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  • Olivier Felber

DNA Tests: Humbug or the Future of Genealogy?

Genetic testing or DNA tests are controversial. On the one hand, providers like MyHeritage promise “to pinpoint where in the world your ancestors came from.”[1] On the other hand, experts such as molecular biologist Martin Moder stress that it is impossible to see “where DNA was walking around in the past.” One can only determine “with what probability which gene regions occur where today.”[2] There are other reasons why DNA tests are criticized: For one, sensitive information such as genetic diseases can be discovered. Also, there are concerns regarding the providers in terms of data protection, closeness to Google, or handing out DNA profiles to the FBI.[3] With a DNA test, unpleasant surprises might come up, such as the discovery that one’s supposed parents are not actually one’s biological parents.


This blog post describes what you can expect from a DNA test. It focuses on the ethnicity estimate and the listing of relatives. The results are also viewed critically. Concluding, the practical usage of DNA tests will be evaluated as a whole: Will DNA tests replace research in archives? Are they a useful addition to traditional genealogy? Or are they of no use?


There will be no introduction to DNA and the functioning of DNA tests. Information on this can be found elsewhere.[4]



Direct Hit or Horoscope? The Ethnicity Estimates

The main reason for people taking a DNA test might be the breakdown of the DNA into the different regions of the world. One’s ancestry is portrayed in an easy and comprehensible manner. The results suggest a clear answer to the question of where one comes from.


I tested my parents’, my two grandmothers’, and my own DNA at 23andMe.[5] Our ancestors are almost completely traced back to the 18th century. All of them were from German-speaking Switzerland. Most family names are mentioned in Switzerland for an even longer time. Therefore, I expected to see that reflected in the DNA test.


The geographical breakdown of 23andMe pretty much mirrors my own family research. According to the results, all tested family members have Northwestern European DNA, ranging from 96.8 % to 100 %. Most of it falls under “French and German”, which includes Switzerland. As an example, you can see the ethnicity estimate of my paternal grandmother.


The results of my paternal grandmother on 23andMe are not surprising: Most of her DNA, 98.1 %, is “French and German”. Picture: 23andMe.


To a lesser degree, other European areas are shown. For my paternal grandmother, 1.6 % Scandinavian origins are shown, for my mother and me, it lists 2.3 % or 2.6 % respectively of Italian DNA. Interestingly, all of us, except my maternal grandmother, have North African DNA. However, these results only range from 0.2 % to 0.6 %.


At 23andMe, you can pick the reliability of the results yourself. As a standard, it is set to “speculative”, which only offers confidence of 50 %. You can change that value up to 90 %, however, not much changed about the results of my family in this new setting; the regions only get a bit less specific. The Scandinavian and North African DNA disappear completely. From time to time, the algorithms are adapted, which is why the results of my family have changed several times.


Besides that, 23andMe offers to show country-specific regions from which ancestors might have come from. These regions seem to be only partially reliable. While they do show all the cantons for my family members where ancestry is proven, the results also list many other cantons and regions abroad to which there is no known connection yet.


Later, I have uploaded the DNA data to MyHeritage[6], another provider of DNA tests. While the estimates of 23andMe correspond pretty much exactly with the documented ancestry, the results of MyHeritage are less accurate.


For my parents and my maternal grandmother, MyHeritage also mainly shows North and West European ancestry, to which Switzerland belongs. The numbers range from 70.4 % to 78.1 %. In my case, this DNA only amounts to 50.0 % and my paternal grandmother supposedly has no DNA from there, as you can see below. According to the results, she would be 31.8 % Scandinavian, 22.2 % Iberian, 20.8 % Irish, Scottish, and Welsh, 14.5 % Greek and South Italian, 6.7 % Balkan, as well as 4.0 % English. Moreover, my maternal grandmother would be 6.5 % Finnish, my father 12.4 % Balkan, and I 30.1 % Greek and South Italian. This does not correspond to what I have found out about our ancestry.


This is the ethnicity estimate of my paternal grandmother on MyHeritage. Almost all regions in Europe are shown. Notably, the category which includes Switzerland is absent. Picture: MyHeritage.


What also stands out is the fact that the percentages on MyHeritage do not add up regarding inheritance. My father and mother, for example, do not show Iberian DNA in their results, yet I still supposedly have 2.8 % of it. It is also unclear how my father can be 70.4 % North and Western European should his mother have no such DNA.


MyHeritage also shows “genetic groups”, to which the tested person might belong. These groups are sometimes much broader than the regions on 23andMe. For example, Central Switzerland covers the cantons Obwalden, Lucerne, Nidwalden, and wrongly Fribourg. The group assignment on MyHeritage seems to be more reliable for my family than the ones on 23andMe, but that might only be because of the broader defined groups.



Thousands of Cousins: The Listing of Relatives

DNA tests can not only be used for ethnicity estimates, but also for the tracing of relatives. To do that, it is necessary that relatives have also taken a DNA test. The choice of the test provider defines the rate of success, since different companies are more popular in different regions.


It also needs a certain amount of shared DNA to decide the kinship. On MyHeritage, I have about 3’000 relatives, as you can see below. But only a few of them are close relatives. A good tool for calculating relationships based on shared DNA is DNA Painter.[7] A common DNA of just 0.5 %, for example, is less informative as it could be from a third cousin as well as from an eighth cousin. With 1 % shared DNA, kinship can be anything from a second cousin to a fifth cousin. The more DNA you share, the easier it is to determine the exact relationship.


MyHeritage lists around 3’000 relatives of mine, of which most are only distantly related. Picture: MyHeritage.


On 23andMe, where the majority of clients come from the US, my family only has one relative with more than 1 % shared DNA. The others are all more distantly related. For genealogy, this is not really useful. On MyHeritage, I had much more success since it is more popular among Europeans and the Swiss. I have 16 relatives who share between 1 % and 2.4 % DNA with me. My maternal grandmother has 18 relatives with more than 1 % shared DNA, the closest relative shares 8.1 % DNA with her. My paternal grandmother only has three closer relatives, of which one shares 9.5 % DNA with her. From time to time, new closely related persons appear on MyHeritage.


The list of reasons why one might take a DNA test is large. Some only want to have their ethnicity visualized and do not care about their family history. Therefore, it is not guaranteed that one can establish contact with every relative. Many will probably not see messages at all as they are not checking their profile anymore.


The listing of relatives is especially important if one is searching for relatives they know nothing or only a little about. That is the case for adopted children who are looking for their biological parents. I once was in contact with a woman who was looking for her biological mother. She only knew her name and her approximate age. With her relatives on MyHeritage and the research in a family chronic, it was possible to find her mother. Therefore, DNA tests offer a good, sometimes maybe even the only start for adopted children who are looking for their biological parents.



Neanderthal DNA and Haplogroups: What One Can Learn as Well

Besides ethnicity estimates and listing of relatives, there is also other information that you receive by taking a DNA test. On 23andMe, for example, you see the haplogroup of the mitochondrial DNA (mtDNA) and, only in the case of men, the haplogroup of the Y chromosome (Y-DNA).


In short: Y-DNA is passed from the father to his sons and is only found in men. mtDNA is passed from the mother to all her children. With these two haplogroups, you can theoretically research the straight male and straight female line of ancestors.


The amount of Neanderthal DNA is also identified by 23andMe and compared to the percentages of other clients. Through that, I have learned that I have more DNA from Neanderthals than 80 % of the clients, as the picture below shows. For classical genealogy, this kind of information is usually less important.


It is interesting to see how much Neanderthal DNA you have. However, you cannot do anything with that knowledge. Picture: 23andMe.



Conclusion

Can DNA tests replace traditional genealogy? Not really, because the ethnicity estimates are not always equally reliable. Additionally, these results are rather vague. The category “French and German”, for example, does not specify where exactly the ancestors lived. Also, you do not learn about the lives of your ancestors. One can only learn more about their ancestors like their names, places of residence, professions, and life stories by researching written documents.


However, a DNA test can roughly indicate in which direction your family research might lead. Especially people with a geographically diverse or completely unknown ancestry can get a glimpse into their past. Depending on the provider, the quality of the results varies a lot. For my family, 23andMe seems to be pretty reliable, MyHeritage not so much. Still, the results should always be viewed with a certain caution.


DNA tests can further help in establishing contact with related researchers, which can lead to an enriching exchange. When looking for Swiss relatives, MyHeritage is more useful than 23andMe. Because relatives are not always genealogists, it is not guaranteed that they are interested in establishing contact.


People with concerns regarding DNA tests do not have to worry: You can usually do your family research without one. Under certain circumstances, a DNA test might be helpful, especially for finding relatives. In cases of unknown parents, which is the case for adopted children, a DNA test might be necessary or at least recommendable.


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[1] https://www.myheritage.com/dna (access on 30 November 2021).

[2] MyHeritage, AncestryDNA, 23andMe & Co. Ist Ahnenforschung mit Gentests-to-go zuverlässig? Version of 30 September 2019. In: MDR Wissen. https://www.mdr.de/wissen/podcast/challenge/ahnenforschung-vorfahren-gentest100.html (access on 30 November 2021).

[3] Pettinger, Bianca: Online-DNA-Tests: Ein wahrer Datenschutz-Albtraum. Version of 19 February 2020. In: Dr. Datenschutz. https://www.dr-datenschutz.de/online-dna-tests-ein-wahrer-datenschutz-albtraum/ (access on 30 November 2021).

[4] For example (in German): Scholz, Roman C.: DNA – Genealogie. Gentests als Hilfsmittel der Ahnenforschung. In: Familienforschung Schweiz. Jahrbuch 41 (2014). p. 223–232. https://dx.doi.org/10.5169/seals-698123 (access on 30 November 2021).

[5] https://www.23andme.com/ (access on 30 November 2021).

[6] https://www.myheritage.ch/ (access on 30 November 2021).

[7] https://dnapainter.com/tools/sharedcmv4 (access on 30 November 2021).

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