genetics

[winniecnm]

Hello, winnie again! I was wondering if anyone knew of books about genetics that were focused on dogs or even rotties. Or even if anyone knew of a website that would answer questions about dominant traits and all that stuff. I took this same class for humans now I want to lean more about our four legged friends. For example, if you crossed a dog that is narrow in the chest and east and west with the front feet with a normal bitch, would you wind up with 75% normal and 25% east/west? Those are the kinds of answers I am looking for. http://www.rottweiler.net/rottie/smile.gif

[FredAl]

I don't think you will find exact, proven answers to the kind of questions you pose.

Breeding is an art, not an exact science. One example that dog breeders have to contend with is the case of chromosomal inheritance. I'm sure you'll understand this from your studies of human genetics. Dogs have 39 chromosome pairs; humans have 23. During reduction division, the chromosome pairs separate, one of each pair going into one or the other side of the nucleus. The nucleus then divides,leaving each half with 39 chromosomes, one of each kind.

The key to this is that it is pure chance how the chromosomes line up before cell division.

A method to illustrate this:

Take two sets of poker chips or paper -- for example, red and white poker chips. Number each set 1 through 39. Mix them together in a bowl and then draw them out one at a time. Arrange them into two piles, 1 through 39.

When you have finished, you will have two piles numbering 39 each. But they will not be all the same color in either pile. (Well, they could, but it is exrtremely unlikely.)

You can let red represent the sire and white the dam, and the two piles will represent the two halves of the germ cell in reduction division.

This can be enlarged further by setting up another group with blue and yellow chips representing your bitch (be sure to discard one pile, which would represent the polar body that is discarded in reduction division of the female). Now add the male chromosomes, giving you 78 chromosomes, or 39 pairs.

Now set up two equal piles. Each pile represents just one of the possible chromosome combinations your puppies might inherit. How many chips represent each of the grandparents? If you keep selecting different combinations, you will see that it is possible that one of the grandparents might not be represented at all.

Now put all the chips back and do it again. No matter what you got the first time, it will be different the second time. Even if the colors are the same, you would find that the different chromosome numbers are different.

An exception to this is when a mutation occurs.

[winniecnm]

I just found a bunch of pages on the net. There is one at http://www.workingdogs.com/genetics.htm that might be of some interest. Also I found a group at MSU that is working on canine genetics http://www.msu.edu/~k9genome and http://www.workingdogweb.com/wdhealth.htm There are a ton of websites that are really neat - just one more http://bowlingsite.mcf.com/Genetics/ColorGen.html The last one deals with coat color. I guess that from the research I have done that they are close to mapping the entire canine DNA. What I did was use MSN search and typed in genetics, canine. They are also offering online courses in canine genetics I am considering taking. http://www.rottweiler.net/rottie/smile.gif

[Orville Story]

This is an excellent question. But this is the delima. Why is the dog going east west in the front? Why does the other dog appear to be straight? How close in overall structure are the two?

If I breed an extremely tall rottie that is straight in front to an extremely short rottie that is straight in front would the offspring be straight?

There is just too many variables to come up with a precentage verse breeding fruit flies.

[winniecnm]

From what I read on the one website. there are DNA tests availible to see if your dog is a either free of certain traits, a carrier for certain traits and determine if those certain traits are recessive or dominant. For example, the one lab is offering Linked Marker tests to screen for Retinal Dysplasia is Shih Tzu dogs. I looked through their website and they don't currently offer tests for CHD in rotties but they are looking for people to volunteer their dog's DNA sample (taken from the cheek) from families of two or more puppies affected with the disease. They still need about 50 more samples before they get their target of 100 specimens. If you kbow of anyone who would like to donate, email me and I'll give you the website. I was'nt sure if I could give it out here because they are a business. It would be nice to eventually have all breeding stock tested so breeders would know down to a percentage the chances of producing affected puppies. While we are on the subject, how far do you think genetics should go? In the next five years it may become possible to map out all the flaws and faults in our breed and determine who was clear and who was affected. They have coat color predictions availible now for several breeds, what is next? If they have managed to map out the four alleles that determine coat color, who knows what else we are capable of?

[FredAl]

winniecnm,

Your original post gave an example concerning breeding to correct structural faults, asking exact percentages on the end result.

From the available technology at this time, the question you posed is still impossible to answer with scientifically backed answers.

Science has just recently karyotyped dogs and are still trying to map out the canine genome. They still don't know the number of genes that exist in dogs, or where on the various chromosomes specific genes are located.

This is why I cited the example with the colored poker chips. Dog breeding is still considered an art. Hopefully, science will give the breeders the tools and information so that they can start breeding perfect dogs with the desired temperament, health and conformation.

I wish you good luck in your studies, and hope that you will be part of the advances made in this scientific undertaking.

[winniecnm]

Just to pick your brains a little bit more-
One of the sites I was recently on seriously questions the purity of AKC bred dogs. I'd have to go back a little to find the link. What steps do you guys recommend the registery take to ensure that people aren't being fraudulent with their claims of purity in their lines? Should we in the future force breeders to verify proper parentage and lineage through DNA testing? Should we place limited registration on all puppies until they are proven to be worthy of breeding and force the owners to have both breeding partners pass a suitability test? These things seem to be common sense. Before I bought my rotties, I asked to see the parents and I thought of what the standard described. I looked also at the pedigree and liked the fact that many of the parents were ADRK. It seems that the ADRK has more quality control measures than the AKC. And don't forget the "purebreed" red rottweilers in the local newspaper - don't want to miss out on them! http://www.rottweiler.net/rottie/biggrin.gif Let me know what you think!

[FredAl]

Brain-picking replies:

One of the sites I was recently on seriously questions the purity of AKC bred dogs. What steps do you guys recommend the registery take to ensure that people aren't being fraudulent with their claims of purity in their lines?

AKC is only a breed registry, and relies solely on the integrity of the papers submitted. The system is wide open to fraud and abuse (one claim is that there are more than 10,000 fraudulent registrations). The policing and monitoring of breeders should rest on the breed clubs, i.e., ARC, USRC, ADRK. ADRK's registration regulations, although not totally fool-proof, lessens fraudulent claims and registrations by limiting breedings of dogs and kennels, and through Breed Wardens who check and tattoo puppies registered with the club. I think DNA-testing should be added to the system just for verification. By the way, DNA-testing is now being implemented by the AKC.

Should we in the future force breeders to verify proper parentage and lineage through DNA testing?

DNA testing is important in any breeding program to assure the accuracy of a dog's genetic make-up. Breed clubs should include this as part of their ethical and responsible breeding guidelines. This way, if a breeding is questionable, there is a way to verify its integrity.

Should we place limited registration on all puppies until they are proven to be worthy of breeding and force the owners to have both breeding partners pass a suitability test?

Not all puppies are acquired for breeding purposes. To 'force' owners into doing anything is "UN-democratic" and will go against some of their rights and freedoms.

I guess the proper attitude to take is "Trust, but verify." -- Ronald Reagan (quote from speech on Arms Reduction Treaty)

[winniecnm]

[quote]Originally posted by FredAl:
[b]Brain-picking replies:
Not all puppies are acquired for breeding purposes. To 'force' owners into doing anything is "UN-democratic" and will go against some of their rights and freedoms.

FredAl- I didn't mean it that way, I guess that it would be unfair to demand limited registrations be given to all puppies, but I meant that an additional evaulation should be in place to allow people to breed a their stock, like the gekort title in ADRK. This would put a crimp in BYB breeder's style, since their main attraction is that "pureblooded AKC" found so tactfully put in their newspaper advertisement. I thought I was the only one who stays up this late! http://www.rottweiler.net/rottie/wink.gif

[FredAl]

I've always been in favor of breed suitability tests and evaluations (read my posts about ZtP's and BST's).

BYB's will always find ways to sell their puppies. To put a 'crimp' on them, we need to educate the buying public -- the new rott enthusiasts. This way, they will know to keep away from these BYB's, pet store pups, and puppy mills.

Going back to your original topic, genetics and DNA testing can play an important role in keeping the integrity of bloodlines; and put another crimper on the BYB's who may try to claim a certain pedigree on their puppies.