Family Lines

Is A DNA Test Right For You (Part 1)

This is the very first blog post I’m doing for this website. I thought hard about what topic I should start with. Should it be something bland and broad like “How To Find Your Ancestors” or a bit more focused like “Looking at Census Returns”?

Or should I start with something complex, a subject with an underlying theme of serious science, something at times even controversial.

Well, you can see what I picked!

First a caveat or two. I’m NOT an expert. I think of myself as someone rising from the ranks of a genealogical hobbyist, striving toward  a professional outlook and expertise. I’m not there yet, but I’m working at it.

Therefore, think of my views on this subject as a work in progress. I’ll learn more about how DNA testing works and its implications for individuals, families, and society as a whole. I am likely to refine and maybe even change my advice (you should see the changes that the testing companies make themselves!). Meanwhile, I’ll share with you what I’ve learned so far.

What Can Be Gained from a Standard “Consumer” DNA Test?

By a consumer test, I mean one of the products you see advertised on television. They essentially offer information on your inherited relationships, connecting you to other people who have also been tested. As a result of your test, you might learn about or confirm your position within a specific family tree. You might discover or, again, confirm your ethnic background.  Some companies, 23 And Me being one, even offer a modicum of genetic counselling, telling you what syndromes or diseases you may be prone to. The largest testing company, the one  connected to the genealogy website,, just recently began to offer a medical component to its testing for those desiring it.

In other words, if you purchase one of these tests and submit your sample to a lab, you will be put on a potentially vast genetic map; you will have your own personal and unique address within the neighbourhood of the human race.

But what will you personally gain from such a test?

  • A list of people to whom you are related, your DNA matches. They can be easily called up when you log in to your DNA test provider’s website. They may be in your immediate family or among your aunts and uncles (depending on whether anyone that closely related to you has also submitted a DNA sample with that company). You will find that your DNA matches are mostly cousins, varying from first cousins to those of varying degrees of the term “distant.” The edge of relatedness seems to end around eighth cousin. An eighth cousin is someone with whom you share a great-great-great-great-great-great-great grandparent. That shows you how far the tests can take you with a reasonable degree of accuracy. Of course, the more closely related you are to someone, the more accurate the analysis of “relatedness” is. So far, I have no quibbles with my test’s accuracy in this regard. I either know about – or am confident I can discover a link to – the connections I share with “near” relatives (let say up to fourth cousin or so). OR  the ancestral links to my DNA matches go so far back they are essentially meaningless at my current stage of family research (though in some cases that could change). 
  • An analysis by the testing company for each match indicating HOW MUCH DNA you share (in measurable bits called “centimorgans” – don’t ask me what they are!). You are also given a rough degree of how closely you are related to any particular match – a guideline only, but I have found the analysis to be amazingly accurate in regards to matches whom I actually know (my mother, my two children, five or six first or second cousins, and at least two third cousins).
  • Quite often you will be able to gain access to the online family trees of the relatives you discover, depending on whether (a) they HAVE such a family tree – it’s not a requirement for the testing; and (b) they wish the tree to be available to their DNA matches. Perusing the family trees of your DNA matches almost certainly will lead you to genealogical information about your family – perhaps just a little, but perhaps a great deal.
  • Your list of DNA matches is divided into very useful segments called “Shared Matches.” These are people who not only share DNA with you; they also share DNA with other people you’ve been matched with.  It works like this: Say you have a DNA match named Elmer (people often use their real names, but often they don’t). The company you’ve tested with says that the amount of DNA you share with Elmer means that he is quite likely to be your first or second cousin. Pretty close kinship. But you’ve never heard of Elmer, and he doesn’t have a family tree online that you can look at. You ask your mother and she’s never heard of him either. Yet you also see that Elmer shares DNA with your son and also with a first cousin whom you DO know on your late father’s side (which may be why your mum doesn’t know Elmer – he’s not HER cousin). Through these shared matches, you can be confident that Elmer IS related to you and to your father. At this point,  you just don’t know how exactly. In my case, I have quite a cluster of DNA matches whom I’ve figured out share a connection to one of my great-great grandmothers named Theresa Haug. Theresa, a formidable hausfrauen who emigrated from Germany in the mid-19th century, gave birth to 13 children. In partnership with her husband, she carved a farm out of the Michigan wilderness. Some of these shared matches, like me, are among Theresa’s direct descendents. But most are descendents of her siblings or even her cousins. At first I established the validity of the connection because I could see shared matches that I KNEW were related to me through Theresa. Then I began to see  the surname “Haug” or “Hough” or “Hogg” in the family trees of other shared matches who have such trees and allow such access. Eventually, I noted a whole cluster of people who shared DNA with those of us with this ancestry. I don’t need to have access to their trees to know, with reasonable certainty, that we descend from a family with the surname of Haug, who lived in or around Wurtemberg, and who had more than one (likely several) members immigrate to the United States in the 19th century.
  • You will likely get some information on your ethnicity through a commercial DNA test, which may or may not confirm what you already knew from your family history. But, though this is the most heavily promoted product of DNA testing, it also tends to be its most unreliable component. The testing companies continually say they are expanding and refining the repositories of DNA they rely upon for ethnicity analysis. They also say they continue to fine-tune their measurements. But the resulting summaries should still be taken with a grain of salt. For example, the ethnic analysis of my mother’s DNA confirmed pretty much what she was told – that she is of entirely Eastern European extraction (in her case Polish). Since half of my genetic makeup comes from my mother, that means that I should be half Eastern European, barring any similar descent from my father as well. However, I am considered to be slightly less than that – my results are 44% Eastern European after the last review of my sample (the third since I first submitted it three years ago). There’s a small discrepancy which can’t be accounted for – except by admitting that the analysis of either my mother or me (or both of us) varies somewhat from reality. Looking at my analysis, I don’t quibble much with the components; they pretty much coincide with what I know about my ancestors. Still, the proportions seem a bit off. And many others who have been tested report results that are way off.
  • Not everything you gain from the test will be necessarily positive or even neutral. If you have any skeletons in your ancestral closet, don’t be surprised if they come clattering out. [And, of course, what you consider to be a skeleton might be a fascinating, quirky factoid to someone else – even to your sibling or to one of your close cousins.]

In my next post, I’ll be writing about a pretty common example of a “skeleton in the closet” scenario in my own family. And here’s a hint: It almost doesn’t matter if you want to protect a family secret by NOT submitting DNA for an ancestry test. Chances are good that enough of those darn cousins of yours will have been tested, and the cat could well jump out of the bag anyway (to mix my metaphors between cats and skeletons, closets and bags).

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