Dwarfism in the Great Pyrenees & The Dwarf Marker Project with

 UC Davis School of Veterinary Medicine

Lead Contact:   Peggy Watson - Pyrstaf@aol.com

4/2007 - DWARF STUDY UPDATE

In late April, Dr. Mark Neff’s laboratory at UC Davis reported the achievement of an important milestone in understanding the genetic basis of dwarfism in Great Pyrenees.  The research team had recently compared the DNA profiles of affected Pyrs (n=12) and unaffected control dogs (n=19), and they found a DNA marker that is highly correlated with the defect.  Each of the affected dogs were uniform at the marker on chromosome 33, whereas none of the unaffected dogs had the same genetic signature.  The probability of obtaining this result by chance is less than 0.000001 (for context, p < 0.05 is the typical threshold for a significant finding in biological research).

For the laymen among us, the result means two things.  First, it supports the prediction that dwarfism in Pyrs is controlled by a single gene acting recessively (hence two copies of the mutation are needed for a dog to be affected).  All affected dogs had two copies of the DNA marker.  Second, the progress substantially reduces the problem of identifying the causative mutation (from 2.4 billion letters of DNA to slightly less than 2 million letters).

To identify the individual gene responsible for dwarfism, the researchers at UC Davis hope to collect additional samples from affected and unaffected dogs.  Their target is DNA from an additional 10 affected dogs (to essentially double the power of the mapping approach).

Please contact Peggy Watson if you know of any dwarves or unaffected dogs from which blood or cheek swab samples can be collected.  Peggy has the submission information for blood samples and has swabs for the cheek collections.  You can reach her at pyrstaf@aol.com.

UC Davis is underwriting the blood collections at $15 per dog and is providing free shipping of the samples.  To insure that no one will be unable to submit samples because of cost, the GPCA BOD has authorized reimbursement for costs beyond the $15 allocated by UC Davis.

With our help, the researchers have taken an exciting first step toward a DNA test that would allow us to eliminate dwarfism from the Pyr gene pool.  Let’s continue to support the research by providing the much needed DNA samples.  This will in turn allow the research team at UC Davis to progress the study to a successful conclusion, and ultimately ensuring the health of our dogs.  

January, 2007

The members of the GPCA Health Committee are pleased to announce the start of an initial project to search for a genetic marker for the cause of dwarfism in Great Pyrenees.  Dr. Neff at UC Davis will be conducting the research and Peggy Watson is the GPCA contact person  for this project.  The HC recommended the project and funding to underwrite the collection of samples to the GPCA BOD.  We are pleased to report that the motion passed the BOD unanimously. 

Recent advances in genetic research allow Dr. Neff to proceed with a study based on three groups: one group of affected Pyrs (dwarves), a second group of Pyrs related to the dwarves, and a third group of non related Pyrs.  Participants have been identified and contacted.  More  detailed information will be provided in an upcoming article that will be posted on the website and in the BULLETIN.

This is an important beginning to a question that has been concerning GPCA members and breeders for many years. We hope that once a marker is found that it will lead to the development of a simple screening examination that will assist breeders in planning their litters to prevent this problem that has existed in our breed for generations.

We are quite excited about this opportunity.

Flo Laicher, HC Chair

Please check back for detailed information.