Biology, Inbreeding, and the Kishu Ken

Inbreeding can be a scary word, but it is not necessarily a scary thing. Inbreeding is why our purebred dogs are predictable in type (form, appearance) and temperament (function, personality.) It can, however, become problematic and counterproductive to breeding healthy, happy dogs when too many deleterious alleles become fixed (existing in a homozygous state) in the population.

The Kishu Ken is a medium-sized, prick-eared, erect-tailed dog most often exhibiting a dense, white coat. They are known for their tenacity and endurance. These are traits that have been "fixed" or mostly-fixed in the Kishu Ken population through selective breeding: removing traits that are deemed undesirable while retaining those that are.

Modern Kishu Ken have gone through a handful of bottlenecks over the last century since they were standardized that have fixed ​certain traits - seen and unseen - in the population. First, when they were standardized and dogs were given registration numbers and entered into the closed studbook system (by nature of what a closed studbook system is.) Secondly, a bottleneck was created to create breed type (for show dogs or hunting dogs - in different directions) in the population. Lastly, trends through the decades and popular sires have continued to diminish the available diversity in the breed.

Recently, the National Kishu Club coordinated with Embark Veterinary to investigate the biology of the Kishu Ken breed due to concerns of allergies, hypothyroidism, and autoimmune illness that have been seen. All three of these types of illnesses are linked to immune function, and immune function has been linked to overall genetic diversity, so it was worth it to investigate what was going on, biologically, with our breed. 

5 dogs had already been tested with Embark. These dogs represented a decent mixture of lines, but were not enough to make many assumptions about the breed. 10 more kits were acquired and dogs representing very outbred pedigrees on paper were selected to participate in the study. 7 such dogs have been selected so far. The National Kishu Club has 3 more kits to distribute to outbred dogs (on paper.)

Greyed out names represent dogs who are not part of the breeding population.

The findings so far have been that there is a minimum genetic relationship coefficient of around 25%. This means that among all of our dogs tested, the equivalent genetic relationship between the LEAST related dogs would be about as "distantly" related as a grandparent is to their grandchild or half siblings are to one another in a totally outbred pedigree.

Somewhat concerning is that some dogs shared even more genetic material with one another than they shared with their own offspring while still appearing to only have distant ancestors in common, and dogs who had very few common ancestors far back in their pedigree were as "related" (per genetic relationship coefficient) as full siblings or parent-offspring. 

So far, the highest CORs (relationship coefficients) belong to dogs with past connections to a particular influential show line of Kishu Ken. The findings so far indicate that this is a BREED/POPULATION ISSUE in general, not the fault or failing of any one kennel or breeder. Geography does not appear to be a significant impact in these results. Embark has found that a dog from lines with pedigree ancestors that have been in the USA since the 1990s had a COR of 49% and 50% with 2 recent imports from Japan (2011, 2014), meaning the ancestors of all 3 dogs were very closely related.

Only one dog in the population so far (another recent Japan import) has CORs below 30%.

Another thing Embark testing has allowed Kishu owners to investigate is the MHC loci that the lab tests for. MHC diversity (or lack thereof) has been directly linked to autoimmune illness such as Addison's Disease (found in the Kishu Ken), and so while Embark's current format is rudimentary and may not help inform breeding decisions, it is good data to keep. So far, the majority of Kishu Ken have been evaluated as "high diversity" at their MHC loci per Embark, but unfortunately there has been no overt difference between the DLA breakdown of a dog with autoimmune illness and those those who are healthy. This information cannot yet be used as a surefire way to breed healthier dogs, but it is interesting to note where dogs are similar and dissimilar - where alleles appear "fixed" in all dogs tested so far and where diversity is still found.

A color-coded breakdown of the alleles at MHC loci locations from some of the Embark-tested Kishu Ken.

While this information is still rather rough, with too few data points to make very sweeping statements or summaries, there is one thing we can certainly take away from this: current pedigree data available in English is too limited to determine genetic or familial relationships accurately. Two dogs who appear completely outbred on paper may be very close genetic matches in reality. 

One immediate way to act on this information going forward is to genotype all dogs with Embark to be able to generate genetic CORs on any dog to be bred so breeders can make informed breeding decisions. Another way, which may take much longer, is to continue to bring pedigree data to English so our paper pedigrees are more reliable.

Please consider using the Kishu Ken Pedigree Database to submit your dog's data (even if they are not used for breeding) and testing your dog with Embark Veterinary. Every little bit of information helps us develop a more complete picture of our population. If you are a Kishu Ken owner who is interested in testing your dog, please reach out to the club - there may be something we can do to help you.

Written and edited by C.j. Hammond