Musings on Breeds- Retrospective

As many of you know, I agreed to begin helping at BetterBred last August 2017. At the time I thought I knew so much about VGL’s canine diversity testing, and how to properly implement it. What has happened in the last 7 months or so has been a real broadening of that knowledge and understanding.

My scope of perspective has changed for many reasons, but one of the biggest impacts from this time has been getting to know each breed.  Each is unique, with varying levels of bottlenecks, remaining diversity, and distribution of those genetics.  It’s been wonderful to learn each of their unique histories and stories behind them.

The most worrisome population is the Doberman breed, where longevity is dropping and dilated cardiomyopathy (DCM) is a major issue (among other debilitating illnesses). Their breed average OI is .18. Their breedwide IR is also very high at .08– meaning most dogs are inbred with common bottlenecked genetics. Most share the same DLA haplotype, and very few other DLA types remain in the breed.  Recently some higher OI Dobermans have been added to our database; it has been very exciting for us and that breeder community.  We are also pleased to see people running full litters and using the information to make informed selections for breeding.  

Standard Poodles are not in much better shape with a breed average at .23 OI.  I was recently discussing Standards with a breeder in another breed, she is hoping to get another Standard Poodle. She listed a plethora of conditions all her other attempted breeding standard poodles had, including AD and cancer (and more). They could rapidly get to the place the Dobermans are in without conscientious people working to keep the breed pool broad and redistributed. They might already have been there if it were not for John Armstrong’s suggestions in the 90s and the Standard Poodle Project created in the 2000s.

Flat Coated Retrievers have a breed initiative and their national club offsets the cost of the testing to encourage their breed to test.  Their average OI is .26, with a relatively low IR of .03 breedwide.  They have a high incidence of cancer and have not a lot of diversity at the breedwide level, but thankfully they have a little wiggle room.  With their effort and discovery of different genetics in their population, I am hopeful for them and their stunning dogs.  

Then there are bottlenecked breeds who have managed to distribute the genetics they do have fairly well….some population examples are the Biewers and Shiloh Shepherds.  The bottlenecked breeds that have fairly well distributed genetics tend to enjoy better health overall; they have done a good job maintaining and distributing what they have for the most part.  Because of this their breedwide average OI is higher, because few alleles are very common, most are neutral. Those breeds have health issues, but not quite as much as the bottlenecked breeds with very common genetics.

Lastly, viewing the breeds (varieties) in the very best shape: Havanese and Miniatures Poodles. They have little disease (and most of us know that about them). There are health issues here and there, but not as high at the breedwide level; you don’t go in their breed groups and see post after post about common health issues (again though they have some). Those breeds (varieties) just have to maintain what they’ve done! Keep the diversity of genes.

While OI is no guarantee of health or caliber of a dog, on the breedwide level it is very informative.

Each breed population is unique and has different properties to their breedwide genetic diversity.  Each breeder community has a different culture and willingness to work together.  Many have united with a common goal, and it’s inspiring to see.  No matter where your breed falls, it’s important to know where you may want to go and what you should consider for the continuation of it.  

Kudos to you here who are working to use this as one more tool in your arsenal for the selection for health, temperament, structure and drive in your breed. The impact of our choices will have long-term effects and a legacy. Of course, those factors and SELECTION for them will always be important for us.

For those interested, you can see a list of the current breeds on BetterBred and compare them on our website here: Breed comparisons

For those who have not seen it, the following is a quick reference for Breeding for Diversity with BetterBred. 

A few useful definitions:

Outlier Index – The Outlier Index (OI) is a measure of how unusual for the breed a dog is. It takes in to account the rare, common, and neutral alleles a dog has.  OI gives breeders a measurement to help select away from bottlenecks and uses the breed-wide allele frequencies gathered at UC Davis. This measurement helps retain diversity within the breed.  Breed for higher than breed average in order to increase and redistribute the genetics of the breed. The higher the OI, the more atypical a dog; the lower the OI, the more typical.

Average Genetic Relatedness (AGR) – A measurement designed to show you how related your dog is to all the dogs of the same breed in BetterBred.  It is similar to a concept called mean kinship in genetics.  A dog’s AGR is based on how likely it will share genes with every other dog in the BetterBred database and is based on calculations from a paper written in 2002 by Jinliang Wang.  Each STR, and STR frequency, is used in the calculation.  A dog with a low AGR is very unrelated to the rest of the breed on BetterBred. A high AGR indicates the dog is highly related to much of the population on BetterBred.  Breed for lower than breed average AGR to select away from genetic bottlenecks.

Internal Relatedness (IR)–  a measure of genetic diversity within an individual that takes into consideration both heterozygosity of alleles at each STR loci and their relative frequency in the population. Therefore, IR values heterozygosity over homozygosity. IR values are unique to each dog and cannot be compared between dogs. Two dogs may have identical IR values but with very different genetic makeups.  This is an inbreeding measurement.  The higher the number, the more inbred (homozygous), the lower the more outbred (heterozygous).  This is included on the UC Davis certificate for your individual dog, but does not predict what the dog will produce with another dog.

 

 

Rebekah