(See link below to extensive article.)
By Judy Huston
The Geneticist’s Pedigree is the foundation of Dr. George Padgett’s work. Detailed information can be found in his book, Control of Canine Genetic Diseases. Using a geneticist’s pedigree is a very important step after the establishment of an Open Registry. The White Shepherd Genetics Project has the Open Registry which includes reports of diseases and symptoms submitted by breeders and White Shepherd owners. Now, we need geneticist’s pedigrees to help us use this registry in the best possible way.
Think of Progeny as visual tracking.
When you look at a GenPed, you will see one dog with an arrow by the name. This is called the Proband. It is most often indicating that this is the dog you are building the pedigree around. In these “disease” GenPeds, it is simply the first dog I entered on the pedigree, not the first one affected, nor the most important dog. Squares indicate males. Circles indicate females. A diamond indicates sex unknown. A line through any of them indicates deceased. A symbol filled in black means affected. Half-filled in means a proven/defined or obligate carrier. The percentage underneath the call name means this is the risk factor for the dog carrying the trait being tracked on this pedigree. A hook through a line means they are not related. A line over the top of a name is called a Shadow and is used when a dog is on the pedigree more than one time, but they are only counted once. All related affected dogs will appear on one pedigree so they can become quite large. When, as in the case of the EPI pedigree, there are dogs reported that do not connect to the majority of the dogs on the pedigree, they will be shown separately. With the Megaesophagus pedigree, they are all on the same GenPed.
For now, we are doing pedigrees that track one disease at a time. Later, we will try pedigrees that show up to four diseases on one GenPed. Each disease will be in a different color and take up ¼ of the symbol. This process can help us identify linking diseases. On one we are tracking eyes, hearts, and hernias. On another, we would track IVDD, LS, DM, and IBD – because this is the way we can see if they are associated. So we would track those together and could see that this usually goes with that. That’s the type of helpful linking information we can get.
For now, I have a Progeny software program and the WSGP recently bought one for Lynda Proulx. We will be working on these pedigrees so you can contact either of us with questions.
To read an extensive interview I did with Dr. Melissa Cox, our former White Shepherd Genetics Consultant, on the use of a Geneticist’s Pedigree, click on the following link.
Interview with Dr. Melissa Cox
These pedigrees will be updated at least as often as the charts are updated.
You will notice that the GenPed has the call names of dogs. Look at the spreadsheet to see not only the registered names of the affected dogs, but the call names and registered names of almost every dog on this pedigree. (A dog that doesn’t seem implicated in the disease may not be on the spreadsheet since there is no risk associated with that dog.) Since the spreadsheet is in Excel, you can sort it any way that suits your research. Right now, it is sorted in descending order by the percent of risk each dog carries for Megaesophagus. All the affected dogs are listed with their sires and dams on the same line, but each dog is also listed individually with degree of risk and shows which affected dog(s) determined their degree of risk.
Important fact to keep in mind, the pecentages are based on reported affected dogs. We know we cannot assume we have all the dogs that were/are affected on this pedigree, but this gives us a pretty good idea where the carriers are.
You must factor in that this pedigree only shows four sibling relationships to affected dogs that I was personally aware of, but every sibling of every affected dog has a 66.6% risk of being a carrier, so you need to know about siblings. Keep in mind that we are showing 26 affected dogs and if each of them had only four littermates, that would be another 104 carriers at the 66.6% risk factor. And, for every carrier you see on this pedigree, their siblings are also carrying a risk for being a carrier. The approximately 50 parents all have siblings and if you assume each have only four, you would have another 200 possible carriers. You need to do your homework to find these dogs. (Obviously, only a small percentage of the potential carriers I just mentioned would be in the breeding pool, but they are important to know about.) You can also ask any of us who have the Breeder’s Assistant Pedigree Program to help identify siblings, half-sibs, etc.
So, good luck with your research.
Intuitively, I think these GenPeds will make a huge difference for all of you breeders and White Shepherd enthusiasts once you become familiar with them.
IMPORTANT NOTICE/DISCLAIMER: Every effort was made to make this pedigree and spreadsheet as accurate as possible. If you see an error, or what you think is an error, just e-mail one of us at firstname.lastname@example.org or Lynda Proulx at email@example.com and one of us will explain it or change it as the case may be. This is an evolving process. Right now, these are complicated and time-consuming and I think it will take all of us working together to make them as accurate and as powerful a tool as they can be. In my opinion, they are the stepping stone to the next level of health for our breed.
RISK OF BEING A CARRIER IF RELATED TO AN
(AUTOSOMAL RECESSIVE TRAIT**)
Degree of Minimum
1 = Parent, progeny 1 100.0%
2 = Full brother/sister 1 66.6%
3 = Grandparents, aunts, uncle, 2 50.0%
4 = Niece, nephew 2 33.3%
5 = Great-grandparent, first cousins 3 25.0%
6 = Great-great-grandparents, first - 12.5%
7 = Great-great-great grandparent, first - 6.25%
*This chart can be found on page 63 in George Padgett’s book, “The Control of Canine Genetic Disease.
**This chart is used for Autosomal Recessive Traits as well as Polygenic Traits—the risk for the Polygenic Trait will be “at least” this percentage.
GenPed Megaesophagus - for download (revised October - 2007)
Spreadsheet Megaesophagus - Excel for download (revised October - 2007)
Spreadsheet Megaesophagus - for download (revised March 8 - 2007)
GenPed EPI - for download (May 1 - 2007)