Finding Genes for Complex Disease Traits Using Population Structure, Jerold Bell – conference notes (Dr. Ostrander’s notes and presentation will be available as soon as CHF provides them)

 

Healthy breeds and breeding recommendations

What can we do to maintain healthy breeds?

 

Genetic diversity

            Many breeders are concerned with breed-wide genetic diversity

            Some breeds propose only assortative mating and outbreeding to those least related

            Selection, not the types of mating affect breed diversity

The health of the breed is not related to inbreeding coefficients and the size of the gene pool.

 

What deleterious recessives are in your breed?  This is what is important and can often be expressed more often with a smaller more closely related gene pool.

 

How do we work to move against these genes?

 

The popular sire syndrome is the largest problem affecting our breeds today.  The loss of influence of other quality males in detrimental.  And popular sire syndrome can be worse than founder syndrome.

 

Genetic diversity = breeder diversity

It is the varied opinion of breeders as to what constitutes the ideal dog, and their selection of breeding stock that maintains breed diversity.

 

Developing a healthy program:

-Predictability is the hallmark of genetic disease.  Our role is early diagnosis, intervention and prevention

            -“Just don’t breed those two together again” – still propagating deleterious genes

            -“Breed to an unrelated dog and it won’t happen again” – same as above

-“Spay and neuter your animals and restart with someone else’s lines” – you may end up with the same genes.  Or with too many unknowns.

Breeders want to know what they can do to continue their own lines.  Can use relatives to an affected dog carefully and be aware of diagnosis, intervention and prevention.

 

Breeding goals

            Maintain and enhance the quality of the breed

                        Do not limit the genetic diversity of the population

            Genetic disease control

                        Do no produce more affected animals

Decrease the carrier frequency of defective genes – use genetic tests when

possible, if no tests do sibling/aunt/uncle research.

Managing dominant genes

            Replace affected breeding dogs with normal siblings, parent or prior-born offspring

            Ideally don’t want to breed and produce more affected dogs

            *examples of dominant diseases: primary hyperthyroidism, some cataracts, DCM