[BREEDS][DISCUSSION] Dog genetics! Analysis of 100 DNA results posted to Reddit (x-post r/DoggyDNA)

[doppelgank]

I'm a mod over at /r/DoggyDNA, a sub where people can post their dogs' DNA test results. Because I'm the type who thinks data analysis is fun, I've been keeping track of the all the DNA results people have posted here, in hopes that eventually it would be useful. You can view the spreadsheet I made on Google Sheets here. I recorded the breeds detected in each result, and then basically information that indicates the degree to which and how far back the reports determined the dog to be mixed. Since we now have exactly 100 results posted, I thought that would be enough to make for some interesting analysis in aggregate, and that /r/dogs might be interested in what I found!

So, out of 100 results:

• We've had just 4 purebred results - which makes sense, since most people use the test to unravel the mysteries of their mutts. There was one more result where the dog was a possible purebred that had just been bred away from the original lines.
• There have been just 2 crossbreed results in the usual sense, where each parent was a purebred of a different breed. If you expand the definition to beyond the first generation (e.g. 75% of one breed and 25% of another), there were 4 crossbreeds. One more was almost a crossbreed except for one undetermined great-grandparent. This is good to keep in mind when you think a dog is a mix of just two breeds - only 5% of the dogs tested fit that profile! An additional 36 out of 100 dogs had one purebred parent.
• In fact, the average minimum number of breeds the test estimated the dogs to have in their ancestry (under the logic that if a dog's great-grandparent shows up as a "mixed breed" it has at least two breeds in it) was 7.53, median 7. The average number of breeds the test could actually identify (meaning they were in the past three generations and therefore made up at least 1/8 of the dog's DNA) was 2.62, median 3. The highest number of breeds identified in a single dog was 6.
• As for the percentage of breed ancestry the test could nail down, and therefore a decent measure of how mixed the dogs were, it could determine 100% of the dog's genetic breed makeup in 20 of the dogs (that's including the 4 purebreds and 4 crossbreeds). That means 1/5 of the dogs were not mixed beyond three generations. There were only 2 mega-mutts: dogs so mixed that only 1/4 of their DNA could be identified, and not even definitively. There were 17 mutts that were so mixed that less than half their DNA could be identified. The typical (median and mode) portion of a dog's DNA the test could identify was 3/4.

As for the breeds themselves, there were a total of 85 different breeds detected in the ancestry of all dogs posted. Of those, the most common breeds to appear in an ancestry report were as follows (with the number of occurrences in parentheses):

1. Labrador Retriever (19)
2. American Staffordshire Terrier (16)
3. German Shepherd Dog (15)
4. Australian Shepherd (11)
5. Boxer (10)
6. Chihuahua (9)
7. Australian Cattle Dog (8)
8. Chow Chow (8)
9. Siberian Husky (8)
10. Border Collie (7)
11. Beagle (6)
12. Great Pyrenees (6)
13. Shar-Pei (6)
14. Golden Retriever (5)
15. Miniature Poodle (5)
16. Pug (5)
17. Staffordshire Bull Terrier (5)
18. Basset Hound (4)
19. Shih Tzu (4)
20. Toy Manchester Terrier (4)
21. Weimaraner (4)
22. Dalmatian (3)
23. Miniature Schnauzer (3)
24. Pomeranian (3)
25. Rottweiler (3)
26. Russell Terrier (3)
27. White Swiss Shepherd (3)

Any breeds below that just appeared in one or two results (or not at all). Here's a word cloud of the breed results! I made it on Wordle.net by pasting in the first column of the spreadsheet - which is also how I counted the occurrence of each breed, since Wordle does that for you (after I made each breed one word). The size of the breed name indicates how frequently it came up in results.

Of course, there's no way to know how representative this sample is, but I've often wished Wisdom Panel published information like this - they've got such a huge data set, I'm sure there's some really interesting stuff to be gleaned about the genetic makeup of the dog or mutt population. So this is just a tiny piece of it!

What do you all think? Anything you find surprising or interesting? Let me know if you have any questions!

 

[miminonoko]

@doppelgank That is really cool! I guess the one thing that really surprises me is that "pug" appears 5 times in the result; I'd expect few people with dogs that have any pug in them to be doing a DNA test, since I think it's usually so visually apparent when a dog is even part pug.

I'm really curious about what we'd get if we did a DNA test on our hound. Visually, she's indisputably a tricolor Redtick (aka "American English") Coonhound, but since this breed was only very recently accepted into the AKC (2011, I think), I wonder whether a lot of Redticks really have some Bluetick and Treeing Walker ancestors not far back in their family tree.

 

[doppelgank]

@miminonoko I'm glad you think it's interesting! Further back than a generation, it's really a toss-up whether you'll see any significant breed-specific traits - this dog is 1/4 Pug, for example (Mini Poodle + "Jug," a designer mix of Jack Russell and Pug), but you wouldn't really know it except for the curled tail and the ears. At the great-grandparent level beyond that, you're less likely to see breed-specific traits than not. People don't always run the tests because they have no idea about their dog's background, but to test their suspicions, find out what else is in their dog aside from what they already know, or sometimes to test the test - four people did them on their purebreds (one of which was a Plott Hound)!

You should run one on your hound! It is harder for them to nail down breeds that are still more working than show and might have open stud books (some hounds, Catahoulas, Rat Terriers, Jack Russells) because they have greater genetic diversity, but you'd get interesting info regardless. If you tell them you suspect she's purebred American English Coonhound when you send in your sample, they'll send you charts comparing her DNA to the typical range of the breed and other closely related breeds (like Treeing Walkers), and show you where her genetic diversity falls on a spectrum of other coonhounds.

 

[miminonoko]

@doppelgank Wow, that's really interesting-- I never would have guessed that dog had any pug in it! I think I'm just used to seeing dogs that are half pug, or even 1/4 pug but for some reason still look very pug-like.

I definitely think I'm going to test my coonhound! She came from a shelter, so my opinion of her breed is based solely on her appearance (her body, head, and ear shape are completely coonhound-typical, and then her tricolor with ticking coat is what makes me narrow it down to Redtick, since Walkers aren't supposed to have that much ticking and she's way too light to be a Bluetick). I'll be very interested if she really turns out to be 3/4 TWC and 1/4 Catahoula, or something.

 

[doppelgank]

@miminonoko Awesome! You should definitely tell them to run the purebred test as American English Coonhound if you think it's remotely possible - it doesn't change how they run the test except that you'll get extra charts you might not get if you submit as mixed breed. There's a new test out (Wisdom Panel 3.0) for $85 but they also have Wisdom Panel 2.0 on Amazon for $70. The main difference is that 3.0 has a larger database of breeds (including wolf and coyote!) and screens for a mutation that influences drug absorption.

And post your results to /r/DoggyDNA when you do so we can see them, of course! You could be result #101.

 

[miminonoko]

@doppelgank I'm definitely going to get the test done, and will post there when I've got the results! As someone who's very involved with genealogy, I've done a lot of research and discussion about human DNA test results, so it'll be fun to learn more about dog DNA testing. Thank you so much for the tip; I strongly suspect that she's an American English based on the specifics of her coat color, but it also seems feasible to me that you could get a tricolor with both blue and red ticking coonhound if you mixed a Walker and a Bluetick, so who knows. There's also the fact that apparently some people who breed coonhounds intentionally cross the different types together.

I'm eager to get the results for fun, but I also just realized that it might provide some additional info. Ever since I adopted her I've been trying to track down the person who dumped her. Since Animal Control thought she was only 6 weeks, I suspected it might have been a breeder who dumped her because they thought she had parvo (I did too at first; she was so sick. It wasn't parvo though fortunately) and didn't want it to spread and/or didn't feel like taking her to the vet. I've been checking out the Craigslist postings and websites of local hunting dog breeders who are in the area near where she was found, looking for other dogs that look like her. No luck so far, but the DNA test may help me narrow it down, especially if she turns out to be a mix between two hound types.

 

[imagebeastmarkbeast]

@miminonoko Josie's results are in her list and here. Pug was a total shock! She's from a Boston Terrier rescue (although parents still unknown) so I was expecting some in there as well as another bully. You would think her face would be more smooshed for being Boston Terrier and Pug!

 

[miminonoko]

@imagebeastmarkbeast That is really cool, and very surprising to me as well after looking at that pic! I wonder if perhaps her Boston ancestor was one of the hardier ones that has a longer muzzle, and that's why her face is nice and non-smooshy. There were several Boston/pug mixes at the pug meetup we used to go to; one of them pretty much looked like a brindle pug with a non-curly tail, but the others were apparently descended from bigger, less brachycephalic Boston stock, and almost looked like your dog, except with a different ear shape.

 

[imagebeastmarkbeast]

@miminonoko Ive volunteered with the Boston rescue Josie is from. They get quite a few Boston mixes with longer noses. Even with purebred moms they get in her puppies just end up with longer muzzles. I wonder how dominant the traits are for Boston noses. If that makes sense? (I know nothing about genetics).

 

[doppelgank]

@imagebeastmarkbeast Snout length is one of those things that seems to get averaged out rather than inherited on a simple dominant/recessive - probably because there are multiple genes controlling it. Sort of like the difference between skin color vs. eye color, where kids with a light- and a dark- skinned parent tend to have medium skin (but sometimes have light or dark), whereas kids with a brown- and blue-eyed parent inherit one or the other. Josie definitely has a bit of a snubbed-nose look for 50% Am Staff - makes sense to me! She's a cutie.

 

[imagebeastmarkbeast]

@doppelgank Thanks, here is her side profile. Better nose shot

 

[aaron_boydstun]

@imagebeastmarkbeast I think I posted on your original one - but I love her face! I think Bostons are such awesome little dogs and it looks like you wound up With such a nice little mix

 

[imagebeastmarkbeast]

@aaron_boydstun Thank you! She's quite the diva

 

[onemanband2112]

@doppelgank It would be very interesting to me to see the results of these "bully breed" dogs to determine just what was crossed with pitbulls to make them so short and stocky. Most people assume it's bulldogs but I think there has been more mixing than people will admit to. Would the American Pitbull Terrier have the same DNA results as the American Staffordshire Terrier?

 

[doppelgank]

@onemanband2112 I included the link to every result on the spreadsheet, so you can check out specific the Am Staff/Staffy/Bulldog mixes if you're curious about them!

And yes! /@humbl3m1nd actually had all of her three bully mixes tested. One of hers was the one that came back as a "possible purebred" - he came back as 3/4 Am Staff and 1/4 Boxer, but the report also said it was possible he was just an Am Staff that had been bred away from the standard for enough generations. According to her, that is exactly what a pit bull (APBT) is, genetically.

Here's what Wisdom Panel says about determining pit bulls:

The term "Pit-bull" is a bit of a misnomer and does not refer to a single, recognized breed of dog, but rather to a genetically diverse group of breeds, which are associated by certain physical traits. Pit-bull-type dogs have historically been bred by combining guarding-type breeds with terriers for certain desired characteristics. As such they may retain many genetic similarities to their original breeds and other closely related breeds.

Due to the genetic diversity of this group, Mars Veterinary cannot build a DNA profile to genetically identify every dog that may be visually classified as a Pit-bull. When these types of dogs are tested with Wisdom Panel, we routinely detect various quantities of the component purebred dogs including the American Staffordshire Terrier, Boston Terrier, Bull Terrier, Staffordshire Bull Terrier, Mastiff, Bullmastiff, Boxer, Bulldog, and various other Terriers. Additionally, there are often other breeds outside of the Guard and Terrier groups identified in the mix depending on each dog’s individual ancestry.

 

[imagebeastmarkbeast]

@doppelgank

an Am Staff that had been bred away from the standard for enough generations. According to her, that is exactly what a pit bull (APBT) is, genetically.

Technically, an Am. Staff is an APBT that has been bred away from the standard for many generations. The APBT was first. But what I think /@onemanband2112 is talking about are American Bullies. Originally, they were just Am. Staff and APBT crosses, and I think Henry's results reflect that. But later many other breeds were added in, and I'd love to see Wisdom Panel results for them because a lot of breeders claim nothing was added.

This is really cool! Thanks for putting it together.

 

[doppelgank]

@imagebeastmarkbeast Ah, gotcha. The terminology for these dogs is so confusing! People use "pit bull" as both a breed and a type, and "bully" can refer to both the group and a breed within it as well... I guess it also partly reflects the fluidity and overlapping of the breeds in that group. I'm trying!

Glad you enjoyed the data.

 

[imagebeastmarkbeast]

@doppelgank Yes, it's super confusing!

 

[phillnb25]

@onemanband2112 I don't know, but you should check out /@humbl3m1nd's two results in /r/doggydna.

 

[hammer118928]

@doppelgank

1. Australian Cattle Dog (8)

That's us! Opal is one of the purebred results; I received the DNA test as a gift but had purchased her from a breeder and figured "why not"?

I think sometimes people are disappointed with their result or expected a particular breed, but I really was impressed by the accuracy.