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| | #361 |
| Donating Member Join Date: Feb 2008 Location: Mississippi
Posts: 2,564
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| Welcome Guest! | |
| | #362 |
| Thor's Human Donating Member | Woogie Man, here is where I see the debate at this point: You brought up factual information regarding pie bald coloring indicating that it is associated with deafness and blindness in other breeds. You then asked if there was reason to believe that this could be true in yorkies as well. You also asked some rather provocative value questions as to whether the risk was worth taking. After that, you answered your own questions, saying that it was likely that pie bald yorkies would have the same problems, and that it was wrong to take that risk ("russian roulette"). From what I've seen, one person(?) said that they've observed five generations of parties and seen no issues. This is reasonable, though not iron clad, evidence. Other people have said that they would observe breeding results and only beed healthy lines. There are other breeds of dogs where you have to be careful you don't over-select for a particular physical trait, and in fact, have to breed every other generation back with a dog that doesn't display the desired trait. As for whether the risk is worth it, well, since it's a value judgment, people are going to come up with different answers. I agree that not all responses to you have been particularly polite or well informed, but many of them have been, and since you do seem to have some bias, people are going to react to that. As always, just my opinion. |
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| | #363 |
| Donating YT 1000 Club Member Join Date: Jan 2006 Location: In my house :)
Posts: 5,219
| I hope I didn't say anything that upset you. I have Biewers and I am certainly not in denial as to their breeding future...I am going into this with my eyes wide open. I have learned a great deal from reading this thread and from the links you posted. The only point I wanted to make is that there are health issues, and serious ones, or the potential for them, in all breeds. |
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| | #364 | |
| Donating YT 12K Club Member Join Date: Jan 2006 Location: Council Bluffs Iowa
Posts: 12,552
| Quote:
I said right from the beginning that we would watch for that and change our breeding practices if that happened. the only other alternative is to not breed at all. No one, including you, seemed to be satisfied with that answer. You all kept harping on it. We are not ignorant, we know there are risks as there are with any breeding program or anytime some one ventures into unknown territory. But that has not stopped people in the past, and it won't stop us. all we can do is tell you that we plan to do it responsibly, only time will tell the outcome. we've been told we are in it for the money, that we are ruining the breed, that we are going to produce deaf dogs, that responsible breeders breed to the standards set by they YTCA, like the YTCA created them. We've heard it all and we are not going to stop. so you can ll quit harping. As for the facts. You have yet to produce any facts of any parti colored yorkies producing deaf puppies. True it has happened in some other breeds, but equally true that it has not happened in all other breeds. We cannot prove something that never happened. All pioneers go through this same sort of ridcule, yet they proved that the earth was not flat, that life did exst on the other side of the mountains etc. but they could not have proved it if they had litened to all the nay sayers. I bet way back when, they were told that they could not possibly turn a 100 pound wolf into a 5 pound, long haired, two toned dog, had those people listened, we would all have pet wolves. parti colored yorkshire Terriers are here to stay. Get used to it. | |
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| | #365 | |
| Donating Member Join Date: Feb 2008 Location: Mississippi
Posts: 2,564
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| | #366 | |
| Donating Member Join Date: Feb 2008 Location: Mississippi
Posts: 2,564
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| | #367 | |
| Donating Member Join Date: Feb 2008 Location: Mississippi
Posts: 2,564
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| | #368 |
| Donating Senior Yorkie Talker Join Date: Aug 2006 Location: Virginia
Posts: 923
| From what I've read, dogs that go deaf as a result of the extreme piebald gene, normally loose their hearing within the first few weeks of life, it's not something that may happen 5 or 10 years down the road with a dog (at least where the parti gene is concerned). "Deafness associated with piebald coloring is inherited in some breeds, but the presence of the gene by itself is not sufficient to cause deafness. For example, all Dalmatians have two copies of the extreme piebald gene (homozygous), but not all of them are deaf – there appear to be other genes involved as well. However, it is important to eliminate other causes for deafness before coming to a conclusion that your animal is deaf due to the extreme piebald gene. Deafness in Samoyeds is not common (extreme white), but may be attributed to any of the following, or a combination thereof; Congenital (present at birth) - Genetic (hereditary) Congenital (present at birth) - Acquired (for example, dam exposed to toxic drug) Otitis (inflammation) through bacteria or fungal infections in Inner or Outer Ear Injury by accident or foreign body invasion Old age (Presbycusis) Drug Toxicity including General Anaesthesia Noise Trauma However, not all breeds with these genes (parti) have been reported to be affected. The deafness, which usually develops in the first few weeks after birth while the ear canal is still closed, usually results from the degeneration of part of the blood supply to the cochlea (the stria vascularis). The nerve cells of the cochlea subsequently die and permanent deafness results. The cause of the vascular degeneration is not known, but appears to be associated with the absence of pigment producing cells (melanocytes) in the blood vessels. All of the function of these cells are not known, but one role is to maintain high potassium concentrations in the fluid (endolymph) surrounding the hair cells of the cochlea; these pigment cells are critical for survival of the stria. Deafness in the Doberman, which is also accompanied by vestibular (balance) disturbance, results from a different mechanism, where hair cell death is not the result of degeneration of the stria but is instead the primary cause. Deafness may also occur later in life in dogs from other causes such as toxicities, infections, or injuries, or due to aging (presbycusis); these forms of deafness almost never have a genetic cause in animals and thus do not present a concern in breeding decisions." Piebald or Extreme Piebald Gene – Deafness — Samoyed Club of America Education and Research Foundation (SCARF) Genetics of Deafness in Dogs
__________________ Sue White www.pinehavenyorkies.com Colorful Yorkshire Terrier Club www.colorfulyorkie.com |
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| | #369 | |
| Donating YT 12K Club Member Join Date: Jan 2006 Location: Council Bluffs Iowa
Posts: 12,552
| Quote:
Looks like while the rest of us were on here hashing over the possibility, you went and did your homework.. good job, thank you for the information. | |
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| | #370 |
| YT 3000 Club Member Join Date: Jul 2007 Location: HOT, HOT, HOT AZ
Posts: 3,150
| Deafness Somewhat rare. This condition is possibly linked to Papillons which carry a Piebald gene. The genes affect the amount and distribution of white areas on the body. Deafness can be described as (1) congenital or late onset, (2) hereditary or acquired, and (3) conductive or sensor neural. Congenital deafness is affected by a Piebald gene. That makes the mismark or almost all white Papillon being a suspect of higher incidence because it is an extension of the piebald gene. The mechanism of inheritance is not known, and not only mismarks have been affected by deafness. Unilateral (one ear) and bilateral (both ears) deafness has been diagnosed in Papillons. Not enough Papillons are routinely tested to compile reliable statistics about deafness. Behavioral deafness detection with young puppies in the home is difficult, as the deaf young cue off the behavior of their littermates. Often deafness is not noticed until the puppies are separated from their littermates. A puppy that does not awaken in response to a loud noise is almost certainly bilaterally deaf, but the unilaterally deaf cannot be detected with any reliability. As a consequence, behavioral hearing assessment of animals in the clinic or home is of limited reliability. If deafness is suspected a "BAER" Brainstem Auditory Evoked Response (electro diagnostic) test should be given by a qualified veterinarian. Thought this might interest all of you parti breeders. Maybe all puppies should be BAEr tested as unilateral deafness is hard to detect.
__________________ BUYCOTT ARIZONA![]() ![]() |
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| | #371 | |
| Donating YT 12K Club Member Join Date: Jan 2006 Location: Council Bluffs Iowa
Posts: 12,552
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| | #372 | |
| I ♥ Joey & Ralphie! Donating Member | Quote:
From what I've read, Congenital (present at birth) - Genetic (hereditary) means that the condition is present at birth and it's hereditary, but it does not mean the condition always displays itself at birth. There are two types, piebald, and extreme piebald, and only in the extreme piebald will the condition be displayed at birth.
__________________ Nancy Joey Proud members of the CrAzYcLuB and YAP! ** Just Say No to Puppymills – Join YAP! Yorkshire Terrier Club of America – Breeder Referrals ![]() | |
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| | #373 |
| YT 3000 Club Member Join Date: Jul 2007 Location: HOT, HOT, HOT AZ
Posts: 3,150
| Genetics of Deafness in Dogs -- George M. Strain, PhD Inherited deafness can be caused by a gene defect that is autosomal dominant, recessive, sex-linked, or may involve multiple genes . It is usually impossible to determine the cause of congenital deafness unless a clear problem has been observed in the breed or carefully planned breedings are performed. In this article I will discuss what is currently known about the genetics of deafness in dogs so that breeders can make the best informed decisions possible when attempting to reduce or eliminate deafness. Congenital deafness has been reported for approximately 60 breeds, with the list growing at a regular rate ; it can potentially appear in any breed. The deafness has often been long-established in a breed but kept hidden from outsiders to protect reputations. The disorder is usually associated with pigmentation patterns, where increasing amounts of white in the hair coat increase the likelihood of deafness. Two pigmentation genes in particular are often associated with deafness in dogs: the merle gene ( Collie, Shetland Sheepdog, Dappled Dachshund, Harlequin Great Dane, American Foxhound, Old English Sheepdog, and Norwegian Dunkerhound among others) and the piebald gene (Bull Terrier, Samoyed, Greyhound, Great Pyrenees, Sealyham Terrier, Beagle, Bulldog, Dalmatian, English Setter). Not all breeds with these genes have been reported to be affected. The deafness, which usually develops in the first few weeks after birth while the ear canal is still closed, usually results from the degeneration of part of the blood supply to the cochlea (the stria vascularis). The nerve cells of the cochlea subsequently die and permanent deafness results. The cause of the vascular degeneration is not known, but appears to be associated with the absence of pigment producing cells (melanocytes) in the blood vessels. The function of these cells is not known but appears to be critical for survival of the stria. Deafness in the Doberman, which is accompanied by vestibular (balance) disturbance, results from other mechanisms. Deafness may also occur later in life from causes such as toxicities, infections, or injuries, or due to aging (presbycusis); these forms of deafness almost never have a genetic cause in animals and thus do not present a concern in breeding decisions. The incidence of congenital deafness in different breeds is seldom known because of the limited number of studies. In the Dalmatian, where the incidence is highest, 8% of all dogs are bilaterally deaf and 22% are unilaterally deaf. In the English Setter, Australian Cattle Dog, and Bull Terrier, where fewer numbers of dogs have been hearing tested, the incidence appears to be about ½ of that of Dalmatians. Unilateral or bilateral deafness is found in 75% of all white Norwegian Dunkerhounds, but the incidence in normal-color dogs is unknown. Other breeds with a high incidence are the Catahoula and Australian Shepherd. The incidence of all types of deafness in the general dog population is low, reported to be 2.56 to 6.5 cases per 10,000 dogs seen at veterinary school teaching hospitals. Recognition of affected cases is often difficult, because unilaterally deaf dogs appear to hear normally unless a special test (the brainstem auditory evoked response, BAER) is performed; facilities to perform the BAER are usually only available at veterinary schools. It should be noted that a unilaterally deaf dog can be as great a genetic risk for transmission of deafness to its offspring as is a bilaterally deaf dog. The method of genetic transmission of deafness in dogs is usually not known. There are no recognized forms of sex-linked deafness in dogs, although this does occur in humans. The disorder has been reported to have an autosomal recessive mechanism in the Rottweiler, Bull Terrier, and Pointer, but this suggestion is suspect because the reports were before the availability of BAER testing and the ability to detect unilaterally deaf dogs. References usually state that deafness transmission in most other breeds is autosomal dominant, but there is reason to believe that this is not true, as will be discussed below. Pigment-associated inherited deafness is not restricted to dogs. Deafness in blue-eyed white cats is common and is known to be passed on as an autosomal dominant defect. Blue eyes, resulting from an absence of pigment in the iris, is common with pigment-associated deafness but is not, in and of itself, an indication of deafness or the presence of a deafness gene. Waardenburg's syndrome in humans presents with deafness, a stripe of white in the hair and beard, blue or different colored eyes (even in blacks and asians), no pigment behind the retina, and minor structural deformities around the nose and eyes. This is an autosomal dominant disorder with incomplete penetrance, which means that individuals that inherit the disorder may not show all components of the syndrome - i.e., they may not be deaf. In simple Mendelian genetics, each dog carries two copies of each gene, one from each parent. The possible outcomes of breedings can be demonstrated with tables showing the genotype of both parents and the possible combinations in their offspring. If deafness is carried as a simple autosomal recessive gene (d), the breeding of two hearing carriers (Dd) (Table 1) will result, on average, in 25% affected dogs (dd), 50% hearing carriers (Dd), and 25% free of the defect (DD). The breeding of a carrier to a dog free of the defect (Table 2) will result in no affected dogs but 50% carriers and 50% free. The breeding of an affected dog to a carrier (Table 3) will result in 50% affected, 50% carriers, and no free. Finally, the breeding of an affected dog to a dog free of the defect (Table 4) will result in 100% carriers and no affected or free. If instead deafness is carried as a simple autosomal dominant gene (D), the breeding of an affected dog (Dd) to a free dog (dd) (Table 3) would result on average in 50% affected and 50% free. Dogs with the genotype DD would be unlikely to occur unless two deaf dogs had been bred. All of the above assumes that incomplete penetrance is not acting. If more than one gene (recessive and/or dominant) is involved in producing the deafness, the possible combinations become much more complicated. It is estimated for humans that there are 10-15 different autosomal recessive deafness genes, so that children of two deaf parents can be unaffected but carry both genes. If deafness in dogs results from more than one recessive gene, the possible outcomes of breedings are more numerous and determination of the mechanisms of transmission will be difficult. As stated above, deafness is often associated with the merle (dapple) gene, which produces a mingled or patchwork combination of dark and light areas. This gene (M) is dominant so that affected dogs (Mm) show the pattern, which is desirable in many breeds. However, when two dogs with merle are bred, 25% will end up with the MM genotype (i.e., Table 1). These dogs have a solid white coat and blue irises, are often deaf and/or blind, and are sterile. Breeders of these dogs know not to breed merle to merle. In this case the deafness is neither dominant nor recessive, but is linked to a dominant gene that disrupts pigmentation and secondarily produces deaf dogs. Genetic transmission of deafness in dogs with the piebald (sp) and extreme piebald (sw) pigment genes, such as the Dalmatian, is less clear. These genes affect the amount and distribution of white areas on the body. Deafness in Dalmatians does not appear to be dominant since deaf puppies result from hearing parents. It does not appear to be a simple recessive disorder: we have bred pairs of deaf Dalmatians and obtained bilaterally hearing and unilaterally hearing puppies, when all should have been deaf if it was recessive. These findings might be explained by a multi-gene cause, the presence of two different autosomal recessive deafness genes, or a syndrome with incomplete penetrance. Further studies (in progress) will be required to determine the mechanisms. So what should breeders do when deafness crops up? The most conservative approach would be to not breed the affected animal and not repeat the breeding that produced deafness. It is frequently recommended (i.e. Dalmatian Club of America) that bilaterally deaf puppies should be euthanatized, since they make poor pets, are prone to biting, frequently die from misadventure (cars), and require excessive care. There is considerable controversy on this point (see The Deaf Dogs Web Page), and there is no question that many people have successfully raised deaf dogs. For every horror story of a problem deaf dog there seems to be a story of one that was successfully raised. Unfortunately, there is no way to predict how a deaf puppy will turn out. Unilaterally deaf dogs can make good pets but should not be bred. When deafness is uncommon in a breed, affected dogs should not be bred, but this does not mean that all related dogs are a risk and must be retired from breeding. An understanding of simple autosomal recessive and dominant patterns, as explained above, can allow the breeder to make informed decisions and likely avoid future deaf animals without sacrificing a breeding line that has been shaped over many years. However, extreme caution must be used when line breeding of dogs related to deaf dogs, whether the deafness is unilateral or bilateral. To make these decisions in an informed manner for breeds with known deafness, it is important that advantage be taken of hearing testing facilities at veterinary schools. Unilaterally deaf dogs cannot be detected by other means, and these dogs will pass on their deafness genes. Not to keep kicking a live horse, but this last sentence is very informative also.
__________________ BUYCOTT ARIZONA![]() ![]() |
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| | #374 |
| Thor's Human Donating Member | Now we're getting somewhere! ![]() JeanieK, can I ask how it is that you would like to breed partis, but have not produced any yet? Do you breed standard yorkies and you're hoping to see a parti eventually? |
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| | #375 |
| Donating Member Join Date: Feb 2008 Location: Mississippi
Posts: 2,564
| It is good to see this info posted. If you read enough of these type pages, you'll find the info to be consistent and validated by science. Though not alarmist, these sites do urge caution when breeding piebalds. The links posted earlier say much the same. Here's something from a Chihuahua site...."Spotting/Piebald Pattern Gene is a recessive, complete pigment reducing pattern gene, which removes ALL pigment to white in random unpredictable areas affected by the gene, it removes all colors to those areas affected, thus no color present, extreme whites by definition with blue eyes are partial albinos, therefore by default partial albinos must be considered a form of albinism. Blue eyes have been linked to the piebald gene, spotting gene has been linked to microphthalmia. See the prior link for spotting gene specific microphthalmia. All litter mates and parents of a blue eyed whelp pup must be considered a recessive carrier of the recessive blue eye gene. Piebald and or spotted on whites and excessive whites are homozygous forms of the piebald(SP/SW) gene. It is a recessive gene, therefore it can skip generations, and at this time can not be DNA'ed for its presence, but it is just around the corner, see our health testing page for more info. It is still uncertain if recessive carriers can or are effected by the gene linked disorders. Piebald/spotting gene effects a large majority of the canine breeds, and it is causing problems within many breeds. Some breeds more than others. It has be scientifically proven that the more patches of color the less likely the chance for disorders. Proving once more color is a healthier choice for the breeder and the dog. See a medical article on the spotting gene. Breeds/ Facts about the risk of the spotting gene in many canine breeders. Dalmatians, Bull Terriers, Great Danes, Bulldogs and many other breeds openly discuss their concerns over too much white and/or the presence of the piebald gene, below we will share just some breed clubs with open concerns. Samoyed Club : Bichon Frise Club : Boxer Club : Biewer Club there are many more, we just want to show you how piebald, spotting gene effects health and how some breed clubs are coping with the spotting gene LSU article, breeds most affected by deafness, MITF news , breeds with congenital deafness, Dr. Strain misquoted, There are many more research sites to study, but we wanted to give a starting point to find some facts we referred too".....Here's the link...Patterns |
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