Carriers

[**Super_Dogs**]

I am in the process of DNA testing a couple of my dogs so it has got me thinking about breeding with carriers.

Would you use a carrier for breeding?

I can understand why some people say to only breed with clear, but being that a carrier does not exhibit disease symptoms as long as the carrier is breed with a clear there is not risk of any puppies being affected. So isn't this OK?

With the increasing number of breeders DNA testing, for diseases not required by ANKC, aren’t we going to see more and more carriers? So it begs the question, is the aim of DNA testing to remove all carriers from the breed? Or is it to ensure there are no affected dogs? If we try to eliminate the disease all together won't this significant reduce the lines available?

Look forward to your thoughts.

Edited October 31, 2011 by buddy1

[Sandra777]

It would depend a lot on the disease, it's prevelence in the breed, the quality of the dog/bitch concerned and the importance of it's bloodline to the breed and to yourself.

Yes I have contemplated breeding from a carrier - she was the only bitch produced by a dog I bred which died before either of his 2 litters were born. I knew her mother was a carrier at the time of the mating but the dog was clear and of the 5 pups 2 were carriers (pick dog and only bitch of course!) and 3 clear.

I ended up not breeding from this bitch as we moved countries and didn't bring her with us, but had we stayed in NZ I would have.

[underfoot]

I guess it comes down to the question......Are we breeding to improve the breed? Personally myself I try to avoid using any dog with any known genetic fault that can be passed on through their offspring. But that is my choice. The last thing I would want to see is a dog in a pet home having problems later in life due to a fault I could have avoided.

Cheers

[**Super_Dogs**]

I guess it comes down to the question......Are we breeding to improve the breed? Personally myself I try to avoid using any dog with any known genetic fault that can be passed on through their offspring. But that is my choice. The last thing I would want to see is a dog in a pet home having problems later in life due to a fault I could have avoided.

Cheers

I too would not want to breed if there was any changes of the puppies having problems.

However, is a carrier considered a genetic fault considering they do not have the disease?

I read something that said that DNA tests were never meant to be used to eliminate carriers of autosomal recessive conditons. They were meant to assist in breeding dogs that are not affected and therefore enable carriers to be safely used in a breeding program.

FYI - for my breed there disease tested for are not csonider miderate and low severity.

Edited November 1, 2011 by buddy1

[Sayly]

Why throw the baby out with the bath water? In some breeds, breeding from only clears would drastically reduce the gene pool. Why reduce the quality of the breed, and risk other diseases which we can't yet test for, by breeding only from clears, when breeding from a carrier to a clear is never going to produce affected animals.

[WreckitWhippet]

Yep, no worries at all in using one. Providing the status of the dog and bitch is known. Everytime we chuck out carriers, we narrow the gene pool. A carrier is just that and there's no harm in breeding from one. Why rule out an otherwise excellent specimen.

[dancinbcs]

As one of the instigators of the development of two genetic tests for my breed, I can tell you

DNA TESTS WERE NEVER INTENDED TO ELIMINATE CARRIERS FROM THE GENE POOL.

The whole point of having genetic tests is to keep as many dogs as possible in the gene pool while safely breeding no affected puppies. Once a DNA test for a recessive condition is developed it means that condition is no longer a problem and no more affected puppies need to be born. Every animal, including humans and all dogs, carry several defective genes. The ones with a DNA test are just the few that we know about. Eliminating carriers of one condition by DNA testing just leads to an increase in the concentration of other faulty genes that there are no tests for. Short sighted and stupid.

We are only in the very early stages of DNA testing for dogs and no doubt lots of other tests will be available over the coming decades. It may end up that each breed is tested for 6-10 different genes. We already have 3 in my breed. If we eliminate the carriers of all those conditions, how many dogs do you think will be left to breed from? The most important points of breeding dogs are still temperament, sound construction and breed type. Using DNA testing to still produce quality dogs while avoiding disease is smart. Just breeding all DNA clear for disease dogs is dumb and will spell the end of dogs altogether.

[**Super_Dogs**]

DNA TESTS WERE NEVER INTENDED TO ELIMINATE CARRIERS FROM THE GENE POOL.

The whole point of having genetic tests is to keep as many dogs as possible in the gene pool while safely breeding no affected puppies.

This makes perfect sense!!! This was my understanding (it did not make sense to me to elimiate all carriers) but DNA testing is new to me, so thanks so much for the clarification.

Thank you everyone for your replies!!

[Leema]

Why throw the baby out with the bath water? In some breeds, breeding from only clears would drastically reduce the gene pool. Why reduce the quality of the breed, and risk other diseases which we can't yet test for, by breeding only from clears, when breeding from a carrier to a clear is never going to produce affected animals.

Agree.

[Sandra777]

I guess it comes down to the question......Are we breeding to improve the breed? Personally myself I try to avoid using any dog with any known genetic fault that can be passed on through their offspring. But that is my choice. The last thing I would want to see is a dog in a pet home having problems later in life due to a fault I could have avoided.

Cheers

A carrier of a recessive mated to a clear can never produce a puppy with problem "later in life" or any other time.

Before you make blanket statements you need to consider the nature of recessive genes and that different diseases have different modes of inheritance.

You can improve the breed by breeding from superior dogs with a known genetic fault far quicker than breeding from mediocre dogs with no known genetic faults but quite possibly still carrying some genetic condition which no one has discovered a test for (yet)

[underfoot]

I guess it comes down to the question......Are we breeding to improve the breed? Personally myself I try to avoid using any dog with any known genetic fault that can be passed on through their offspring. But that is my choice. The last thing I would want to see is a dog in a pet home having problems later in life due to a fault I could have avoided.

Cheers

A carrier of a recessive mated to a clear can never produce a puppy with problem "later in life" or any other time.

Before you make blanket statements you need to consider the nature of recessive genes and that different diseases have different modes of inheritance.

You can improve the breed by breeding from superior dogs with a known genetic fault far quicker than breeding from mediocre dogs with no known genetic faults but quite possibly still carrying some genetic condition which no one has discovered a test for (yet)

This was not a blanket statement. It was my opinion ONLY. I am in a breed that does not carry many genetic issues so for me it is not an issue. I do understand the need for other breeds to consider using dogs with genetic issues hence I said I try to avoid faults that are passed on though offspring that may affect them later in life.

[Lowenhart]

Yes I'd use a DNA confirmed carrier in breeding if it was a quality animal with a good pedigree.

Unfortunately my breed has no DNA testing but I have chosen to incorporate a line that is decended from an affected dog of a recessive disease. The quality of the animals, the temperament, the other health aspects are top notch. The line has a high rate of health testing and I'd rather have that then a supposedly clear dog who hasn't had generations of testing of siblings etc.

[sandgrubber]

All else equal, I'd prefer a clear to a carrier. It's a blessing to know all pups are going to be clear, and to be able to declare "clear by inheritance" with no more than a paternity test. I wouldn't rule out using a carrier, but the dog would have to be extra special to justify using a carrier for a serious disease.

I'm more relaxed about EIC (exercise induced collapse . . . a recessive trait that's fairly common in Labradors) than PRA . . . as many affected dogs go through their entire lives without exhibiting EIC and very very few of the pups I've bred end out in the sort of heavy duty hunting / field competition circumstances where EIC can become a problem.

[angelsun]

I have used and will use again, a carrier...it's only a carrier, not affected (doesn't matter the disease) As long as testing is around, and I can test offspring, and make decisions and go from there...it's a non issue for me really.

In saying this, I would not do a carrier/carrier mating, but only carrier/clear.

[**Super_Dogs**]

All else equal, I'd prefer a clear to a carrier. It's a blessing to know all pups are going to be clear, and to be able to declare "clear by inheritance" with no more than a paternity test. I wouldn't rule out using a carrier, but the dog would have to be extra special to justify using a carrier for a serious disease.

I'm more relaxed about EIC (exercise induced collapse . . . a recessive trait that's fairly common in Labradors) than PRA . . . as many affected dogs go through their entire lives without exhibiting EIC and very very few of the pups I've bred end out in the sort of heavy duty hunting / field competition circumstances where EIC can become a problem.

I looked at some studies on EIC with Labs and I was really surprised how such a small ammount within the samples where clear.

[EISHUND]

Yes, I have just had a litter with a confirmed carrier of MDR1 (IVM). This is not a disease, it is a gene mutation. She was mated to a male who has tested clear. I too am a believer that testing is to ensure no affected dogs are produced without limiting the genepool.

I was the first in Australia to begin testing for this within our breed (White Shepherd, prior to recognition & my importation of White Swiss Shepherd Dogs, and have continued to test), and WOW was i absolutely ridiculed by some in the community, citing it as a waste of money & claims that I was trying to make myself look better by testing! OMG, I was of the opinion, that ANY available test for a condition within the breed was a great tool to take advantage of, and that is my reason for doing the testing, didn't expect to be outcast & called 'elistist' because of what I felt were good breeding ethics.

My biggest issue is with the idiots out there breeding from known carriers & mating them to untested dogs, then on-selling their pups to buyers & not informing them, who then go on to breed again, untested, to untested dogs! Grrr... That type of irresponsibility irks me & shows a complete disregard of breeding ethics if you ask me! Mind you, this is within the unregistered genepool. Thankfully ALL of the ANKC registered dogs used in breeding programs around Australia have been tested & their status known, and I hope it stays that way. =)

[miniluv]

Yes I have used Carriers in the past and will use again in the future. These Carriers are only ever mated to clears and all the litter is then DNA tested before they go off to their new homes. If used sensibly and correctly there should not be a problem.

[*Lolapalooza*]

I was the first person in Australia to DNA test my Bernese Mountain Dogs for Degenerative Myelopathy, as far as I am aware only 2 other breeders in the country have done this also.

My foundation bitch is Carrier, she already had a litter prior to this testing being available and thankfully the sire was Clear

Even if Carrier is bred to Carrier, the offspring can be clear, carrier or at risk. Any offspring who then have an 'At Risk' result have only a 10% chance of developing the disorder.

Hopefully more breeders will be utilising the testing soon to get a clearer picture of the breed status.

[becks]

Yes I have used Carriers in the past and will use again in the future. These Carriers are only ever mated to clears and all the litter is then DNA tested before they go off to their new homes. If used sensibly and correctly there should not be a problem.

Why are you testing the whole litter? i presume most of the litter would be going as pets and so if they are carrier or clear isn't important?

[miniluv]

All Miniature Bull Terrier breeders test their litters to obtain there PLL status unless clear by parentage. For me it could be a very even litter and i'd like to keep a clear male for my breeding program. It's very very rare however there has been confirmed cases of carriers sub-luxating If i have the PLL status available I can then give this information to the puppy buyers.