Breeding Genetics - Page 2

alboe, there is a very high level GSDCA/AKC judge that gives seminars on breeding all over the U.S.

He presents his stick diagrams and advice on line breeding and is much in demand . Yet he has never breed a top dog. He has never placed in front of me or anyone I am acquainted with. And I am considered on a low level.

All this B/S on the genetics is just that. Bull Sh*t.

I have been doing this for 4 decades and my advice is this.

Breed a good bitch to a good dog (whatever your goals are) and see what you get. All this XY sh*t is just that, sh*t, when it comes to the real world.

If the people posting this XY crap really worked, they would now be wealthy from their knowledge.

Rik

Hmnnn, I hear you.

The only sex-linked traits that I know of are recessive detrimetal genes for adverse conditions, such as hemophilia.  Knowing how sex-linked traits are passed makes it easier to remove them from a bloodline.  Just because a person doesn't understand genetics, doesn't mean there's no advantage to be had and they get play outside the rules.  Just as in physics, we're all subject to the laws of gravity, whether we "get it" or not.

Daryl, that is what I was thinking about. If you are breeding a line, you should know these things. It will give you more information about what to avoid. It would be cool to know what's coded on the X chromosome. I know that the canine genome has been mapped so that information should be out there. 

 I was also thinking about figuring out wich traits to look for that are recessive and undesireable because those would be more important to avoid than those that are dominant and undesireable. Especially in breeding your own line.  Rik answered that for a few structural traits and it was very informative. 

Of course hemophilia is an X linked trait.  Another example in animals is calico cats. The coat colors of the calico cat are a result of a random inactivation of an X chromosome. BTW male calico cats are very rare, but do occur with the genotype of XXY. Male calicos are sterile though and can't reproduce. In some dogs, like labs, a phenomenon called epistasis occurs where one allele will hide the effects of another allele which results in varying pigments in the fur. This is because there is an interaction between two genes, each with two alleles. The coat colors in rabbits are determined by four alleles. Multiple alleles increases the variations in coat colors. Genetics is a fascinating branch of Biology and I just finished teaching two units in Genetics to my high school Biology class. There still is so much that we don't know about how traits are inherited. It is much more complex than getting one allele from the mother and one allele from the father for a specific trait.

 This appears to be a good site on canine genetics:  http://www.canine-genetics.com/ .

Hemophilia is technically "sex linked" in that it is expressed in males, coming from the female side.  In a female, the potential contributors are the dam and the paternal grand-dam, as to whether or not she becomes a carrier.

For adverse X-linked traits when the subject is male, you know that you can disregard the diamond plated blocked out producers as having any potential of contributing such a condition.


For adverse X-linked traits when the subject is female, you know that you can disregard these diamond plated blocked out producers as having any potential of contributing such a condition.


If a trait is Y-linked, then these are the only producers of significance.


If a trait is carried through mitochondrial dna, these are the only producers of significance.

There are some ways to predict how temperamental tendencies (not all pups are genetically identical, of course, as puppy pack dynamics will show) will respond to environmental conditions, but you might have to alter some of the ways you currently perceive the components of temperament, and add to that the complex interaction of other trait behaviors that will affect a single component.

1. the interaction of social/environmental factors on the genetic hardwiring as they begin to lay ground for neuroplastic behaviors (mother, litttermates, diet, sensory activity)

2. having a correct understanding of the most irreducible behavior traits.

3. the interaction of other genetically inherent behavior components, what kind of slant each performs on the overall behavior.

This is where it becomes important to have intimate knowledge firsthand of the character and temperaments of the recent few generations.  It's unfortunate that what goes on a dog's record for breeding use are only usualy basic things like size, weight, color, elbow & hip clearances, and perhaps how they performed on a particular day in a sporting event, and in the hands of some "unknown" level of competence. 

What then ultimately grasps our attention, is how well the dog has been promoted, to be both publicly visible and publicly favorable.  And sometimes if we're lucky, someone can testify to some particular character trait or two passed by the said producer, and sometimes that testimony will conflict with someone else's personal experience.

 That's good information to have. It would be interesting to survey breeders who have maintained a line over a few generations and ask them about what they have noticed. What's passed on easily and What can and can't be trained away from easily.      


If there is information out there to guide you breeding, we should use it.