Question for Genetics - Page 1

Hi dear all genetics people, I have a query. If I have a litter and I know uptill 5 generations of that pedigree for that litter, and I know the qualities of each Sire and Dam in each generation then how do I come to the conclusion what traits each generation would carry? Is ita sum simple total of traits of mother and father? How do you come to a theoretical conclusion of hwat the descendants traits would be? regards

I don't think you'll ever be able to find a theoretical equation that will be able to predict the traits of a litter. Knowing the pedigree can give valuable information in the sense that some lines carry "social aggression" or "high prey drive", or some females tend to produce large progeny, etc. However, to derive a predictive mathematical equation with any semblence of accuracy? Well's that's a tall order indeed! If only it were that easy!

if there is someone out there who can help on this would really appreciate.

regards

if there is someone out there who can help on this would really appreciate.

regards

Hi Vikram,

In my breeding program, I try to know the traits of as many ancestors, siblings, sibs of the ancestors as possible.  I assess what traits my bitch possesses and those of the dog to whom I intend to breed her.  You also should read books such as The Dog in Motion to understand what good structure really is.  So many people go about breeding without really understanding how a good dog is put together.

Generally, I try not to double up on a trait, such as curled tail vs straight, good tailset vs bad, strong bone vs light bone.  I try to decide if the trait is polygenic or not, such as leg length.  If the trait is polygenic, then I can get traits "in between". - such as tailset - if I breed a good tailset to one not so good, I will get tailsets from good to bad and everything in between.  Very few qualities of structure actually are a matter of one or the other, generally you will get a blend.

I try to avoid bad traits that are difficult to get rid of, such as east-west fronts.  Some things you can improve in one generation, such as density of bone.  Some things take many generations to improve, such as rears and side movement.  Some traits will pop up where they were not expected.  In this case, you should not expect either a big improvement of that trait, or a lot of harm from it if it was not desired, in future generations.

What I do when I have all the information, or as much as possible, is to put all of the traits in a mental "box", shake them, and then imagine what traits COULD fall out.  This is what I can expect in my litter. I hope for the one puppy that has all that I bred for.  

Don't always breed to the "perfect" top stud dog.  I have found it is more beneficial to breed to a less known dog with the traits that I want or need.  Sometimes the dog with exceptional virtue is overlooked in the show ring because of a strong fault or two and the top show dog really only approximates mediocrity - he is easy to put up because he lacks faults, but that does not mean that he possesses virtue.  I also prefer to stay with dog about whom I know a lot so that I don't get any health or structure surprises.

Also, there is an art to breeding dogs.  Call it a gut feeling.  If my gut says "no", the breeding generally then hasn't worked out, even if intellectually speaking, the breeding should have been great.

Check out the writings of Jon Kimes on his website: www.jonkimes.com.  He makes a lot of sense and has a lot of great information about breeding in general terms.

Good luck to you in your endeavors!

Rubad

"Is ita sum simple total of traits of mother and father?"

It's a weighted analysis not just of themselves, but what the parents have produced, that is also congruent of their particular phenotype.  For simplicity, you could suppose that a parent that only produces 1/4 progeny that is like itself, would be less prepotent, or homogenous for a genotype, than the parent that produces 3/4 of it's progeny in its likeness.  Each producer one generation back, only "weighs" half of its offspring's worth.

Although Rubad's dissertation is interesting, too much emphasis on structure for my taste.  Character matters most to me, therefore matters of conformation etc. are generally only an intutive part of my decision process.  My preferred emphasis would be -- an approximation of "faultlessness" in structure, and "virtuous" in temperament regards.  A single temperament fault can ruin total working potential, and greatly disrupt future generations, a high tail set only ruins showing potential, and much easier "fixed".  Because gene segments involved in character selection are often "linked" with certain physical characteristics that compliment such, in physiological respect, evolution can approximately guide itself in appropriate fashion.