Are mixed breeds genetically healthier than pure breeds?

Interesting. Thanks for sharing.

Very Interesting.

My take away on this is that a person could at least "theoretically" have a better chance at avoiding genetic diseases by adopting a pure breed if, and only if, the lineage was well researched.

I came to this conclusion simply because the mixed breed and designer breeds are less likely to have the required info available.

There is another avenue to deepen the gene pool. That is to involve dogs of the same breed, but from other countries.

We had a Wheaten Terrier that developed a protein wasting disease, which is something Wheatens are prone to develop, regardless if they are from champion stock.

Our current Wheaten is 50% American stock and 50% from Ireland. Statistically this is a sample of one, and of absolutely no significance. But the dog is 6 years old and has not had the health problem our other Wheaten had.

JRS & B wrote:
Very Interesting.


There is another avenue to deepen the gene pool. That is to involve dogs of the same breed, but from other countries.

Out-crossing has its own set of problems, but that's another thread.
Assuming that a dog won't have disease X because it's from another "stock" is not effective.

What is effective, is doing the necessary health checks before even considering breeding an animal. Depending on the breed, this might include X-rays for hips and/or elbows, eye exams, or any number of DNA tests.

The Orthapedic Foundation for Animals has a fairly decent guide to what tests each breed should have.
Tests by Breed

a guide to DNA tests suggested by breed can be found here. This is only a guide, not an authoritative absolute.
DNA by breed

Some breeds have inherently specific diseases, I think almost all "breed" dogs have things that they're prone to. I've had 4 Dobies, our favorite dog. All were just wonderful but were prone to neck issues and didn't live past about 12 due to cancer and other things. Our present guy (12) is also a great dog, super disposition, and smarter than I am and we think maybe Lab, Cattle Dog, maybe some Golden in him. We've spend thousands on skin issues and other things. I don't think there is a cut and dried answer to the question. I think our next dog might be another Dobie. BTW all have been rescues and all just the best.

corgi-traveler - I did not "ASSUME" anything, and I acknowledged my particular current case was statistically insignificant.

There were five of us friends/co-workers who had Wheaten Terriers. We all got our dogs from totally unrelated breeders from different areas of Michigan, with mine actually coming from out-of-state. Two of the five had the protein wasting disease, including my West Virginia Wheaten.

My gut feeling is that this high incidence, for what I believe is a pretty rare disorder, did not come about totally by random. But rather the results were skewed by in-breeding in various forms and degrees over a long period of time.

The idea is to go back in time before the problem occurred. If the problem has not yet manifested itself in Ireland, then there is nothing to lose and everything to gain by going outside the country. I think of it as being somewhat akin to doing a "restore" on a computer.

The pure bred dog world is now multi-national with genes being moved all round the world.

Protein losing nephropathy (PLN) and protein losing enteropathy (PLE) are serious health problems that have been identified in Wheatens in North American and Europe.

A small number of Wheatens have now been diagnosed with, or suspected of having, PLE and PLN in the UK.

Soft Coated Wheaten Terrier Club of GB

BCSnob - I totally agree that the dog world is multi-national. But a "small number" diagnosed or "suspected of having" a disease is not the same as 40% (2 out of 5 in Michigan), which was my personal experience.

I would add that 15 years ago many vets did not know what PLE and PLN were. And when we pursued it, based on my friend's experience, the diagnosis at that time cost about $1,000, maybe more. So I believe the disease has a much greater foothold in the US than it has in other countries because many people did not know what they were dealing with and would not arbitrarily spend more than a thousand dollars of a customer's money doing their own original research.

I have no idea if the experience in Ireland (which is where the dog originates, not GB) is better or worse than GB, but I am confident it is better than in the US.

You're 40% is not representative of the incidence rate (affected) in the entire gene pool. Four or five dogs is way too small of a sample to represent the entire gene pool.

According to Wheaten Health Initiative 2009-13 the estimated incidence rate in the UK is 2% (where the 95% confidence interval covers 0.2% to 6.8%) which is not that far off of the estimated 5%-15% in the USA (AKC Canine Health Fund). I suspect as better diagnostics become adopted we'll find the incidence rates are similar in North American and UK/Ireland. I'll bet you'll find the gene pools of Ireland and the UK are very similar, like the gene pools in MI, IN, IL, and WI for example.





Instead of guessing we could look for the information from informed sources.

The answer you're looking for can be found in a recent copy of the SCWTCA news letter (page 8). In the USA the breakdown for 880 dogs tested is 33% normal, 48% carrier, and 19% affected; in the UK/Ireland the breakdown for 100 dogs tested is 65% normal, 23% carrier, and 12% affected. I don't know if 100 dogs from the UK/Ireland is sufficiently large enough sample to estimate the rates in the entire population. The rates in the USA match what is predicted for an autosomal recessive trait.

Typically when a new genetic test becomes available the distribution found by the testing is skewed from the predicted for the type of mutation (i.e. autosomal recessive) due to too few samples; once the number of samples is large enough to represent the entire population the data matches the predicted. When the test has been well adopted the new test results no longer follow the predicted due to a sampling bias (testing is performed only for breeding purposes not randomly).

I agree my sample was small, but it was "reasonably" random and unbiased. It does not tell me anything with certainty, but it tells me there could be a problem. As far as comparing on estimate to another estimate, well they are both just that, estimates.

Mathematically, an estimated incidence of possibly 15% is still 750% bigger than an estimated incidence of 2%.

Figures lie, and liars figure. As a statistician friend of mine often said, statistically speaking, the average American has one breast and one testicle, but I have never met anyone yet who meets that description.

JRS & B wrote:
Mathematically, an estimated incidence of possibly 15% is still 750% bigger than an estimated incidence of 2%.

Read the latter part of my last post. It has the most up to date genetic testing results (with a link to the source) which show 19% in the USA affected as compared to 12% affected in the UK/Ireland. Clearly, the inital estimate of 2% in the UK was a bit low compared to the more recent 12%.