undesirable traits to come out while trying to root out a bad one. Link to comment Share on other sites More sharing options...
SamS Posted August 1, 2012 Author Report Share Posted August 1, 2012 Laurelin- Thank you for the clarification. It seems to me that this theory you mention: The theory is that darker colored merles with both a darker, more muddied base and then with less white will throw double merles that are also 'less white'. is simply a way for double merle breeders to justify their merle x merle crosses. I agree with you that people should not breed merle x merle crosses. It makes me sad that people will sacrifice the health a well being of the dog to attain a specific color or look. Link to comment Share on other sites More sharing options...
mtnfrank Posted August 1, 2012 Report Share Posted August 1, 2012 Laurelin- Thank you for the clarification. It seems to me that this theory you mention: is simply a way for double merle breeders to justify their merle x merle crosses. I agree with you that people should not breed merle x merle crosses. It makes me sad that people will sacrifice the health a well being of the dog to attain a specific color or look. Yes! Link to comment Share on other sites More sharing options...
juliepoudrier Posted August 1, 2012 Report Share Posted August 1, 2012 Given how many other problems Merle X Merle have, why breed for them? And absurdly, if you breed "Merle that are as little Merle as possible" why not simply breed non-merle to start with? Short answer: people love the color, and I believe it may be part of the breed standard for the Catahoula. Of course that begs the question of why a standard would be created/accepted that in itself would encourage less than stellar breeding practices, but when has paying attention to good breeding practices ever stopped anyone? Do you remember the thread on this forum not long ago about the winning collie at Westminster(?) whose sire was a double merle? J. Link to comment Share on other sites More sharing options...
mtnfrank Posted August 1, 2012 Report Share Posted August 1, 2012 Short answer: people love the color, and I believe it may be part of the breed standard for the Catahoula. Of course that begs the question of why a standard would be created/accepted that in itself would encourage less than stellar breeding practices, but when has paying attention to good breeding practices ever stopped anyone? Do you remember the thread on this forum not long ago about the winning collie at Westminster(?) whose sire was a double merle? J. I know, it was a rhetorical question. The double merle discussion was here (linking for convenience): http://www.bordercollie.org/boards/index.php?showtopic=32886 This is why I really have a problem with breed standards. IMHO breeding should done with health as the most important criteria -if not issues will compound over time-, temperament as the second most important and then, for working breeds, work ability. For BC, one can argue that work ability requires good health and temperament and makes them all related but that doesn't mean constant vigilance is not required to ensure inbreeding doesn't creep up. It's one level of danger to breed for looks (fluff, tipped ears, whatever) because it increases potential genetic issues from reduced gene pool overtime. But it's another level all together to knowingly breed genetic defects for arbitrary aesthetic reasons, or fancy. Small victory lately, I was able to steer someone away from buying a merle mini-aussie from a place that had some puppy mill red flags. Problem is that my friend had no idea about merle or puppy mills, she just liked the colour and the price. Hence a market for merle X merle. Link to comment Share on other sites More sharing options...
Laurelin Posted August 1, 2012 Report Share Posted August 1, 2012 I would be hesitant to call it due to breed standards. It is done in some show lines (shelties, danes, and collies I know of) but Koolies and Catahoulas are working breeds. I don’t know if koolies have a standard at all. In all breeds I know of that are merle, doubles are DQ’d from showing. I think a lot of it is tradition and the fact that people that were developing these breeds had a poor grasp of color genetics. I see breeders that still don’t seem to understand basic color genetics in all breeds. Heck my own dog is registered as a red and white when she’s a sable. I’ve tried to explain to the breeder why she’s sable and it hasn’t worked. I think people in the day favored these colors without realizing it was breeding the colors together that was causing issues. In a couple cases they were trying for an all merle breed. But they didn’t know merle worked differently than creating a line of all red setters. I still see that kind of misinformation perpetuated. Link to comment Share on other sites More sharing options...
SamS Posted August 1, 2012 Author Report Share Posted August 1, 2012 I know that aussie breeders originally tried to create an all merle breed, but obviously it did not work out. I believe that the majority of the merle x merle crossings are due to the public's perceptions of what makes an attractive pet. Many people prefer a flashy looking merle to a black tri. Then some breeders may decide to breed a double merle sire/dam so they can advertise an all merle litter. Are double merles still able to be registered in breed clubs? Link to comment Share on other sites More sharing options...
juliepoudrier Posted August 1, 2012 Report Share Posted August 1, 2012 I would be hesitant to call it due to breed standards. It is done in some show lines (shelties, danes, and collies I know of) but Koolies and Catahoulas are working breeds. I don’t know if koolies have a standard at all. In all breeds I know of that are merle, doubles are DQ’d from showing. Well people don't breed doubles to show; they create them because then when bred, they will always contribute the merle gene (since they have two copies) to the cross. Merle is dominant. Therefore using a double merle as a breeding dog guarantees more merle puppies. Cross it to any other fancy color and voila extra special candy colors (lilac merle, sable merle, etc.). And buyers do like merle, so the more you can produce, the better. Also, merle is a preferred color in some breeds, like aussies. If you want to increase your chances of having a merle pup that is also suitable for showing, what better way to do that then ensure that all the pups in a litter are merle? Here's what the Catahoula Owners, Breeders, and Research Association says about coat color (it's in their standard): ColorCatahoulas come in an endless variety of coat colors and patterns. All color combinations and patterns can have color points or trim, which may be located on the chest, cheeks, above the eyes, on the legs, underbody or under the tail. The Leopard pattern has a base color with contrasting spots of one or more other colors. Solids have a single coat color. Brindles may have a light or dark base coat color with contrasting stripes. The Patchwork pattern may or may not have one predominant solid color with one or more different size patches of different colors and shades placed randomly on the body. In dogs of equal quality, rich, deep colors are preferable to the lighter colors. However, in evaluating the Catahoula as a true, multi-purpose working dog, coat color is not a primary consideration. No coat color or pattern is preferred. [emphasis added] Serious fault: 70 percent or more white. Disqualification: 90 percent or more white coat color; solid white head; albinism. They say this on their main page (sound familiar?): In addition to these goals, our members are intent on keeping the traits and working abilities of the Catahoula intact as we advance the breed into the future. We do not want the Catahoula to undergo the aesthetic changes that have plagued so many working breeds, only to eliminate their ability to perform the function for which they were originally intended. And a study they have been involved with: Merle Expression and Its Relation to Deafness Within the Catahoula Leopard DogTraci Llanes COBRA was initially founded to include supporting research specifically on the health and genetic issues of the Catahoula Leopard Dog. With this in mind, I would like to inform the members of a research project that many COBRA members have been involved in for the last 2 or more years. I have been collecting and analyzing the genetic makeup of the Catahoula in relation to merle expression and deafness within merle to merle breedings for over 3 years; and have been studying their more general coat color genetics and health issues for 6 years now. The fruit of all this labor has finally been able to be catalogued and is almost ready for proper scientific validation among some of the experts in the field. This has only been made possible with the help of some breeders who have been willing to share their breeding program, health test results, and litter results and who have kept exceptional records for validation of all data supplied. Review Report Unfortunately, you cannot access the report unless you're a COBRA member, which is a shame because there might be some useful information there regarding merle to merle breedings. The COBRA website is here. Note that this isn't the only Catahoula group out there, but in the quick search I did, this one seemed to have the most informative website. J. Link to comment Share on other sites More sharing options...
juliepoudrier Posted August 1, 2012 Report Share Posted August 1, 2012 Oh, and this is good: On the AKC website is a section about the history of the Catahoula, and at the very end of the history is this statement: Catahoulas have been bred by working-oriented breeders since their instincts to work wild hogs and cattle became evident. The ability to handle wild herds is instinct and cannot be taught. A single outcross or crossbreeding so affects the instinct that it eliminates those pups from ever becoming breeding stock. This self governing instinct could easily be lost if bred for pets or show without the trial by fire working aspect being tantamount. Regardless of size, color, or color of eyes, the working instinct is the true acid test of purity in the Catahoula. I don't think a dog fancier wrote that, J. Link to comment Share on other sites More sharing options...
SamS Posted August 1, 2012 Author Report Share Posted August 1, 2012 That sounds like a very interesting study. I just thought of a question: If a blind and/or deaf double merle sire was bred to a non merle dam, would the puppies be more likely to be blind/deaf due to the sire's condition? Link to comment Share on other sites More sharing options...
mtnfrank Posted August 1, 2012 Report Share Posted August 1, 2012 Oh, and this is good: On the AKC website is a section about the history of the Catahoula, and at the very end of the history is this statement: I don't think a dog fancier wrote that, J. That's because they are not an AKC breed (yet). Unlike the Border Collie which is "Recognized worldwide as the premier sheepherding dog, known for its obedience, trainability and natural appearance" It would be very interesting to see that merle study which would present some data to enlighten the merle-deafness debate. It is however a self selecting study, only certain breeders participate, and not yet reviewed scientifically. Still, once the data is compiled and analyzed it would be interesting to know what are the conclusions. Link to comment Share on other sites More sharing options...
Laurelin Posted August 1, 2012 Report Share Posted August 1, 2012 Oh I know show breeders do double merles. I used to have shelties and there are a few top sheltie studs that were double merles, unfortunately. I'm not big into Aussies so havent' seen any big name double merle studs there. Not sure how often that happens. I have just heard people say double merle breeding is a show breeding problem and I disagree. I think it's more than that and don't buy that it's any more ethical if you're breeding for something else. That sounds like a very interesting study. I just thought of a question: If a blind and/or deaf double merle sire was bred to a non merle dam, would the puppies be more likely to be blind/deaf due to the sire's condition? No, the condition will not pass down to offspring. However, in the case of dogs with eye issues from being double merle, you can't tell if the dog does have other inheritable eye problems. Link to comment Share on other sites More sharing options...
juliepoudrier Posted August 2, 2012 Report Share Posted August 2, 2012 I have just heard people say double merle breeding is a show breeding problem and I disagree. I think it's more than that and don't buy that it's any more ethical if you're breeding for something else. I think it's likely a generalization because of the fact that show breeders breed for looks, and merle is a popular color. But I suspect that double merle breedings are done often enough because of the benefit of getting all-merle litters. I would argue that it is a show breeding problem, but not only a show breeding problem. As I said earlier, people create what the market wants. Some do it out of ignorance and some do it full well knowing what they are doing, but choose to take the risk anyway, because the perceived reward is so great. MtnFrank, I was disappointed that the Catahoula folks don't seem to be willing to share the research results with the greater public. There could be some useful information there that could help the owners/breeders of other breeds as well. I would be equally disappointed if the researchers working on border collie issues refused to release their findings to anyone but a specific group of border collie owners. In my opinion, that's not how science should be done. J. Link to comment Share on other sites More sharing options...
SamS Posted August 2, 2012 Author Report Share Posted August 2, 2012 I think that double merles are mainly a backyard breeder problem, but show bred double merles just have a higher profile. Link to comment Share on other sites More sharing options...
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