Twins get 'mystifying' DNA ancestry test results (Marketplace)

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CBC Marketplace investigates the science and marketing behind popular DNA ancestry kits. Host Charlsie Agro and her identical twin sister Carly test five top brands. Find out why ancestry test kits are not as accurate as you might think. To read more:

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36 Comments on “Twins get 'mystifying' DNA ancestry test results (Marketplace)”

  1. I got in a youtube discussion over this a while back. Ancestry has done many good videos, but they put up one that claimed that getting the testing done would open up your ancestry story; they then started into the subject's ancestry, with documents and such and never again said anything about how getting testing done would improve what was likely pulled together by a professional genealogist. I questioned it, and got back an answer from the official source saying that "testing is a valuable part of genealogical results". In truth, mtDNA and Y-Chromosome testing can definitely help illuminate areas in the tree under very specific circumstances; I had a very surprising "twist" in my tree by this avenue. This autosomal testing (the common sort that is done in job lots by these companies) says very little about your specific ancestry. What it does, which is valuable, is to put you in touch with cousins you didn't know existed, and they can add their research, knowledge and photos to yours.

  2. Modern technology is amazing, until it's proven wrong and that we know didly. Given the migration and interbreeding in human history, how can they say Italian/French/German, Nigerian/Kenyan/Moroccan, Chinese/Mongolian/Korean?!?! Britain, Iberia and North Africa were all part of the Roman Empire. Genghis Khan conquered from east Asia to Europe. DNAs were spread all along the way and mixed. Most people are mongrels.

  3. problem is not 2 tests giving different results, because they have different populations in their database, problem is 2 twins having different results in the same company (it happened), there are version differences though too…my tests are variable but in the same area and very cohernt on a continent area. being adopted , it was useful to know

  4. From my guess as a machine learning newbie, they probably used an algorithm called "k-means clustering", basically try to find the cluster of different ancestry, and mark the center of cluster.

    If you test on your DNA data, you are compared to the distances between your DNA data to the center of all clusters to get the rough %.

    The problem of DNA is, it is very very huge, and even bigger with the number of ppl in database, so they cut down and analyse only certain features of DNA that are trainable with their computer.

    Obviously, if we use different features, you will get variations of mathematical model. Different companies have different models, so it is possible that you will get different results. But for the identical twin? It could be that they don't have exactly identical DNA. I'm not a biologist, correct me if I'm wrong.

  5. Pretty sure health insurance companies now have their DNA results. Hope the results didn't identify any tendencies toward serious diseases. If so, expect higher premiums sometime soon.

  6. I took one through Ancestry.com because I already have an account with them, and other members of my family also have accounts and have done their DNA tests. Based on what I know from my dad and my aunt's extensive research into our family tree (before there even WAS an Ancestry.com) my results matched up pretty well with what I expected to find. I did have to do most of the research on my mom's side of the family myself because her family are not as into where they came from. Even still, the results I got matched with the cursory research I did, even if it was in just a broad generalized way.

  7. Even though they are identical twins they do not even look identical. So why would their dna be identical. The egg split and there is a slight possibility that they do not get identical dna. After all they are two separate people. They are not exact replicas of each other. One may have a mole somewhere and the other a birthmark. But they are still identical.

  8. Though DNA test advertising is deceiving, the piece was also deceptive, concentrating on what I call "cute" genealogy (ethnicity estimates).

    I think it unfairly implies that ALL DNA testing is "fuzzy', when the part that identifies matches is extremely accurate.

    It may tell me that my sister and I have different ethnicities, but it absolutely confirms that we are siblings.

    The piece also didn't make much of the fact that AncestryDNA was the most consistent in presenting the twin's estimated ethnicity.

    Also, it neglected to point out that the smaller the percentage of estimated ethnicity, the wider the discrepancies.

    It did make me wonder if the 'algorithms' these venues use actually include some human analysis. If it does, that would explain why two sets of raw data gave different results, if a different person reviewed each set.

    Since my paper ancestry is all Sicilian, I don't pay much attention to the ethnicity estimates, though mine is 100% 'Italian', so there's nothing for me to question! 🙂

  9. Missing small family history however, I have enough information to know who I'm related to. Grew up with at least 300 and more family members on both maternal AND paternal. TALK TO YOUR PEOPLE. Exchanges of the stories are FAR MORE VALUABLE. Just don't loan each other money……?

  10. Do not blame the industry…. they are clearly for profit anyway! Blame yourself as a consumer for not reading the “fine print” or for assuming that a 0.3 percent of something means you are that…. Anyway the big percentages seem to be kind of close enough

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