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by darylehret on 03 April 2009 - 03:04
Minimizing Inbreeding by Managing Genetic Contributions Across Generations
It was long believed that the lowest rate of inbreeding in populations with unequal numbers of breeding males and females was achieved by a breeding system in which a son replaced its sire and a daughter replaced her dam (Gowe et al. 1959). Thus every dam has one breeding daughter, and as many dams as sires have also one breeding son (such dams are termed dams of sires hereafter). This breeding system has the effect of reducing the variance of family size, and it is an extension of the classical solution for equal numbers of breeding males and females (Wright 1938). Wang (1997) showed that the strategy of
by darylehret on 03 April 2009 - 03:04
Gowe et al. (1959) could be significantly improved upon, by not allowing the dam of sire to also have a breeding daughter, but instead allowing another dam to have an extra breeding daughter. Such strategies are effective and have provided the basic framework for successfully managing populations. Yet they consider only one generation at the time of selection and mating.rate of inbreeding for populations with unequal numbers of breeding males and females, by optimizing selection decisions considering multiple generations. The development of pedigrees over multiple generations can be modeled by using the concept of long-term genetic contributions (Wray andThompson 1990; Woolliams et al. 1999; Woolliams and Bijma 2000). In this study we show that management of long-term genetic contributions of breeding individuals across generations is the key to minimizing the rate of inbreeding.
by Two Moons on 03 April 2009 - 03:04
I left my hip boots in the boat.
by MVF on 03 April 2009 - 20:04
Obviously, some gene pools are indeed too small to be healthy. (Consider the Laekenois.) And all legitimate efforts to preserve species include serious outcrossing.
I dare to say that the mathematics of population genetics is so complex that it would be very hard to prove that cross-breeding gsd's (with its worldwide pool of genes) is a necessary or improving strategy.
But I don't myself see how it could hurt the breed (as they products of such breedings are no longer members of the breed, and if it doesn't work out, one does not cross back). But in our world, the cross breeders would have to take extraordinary steps to make sure the offspring have good homes for life. No matter how spectacular, no mutt has good odds in the pound.
by Mackenzie on 04 April 2009 - 06:04
At the end of the day, was the four family system such a bad thing. Remember the 1972 Sieger Marko v Cellerland was sired by an HGH male.
regards
Mackenzie
by Mystere on 04 April 2009 - 15:04
by Mackenzie on 04 April 2009 - 15:04
Kind regards
Mackenzie
by Trafalgar on 04 April 2009 - 20:04
Example: Dutch Shepherd x Mal crosses are my favorite dog type at the moment.
In my opinion the quality of a dog is directly related to the characteristics it posesses not it's membership in a particular group.
The whole notion of "purebloodedness" is elitist (in the obnoxious not the intellectual sense) and immoral to be frank.
The best that can be said for "breeds" is predictability (to the extent that one can predict).
The worst is what they say about the people who run on and on with nonsense about the sanctity of "purity" and "standards".
Nothing wrong with breeds. But there IS something wrong with people who are fierce defenders of this so called purity.
"When will we ever learn.....when will we ev..ver learn."
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