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Decoding the canine genome (one dog at a time)

January 20, 2009 |  8:26 pm

The world's first Toy Fox York-tzupinscher?

Our mystery mutt, Django, just became a little less mysterious.

We told you recently that we'd taken the plunge into the murky, scientific waters of mixed-breed DNA testing. We went with the Wisdom Panel, which uses a complicated-sounding computer algorithm to detect "breed signatures" from 157 dog breeds in a small blood sample. Sounds like you'd have to have a PhD to understand it, but the results are broken down into a relatively simple report that looks something like this.

We received Django's analysis today; you could have knocked us over with a feather when we opened them!

The results?  Our little bundle of terrier energy is, in fact, mostly terrier -- no surprise there.

But the type of terrier?  Now that was interesting.

Django's DNA analysis

The Toy Fox Terrier is listed as the only "Significant Breed" in Django's heritage, meaning it accounts for at least half of his DNA.  And he definitely exhibits some of the personality traits said to go with the breed -- "agile, energetic and intelligent" fits him to a T, and "tendency to bark" definitely struck a chord. But appearance?

"With a short, glossy coat that is predominantly white, the appearance is elegant, balanced and aristocratic," says the Toy Fox's breed standard.

Hmmm.  Django is brown with some black shading (no white save for a tiny, blink-and-you'll-miss-it strip on his chest); has a wiry, broken coat; and, although we have nothing but admiration for the little guy, "aristocratic" is definitely a stretch.

An "Intermediate Breed" would have accounted for at least 25% -- but none was detected. As for those little icons listed as "Minor Breeds," they account for 12.5% each (but the asterisk next to each notes that they were "detected at low confidence").

Among them are the Yorkshire Terrier (makes sense), the Affenpinscher (makes a little bit of sense, if you squint), and the Shih Tzu (we're still reeling about that one).

A perusal of the Wisdom Panel's FAQ section makes it quite clear that the "Say what?" elements of Django's results are not uncommon. "My dog looks nothing like the breeds detected in the WISDOM Panel™ MX analysis. Can you explain how this can happen?" reads one FAQ. The answer:

Many parts of the canine genome are likely to be unobservable or hidden with regard to trait determination. This can happen for any number of trait-determining genes. Simply put, a mixed-breed dog could be a mix of 3 or 4 breeds but have few traits evident from one or more of these breeds.

There are two good examples of how this can happen. The first is eye color in humans. Brown is dominant over blue and green, and yet, a brown-eyed mother can have a green-eyed son if the dominant brown eye color variant is not passed on. The second, and perhaps best, illustration of the surprising effects you may see when mixing breeds is to study some designer dogs (e.g puggles, cocker-poos, etc.), which are a custom combination of two different pure breeds. Often these dogs will look quite different to the founder breeds because they are a mixture of two very different sets of genetic backgrounds. Equally many dog breeds still contain a variety of genetic variants for specific trait genes, especially coat color, size and coat type. For example, there are many different forms of Schnauzers such as miniature, standard and giant, and there are many different coat colors and coat types found in the Dachshund breed such as wire-, smooth- and long-haired. Dogs can be many different colors and yet are still classified as the same breed.

Who knew our humble little mutt would turn out to be such a science lesson?

Related:
Adventures in dog-related science
Guess that mutt!
My big N-O to dog DNA tests

-- Lindsay Barnett

Photo: Robert Black

Screenshot of DNA analysis report is courtesy of Mars Veterinary.

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