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  Genetics Lesson




A little lesson in Genetics...

Lets use an Umbilical Hernia as an example.  (Umbilical Hernias can be genetically passed on or could happen when the dam bites the umbilical cord to short on a newborn puppy, for our example here, we'll assume that we've only got the genetic kind.)


Lets use an Umbilical Hernia as an example.  (Umbilical Hernias can be genetically passed on or could happen when the dam bites the umbilical cord to short on a newborn puppy, for our example here, we'll assume that we've only got the genetic kind.)

We've got a sire and dam picked out, neither one of them has an Umbilical Hernia, so we should produce a litter of puppies that have no Hernias, right?  Ummm... maybe not...
















Our sire and dam each have two possible genes to contribute to each puppy.  The "H" stands for the gene that can produce a hernia.  The "h" stands for a clean gene, one that doesn't produce a Hernia.


Lets say that we have a litter of four female puppies.  That means that statistically speaking, one of the dogs will probably have a hernia (HH) , two of the others are probably carriers (Hh) even though they don't have Hernias themselves and one of the dogs is probably clean (hh) and doesn't even carry the gene that produces the Umbilical Hernia.  But of course of the three that didn't have Hernias, we have no clue which was the 'clean' dog just by looking at them.


Here's how our litter broke down:
bulletRed collar puppy has a hernia.  (definately HH)
bulletBlue collar puppy has no hernia.  (Hh or hh ?)
bulletGreen collar puppy has no hernia.   (Hh or hh ?)
bulletOrange collar puppy has no hernia.   (Hh or hh ?)


Now lets move move on to the next generation...  Each of our four females has been bred to a wonderful stud dog that we'll call Brown.  Lets assume that this male dog has a chance of carrying the gene for Umbilical Hernia, because we know that one of his parents had a hernia.  (We found that information in our trusty little database.)


Here's how the next generation of puppies turned out:
bulletA few of Red's puppies had hernias.
bulletTwo of Blue's puppies had hernias.
bulletOne of Green's puppies had a hernia.
bulletNONE of Orange's puppies had hernias.


So what does this tell us about our original litter of four dogs, and our sire "Brown"?

It tells us that Yep, we were right, Brown is indeed a carrier and possesses the recessive gene for Umbilical Hernias, so statistically speaking, he can pass that gene on to 75% of the puppies he sires.   (So lets update his entry in the database (Hh) so anyone else that breeds their female to Brown will know that information!)


It also tells us that "Orange" (who has had two other litters previously) is probably not carrying the gene for Umbilical Hernia (hh).  So, if in future generations, we breed her puppies to mates that also don't carry the Hernia gene, we will never see Umbilical Hernias in Orange's line again!


It tells us that Blue and Green are also carriers for Umbilical Hernia (Hh), so future litters that are bred to a male that has a Hernia, or you will get at least some of the puppies with Hernias.


It also tells you that if Blue and Green are bred to a male that isn't a carrier, that although some of their puppies will carry the gene as a recessive, none of them will actually have a Hernia!  In subsequent generations of careful breeding, the puppies will not have hernias, and the number of pups that have the recessive gene will be 'watered down' and the genes for Umbilical Hernia will eventually be flushed out of the gene pool just like we showed with Orange.  

But that's many generations (of careful breeding practices) away.  And if one of these generations is mated with a dog that has a Hernia, you're back where you were, the 'bad' gene is back and subsequent litters from that mating will have to be watched and controlled accordingly.  This is where REALLY good database comes in.  It also means that we have to have honest reports from our breeders, and a commitment from every one of them that they are willing to work at eradicating the diseases that the group chooses to work on.

Is this a lot of work?  You bet it is!  

We were only talking about a little bitty Hernia...  If you're talking about things like Hip or Elbow Displasia, SAS, or a myriad of other extremely painful, or deadly diseases, isn't all this work worth it???


With careful record keeping, and careful breeding, we can focus on a few of the worst diseases and get rid of them, once and for all.  Then we can move on to a few of the lesser diseases and work on getting rid of them... and so on... and so on...  :-)

Ok, so to get back to you and your dog...  

You were asking if you should bother to fill out the survey...  Lets assume that in the litter above, the owners of Blue, Green and Orange never reported back to their breeder to let him know that their dog had (or didn't have!) a problem.  It would leave gaping holes in the database and it would make the breeders job of trying to figure out which dogs were carrying what genes almost impossible.


Reporting back to your breeder and filling out our survey is critical for us to be able to breed better Shilohs.  It takes teamwork and good communication to breed better dogs.  :-)


Soooo...  since you've gotten this far, how about going to our Survey page and filling it out with your dog's information?  Even if your dog is healthy, we still need the information.  And don't forget, if your dog develops any diseases in the future, make sure you come back here and enter the new information.


Dedicated to improving the health of ISSR Shiloh Shepherds.


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All rights reserved. Revised: January 2008

The information on this website was written by ISSR breeders and other concerned individuals, however we are are NOT veterinarians. This information is being provided as a general overview, from information we were able to find about each disease through our own research. These summaries are not intended to be relied upon as medical or veterinary advice, nor do we consider ourselves experts in the veterinary field or in any of these conditions. While we do our best to provide the most up to date information, new research is constantly being done on these diseases. We recommend that you do further study and talk to your veterinarian on any topics you see here, as we cannot guarantee that the information posted here is the most current information available.  This site was originally designed and maintained by Debbie Knatz.