Sep20

5 Comments

Hello out there in Genealogy Land! I have been running silent these last few months here on the blog, but continue to march yet unto that elusive tree of perfection. I have a quick item that I wanted to post today and file in Things That Make You Go, “Huh?”

When checking my matches over on MyHeritage DNA, I found one recently that is estimated at the 3rd – 5th cousin level.

DNA Match Summary
OK, I says, that’s not a bad match – although I strongly suspect that MyHeritage’s cousin-relatedness are overestimated by at least 1 or 2 levels. That would make me feel like this is really at the very best a 4th – 6th match and perhaps further. In fact, another factor feeds this assumption for me:

This match is from Norway. I am 50/50 Czech and Irish. While I understand those country-centric terms don’t accurately represent the mishmash of DNA we all carry, I have found that this match along with other matches from Norway have trees that go many generations back with clearly Norwegian names in them. (Go figure.)

So, OK, perhaps 5 or 6 generations ago someone from one of “my” countries headed up that way, or vice-versa and now I need to welcome my new Norwegian cousins and brush up on learning how to cook Kjøttkaker and Gravlaks. (Mmm, Gravlaks.) But, a couple of these Norwegian matches are in the 3rd to 5th cousin range, so you’d at least think we’d see some slightly similar locations on the map start to appear around the time our common ancestor would be. Nope.

But forget about all that – let’s look at the next thing that MyHeritage gives us for matches: Shared Ethnicities.

Now, I also understand that there is some algorithmic voodoo at play in mapping ethnicities. (By the way Algorithmic VooDoo is now my new band name.) Can one really attribute a particular snippet of DNA to a location absolutely? Eh, maybe in some cases, but overall I think they are smearing the lipstick a little broadly. In the case of this match, I found something else surprising.


Shared Ethnicities Chart

I pasted our “Shared DNA” numbers on this chart for reference – so assuming we share enough DNA to be in the 3rd – 5th cousin range, would we not also have at least one category of ethnicity that we are both a member of? I realize our total shared is only 0.4%, but even so, if they can estimate her Scandinavian ethnicity down to a 10th of a percentage, there shouldn’t really be any rounding error going on.

Yet, there is not a single ethnicity that we share.
And now I am left wondering what I should do with all of these Gravlaks?

(By the way: That Iberian % doesn’t show up at all in my 23andme results, and on AncestryDNA I have 3% Iberian in the Low Confidence Region. One of my favorite regions, doncha know.)

5 Comments

  • avatar

    Comment by David — June 25, 2020 @ 3:02 am

    Hey, it is funny. I also have this problem even after they made the matching update in 2018. Most of my 3rd-5th cousin matches (at least 2 out of 4) do not really share any ethnicities with me. Moreover, I have a Norwegian match whom I share 1.1% with (shown as 3rd-4th cousin, mind you, even closer than in your case), and we only share West Asian ethnicity (and based on their extensive trees they have nothing to do with West Asian continent, go figure what the deal of that is). It is probably an admixture to them, since they have less than 15% of it shown. I am not sure how reliable the whole matching algorithm is even now, definitely something feels off. Not only that, but some matches on FtDNA do not appear on MyHeritage either. Supposedly due to how segments are interpreted differently or missed altogether for those that transfer vs those that buy the test on MyHeritage. I used to think that ethnicity estimates are bogus, but now i am starting to lose faith in matching. These issues are simply confusing and not helpful to me.

  • avatar

    Comment by John — June 25, 2020 @ 10:57 am

    I have to go back and look at this match again and see if the algorithm changed things up over the last 3 years.

    I do agree that it is hard to lose faith in matching: I would have thought that by now with the boom in the sizes of each company’s database some of my harder to find parts of the tree would have had some serious matches.

    I have had quite a few closer known cousins test, which should really boost identifying things – but really, I have gotten nowhere with those ancestors.

    Meanwhile, on a couple of parts of the tree that I already had a full picture going back quite far in time: lots of matches. I think at least part of the whole process is luck of the draw on which distant cousins get into testing. My wife’s Nova Scotia Irish/Scottish side is bursting at the seams with matches, but my darn Tierney/McTiernans are still hiding in the bushes.

  • avatar

    Comment by Nikky — July 14, 2020 @ 10:00 pm

    Yup. On top of these chance-based surprises that we long for but rarely get, imagine calling at least 5 different customer reps and getting mixed feedback. I addressed this exact problem you described in your article when your shown ethnicities contradict pure ethnic matches of unfamiliar ethnicity. No clear explanation whatsoever. For example, I was told that your ethnicity inheritance is random and yet your matching is not affected by that. Say again? That’s a contradiction! What it supposedly means is that you will match a 100% ethnically pure individual probably as close as 2nd cousins, yet your link to the person in question remains intact. Sorry, I do not get it. Not one rep would explain this dead end mismatch to me. And that’s in addition to regions being displayed in unlikely overlap, like an Irish person showing Balkan region more than 30%, which is a riddle if you ask me. If you trust the ethnicity estimate you will likely fail. Even when you compare yourself with matches.

    Also, these matches rarely respond. And when they finally do, it feels as if our English alphabet got smaller in size.

  • avatar

    Comment by John — July 24, 2020 @ 10:07 am

    Nikky, I detect a little stress in your tone that I share with you. 😉

    Yeah, I think the ethnicities reports are still very much a toy for newbies to see in most cases now.

    I guess my optimistic take is if they keep making the toys better, perhaps at least some small percentage of people will start to become more interested and we’ll have more people to share and compare with. Fingers crossed!

  • avatar

    Comment by Isaac — August 3, 2020 @ 6:44 pm

    There are several reasons why this may happen. Some families are known to practice the so-called endogamy. Meaning they marry within a starting set of say 20 people per given generation. As a result, you may get double cousins on some lines. Because you may be related to them in more than one way. This may exaggerate the relationship closeness, which shows a percentage of shared dna larger than what may be normally expected from this type of relationship. To see how this works, suppose your brother married your wife’s sister. Your children would have some common segments split into more segments while the total shared dna may not decrease by a lot.

    Norway and Ireland are close geographically speaking. If one of your Norwegian matches had an Irish ancestor common to you both 7-8 generations ago, or you had a Norwegian ancestor that long ago common to the match, it may be due to the common ancestor being possibly very endogamous. Some parts of Norway are so interrelated that matches from those areas tend to be 5th-6th cousins two or even three times. Similarly, the Norwegian ethnicity would probably not show up in your estimate if your match had a remote endogamous Irish ancestor. Every country displayed endogamy at some point in time in certain areas, usually they happen in rural communities.

    Finally, a NPE (non-paternal events) may exist in your tree or theirs. This means that genetic trees may be different from paper trail ones. This happens when somewhere in your trees there is a break of some sort. It may be paternal/maternal infidelity, secret baby adoption, unintentional baby switch at birth, among other possibilities. And it is very difficult to trace these mistakes or breaks that happened so far back in time. Research shows that every tree has a NPE somewhere. Some relatively close in time, some hundreds of years back.

    There is no rule set in stone, so personal research is probably the best bet to solve these inconsistencies.

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