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 Post Posted: Mon Feb 02, 2009 12:13 pm 
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Joined: Sat Sep 27, 2008 10:27 am
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This is one of my favorite articles by Jerold S. Bell, Director of the Clinical Veterinary Genetics Course for the Tufts University School of Veterinary Medicine. I'm putting up the link from the ARC because I think it looks the nicest, but this is used as a primer by many breed associations. The great thing about Dr. Bell is that he is a brilliant geneticist but can still explain complex concepts in a way all of us can understand.

Popular Sire Syndrome and Concerns of Genetic Diversity: ... rome.shtml

Please read the whole article, it really gives a great overview of the issue. But for me, this section really brings home the message, especially for Lacys given the popular sire issues and outcross requirements of the past.

"The perceived problem of a limited gene pool has caused some breeders to discourage linebreeding and promote outbreeding in an attempt to protect genetic diversity. However, it is a fallacy that each dog must carry the diversity of the breed. Studies in genetic conservation and rare breeds have shown that this practice actually contributes to the loss of genetic diversity.

By uniformly crossing all "lines," or families of dogs in a breed, you eliminate the differences between them, and therefore the diversity between individuals. This practice in livestock breeding has significantly reduced diversity and caused the loss of unique rare breeds. The process of maintaining separate lines, with many breeders crossing between lines and breeding back as they see fit, maintains diversity in the gene pool. It is the varied opinion of breeders as to what constitutes the ideal dog, and their selection of breeding stock that maintains breed diversity.

A basic tenet of population genetics is that gene frequencies do not change from the parental generation to the offspring. The gene frequencies will remain the same regardless of the homozygosity or heterozygosity of the parents, or whether the mating represents an instance of outbreeding, linebreeding, or inbreeding. If some breeders outbreed, and some linebreed to certain dogs that they favor while others linebreed to other dogs that they favor, then breedwide genetic diversity is maintained.

The loss of genes from a breed's gene pool occurs through selection: the use and non-use of offspring. If a popular sire is used extensively, gene frequencies, and the gene pool can shift towards his genes, limiting the breed's genetic diversity. On the other hand, dogs that are poor examples of a breed should not be used simply to maintain diversity. Related dogs with desirable qualities will maintain diversity and improve the breed.

Breeders should concentrate on selecting toward the breed standard, based on ideal temperament, performance, and conformation, and should select against the significant breed related health issues. If breeders continually breed healthy, superior examples of their breed and avoid the popular-sire syndrome, the genetic health of the breed can be maintained."

And for those wanting another friendly explanation of matador breeding (a.k.a popular sire syndrome), here's another article:

"You must be a very small minority no matter who you hang around with. Maybe you should start a magazine, Vegetarian Hog Dogging Monthly, find some like-minded individuals."
- Inspiration for my next project from TBH

True Blue Lacys:
More Lacy Pics:

 Post Posted: Mon Feb 02, 2009 12:24 pm 
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Joined: Sat Sep 27, 2008 12:04 pm
Posts: 1677
Location: Burnet County
Absolutely an awesome read. Whether you are new to breeding or been doing it
for decades, this is information all breeders should take the time to make themselves familiar with.

Thanks Julie!!!!


M.D.Brooks Founding Member & Breeders Committee Chair
Bayed Blue...Bayed True...That's A Lacy Dog
If You can't keep up with the Lacy Dog...stay on the porch!

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