IDASH Pedigree Analysis

IDASH Pedigree Analysis

Rev. March 2016

This service is an outgrowth of the private pedigree analysis service ASHGI President, C.A. Sharp, first offered in the early 1990s, initially for Collie Eye Anomaly and later for a broad range of hereditary diseases, dental faults, and disqualifying coat colors.

The service depends on data.  Some has been gleaned from open health registries in the US and Europe but most comes from breeders and owners.  The International Directory for Australian Shepherd Health (IDASH) maintains two genetic databases.  One is the IDASH Open Health Database (OHD) which holds data from publicly available sources and documented information voluntarily submitted by dog and litter owners.  The other is a confidential database comprised of data collected before the advent of the OHR or which people opted not to submit as “open.”  ASHGI will not provide confidential information about specific dogs in a pedigree nor will we provide analysis reports for anyone other than the owner of a dog or breeder of a litter.

For detailed information about genetic issues in the Australian Shepherd breed, please refer to the Genetics Information section of our website (click on the menu above). ASHGI tracks a variety of traits for pedigree analysis.  Most are common inherited diseases.  Some less common and even rare diseases are listed if they are sufficiently serious that owners should be aware of potential in the pedigree or there is a DNA test available.  The list will change from time to time based on fluctuations in disease frequency or new knowledge of diseases or availability of DNA tests.

The analysis is based on two types of calculations, a risk score for each trait and a coefficient of inbreeding (COI).   Risk scores are on a 0-10 scale, with 1-2 being low, 3-4 moderate, and 5-10 high risk. Since we are largely dependent on voluntary submissions our database cannot reflect every incidence of a given trait. Risk scores may be to some degree understated.  COI is a measure of inbreeding.  For more detailed information on COI and how to use it click HERE.

Zero scores are not listed as a number.  The pedigree analysis certificate will use  for no known background.   This means we either have no data for that trait in the dog’s pedigree or, if there is a DNA screening test, either the dog or some or all of the its progenitors tested clear.

Trait scores are calculated through the fifth generation behind the subject dog. They are based on a modified percentage of ancestry calculation, not a probability prediction.  Scores  indicate the amount of background for the trait in the pedigree, weighted by how often and how far back a dogs connected to the trait  appear as well as its degree of that connection.  For a fuller explanation of how the scoring is done click HERE.

Scores are not evidence that the dog will have a trait, but an indicator of whether it is likely to carry genes for it.  They may give a dog owners some indication of their dogs’ family health histories, but it would be better to get specific information on individual dogs in the pedigree from the breeders and owners of those dogs or via the OHD.

Pedigree analysis is a tool for breeders.  The scores provide a consistent method by which you can compare pedigrees and determine whether two dogs are a complementary for the traits listed.  Every dog has some level of potential for some health issues; seeking dogs with all zero scores is fruitless.  The scores can be used  to reduce risk of producing unwanted traits through informed breeding decisions. A score of 3 or higher is reason for concern.  Try to avoid crosses that score in excess of 5 for any serious disease, though with some diseases the average score is sufficiently high that it is necessary to breed high-risk dogds.  The IDASH pedigree analysis will enable you to do so judiciously.

While we do not do analysis on planned litters, if both parents have had IDASH Pedigree Analysis you can come close  by averaging the parents’ scores.

If a dog scores 3 or more for a trait for which  a DNA test is available, we strongly recommend that you have that test done so you will know the dog’s genotype for that trait.  . (See the ASHGI Health Screening Protocol.)

All traits are not equal and you need to consider structure and behavioral traits in addition to those covered by pedigree analysis.  For a detailed treatment of how you can do this click HERE.

Given that the average score for some traits is 4 or above, if your dog exceeds the average, attempt to reduce the scores for puppies to below the average whenever possible. If multiple traits are a concern in any particular dog, you are unlikely to be able to reduce risk on all of them while still selecting for key desired traits. The higher risk traits should be prioritized based on their health impact.

If you are interested in having pedigree analysis done on a dog you own or a litter you bred you must first create an IDASH login.  If you already have a login, click HERE.