Home Page Forums Darwin’s Ark Change in Results

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    kristen johnson 2

    I know that the breed results were supposed to change as new breeds got added to the database. My dog, Dexter, had breeds removed from his results though. I’m just wondering why that is. He was a mix of Australian Cattle Dog, Jack Russell Terrier, Wired Hair Fox Terrier, and Boston Terrier. Now his results show he’s a first generation mix of an Australian Cattle Dog and a Jack Russell Terrier, with 2. 3% Yorkshire Terrier in there. I don’t doubt the results a bit because he has many behavioral characteristics of a JRT for sure, but I’m curious what caused a change that would remove breeds and greatly increase the JRT. My other dog, Luna, also had some changes. I saw the addition of the American Pit Bull Terrier and knew those weren’t in the database previously so that made sense, but I saw she also now had JRT as well. I thought that breed was already in the results because Dexter had some in him previously but maybe I’m remembering that wrong…….


    bre anne harris

    My Dexter changed as well. He was 85% Golden Retriever and 15% unknown and now it shows as 99.9% Golden Retriever. I read up on the v2 updates, but I don’t see anything that would explain that change, but I may be missing something.


    kathleen morrill

    Hi Kristen & Bre Anne,

    The primary reason for breed results changing were changes to the algorithm we used. A couple other aspects of constructing the new breed reference panel might further explain the new results for Dexter & Dexter:

    First, the individual 12 dogs sampled for each breed have changed. Previously, we used publicly available array data for these breeds, for which the genetic data is sparser (~200,000 locations on the DNA) than the data we gain through sequencing (millions of markers). Wherever possible, we substituted in dogs of the same breed that had deeper sequence data available.

    Second, the number of genetic markers has increased. When we were limited by the publicly available genotyping data, we previously examined under 200,000 markers for breed ancestry. Now, we have identified over 600,000 informative markers that help distinguish between 101 breeds.

    When I take a closer look at Kristen’s Dexter and the old results, I do see that the most confident breed portions came from JRT and ACD (followed by Wire Fox Terrier). I suspect that the non-JRT Terriers — including the current 2% Yorkshire Terrier call — are misidentified portions of Jack Russell Terrier. The Jack Russell Terrier is an especially challenging breed for both the old and new algorithm, because, as a breed, JRTs are exceptionally genetically diverse!

    For Bre Anne’s Dexter, these results were certainly affected by the substitutions in the panel. Golden Retriever is a breed with a ton of deep-sequenced data available, so we were able to prioritize representing more diversity within the Golden Retriever breed panel.

    Please let me know if I can clarify more with the new results!




    kristen johnson 2

    Thank you Kathleen! I appreciate you taking the time to explain. I really am just super curious about the whole thing. I’m not disagreeing or questioning……just intrigued. I think that makes sense with the other terriers being misidentified. But can I ask about my Luna’s changes. Maybe the English Shepherd was misrepresented as German Shepherd? She did have 2.5% Chow Chow but that’s gone……I don’t see any breeds that are similar there. I know the American Pitbull Terrier is a new breed that was added, was the Brittany as well? Also her percentages of most things increased, like she was 10.5% Australian Shepherd and now she’s 15.1%. What causes that to happen? Thank you again for taking the time to explain, I just love learning all I can about this study.


    bre anne harris

    Thank you, Kathleen. My husband has always said Dexter wasn’t purebred, now I can prove him wrong with science. A huge thank you for all the hard work you all do there at Darwin’s. We greatly appreciate you!

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