Some people eat, sleep and chew gum, I do genealogy and write...

Tuesday, January 21, 2014

Can DNA Testing Help You Find Your Ancestors? Part Two

Where does DNA testing fit into the spectrum of genealogy research? The upcoming RootsTech 2014 has 122 class sessions on the schedule. There are nine scheduled classes focused on or mentioning DNA as part of genealogy. But where does DNA testing actually fit into the genealogical research process? Let's suppose that you are an absolute beginner in genealogy. You pay your money to the DNA testing company and send in a swab or whatever for DNA testing. How much of your family history will you know once you have received back the results of the testing? How will what you learn help you find you ancestors?

Let me pose another hypothetical situation. Let's assume that I have been doing genealogical research for a long time and have accumulated a huge, completely documented, completely sourced pedigree back seven or eight generations. I have been diligent and every line goes back to the sixth generation with only a very few missing ancestors in the seventh generation. In looking over my pedigree, I see that the dates of the missing ancestors are in the 1700s, in fact, many of this generation were born in the early 1700s. I note that I have traced every line to the country of origin out side of the Americas. On a whim, I decide to do a DNA test and send in the required swab to a company that advertises that it will provide me with a breakdown of my ethnic percentages. I get back the results and they show that I have possible Native American ancestry. Since I have already documented all of my ancestors to places outside of the American continents, how would this be possible? Or was the test simply wrong?

Am I to suppose that one or more of my ancestors was actually a Native American based solely on this test? Do I go back to my research and try and determine which line could possibly have been Native American? What is the relationship between traditional or online family history research and DNA testing?

Now let's modify the hypothetical. I have done my research and I have documented my pedigree but I get back to the 7th generation and I find that my remote ancestor, John Smith, is one of several Smith's in the same town. In working through each of them, I find that there is one other Smith, William Smith, who might be a relative. My research has been unable to prove which of the other Smiths in that town at that time are related, if any. I do find that another researcher has documented his line back to William, but has also not found out whether our two lines are connected. We decide to do a DNA test. I recruit several of my cousins and the other researcher recruits several of his cousins and we all submit for DNA testing. The test results show that William Smith and John Smith are likely related.

What do I now do with the information I have obtained? That is the real question in all of the hypothetical examples or any other examples that could be given. In my last hypothetical, we now have two very capable genealogists who believe they have a common ancestor. Even with a demonstrable relationship, there may be no further records enabling the researchers to extend the family line to the next generation. Perhaps establishing the relationship could not be done in any other way, but how helpful are the results? Even if you were to posit another hypothetical with the facts that would allow the two researchers to extend the now common line one more generation, the DNA testing alone will never provide that information.

Even if we were to suppose that I had been unable to establish a connection between myself and the hypothetical John Smith and did the DNA test as a guess, the fact that John Smith and William Smith are related and that I am a possible descendant of John Smith, does not necessarily help me fill in the gaps in my research.

In these cases, I am ignoring the motivational aspect of DNA testing. If I do a DNA test and the company tells me I have such and such a percentage of probability of relationship to royalty, where does that get me other than spur me on to do the genealogical research necessary to establish the claimed ancestry? Is it enough to know that a certain percentage of my ancestors came from Scandinavia or do I still have to do the research to establish that connection? The answer to that question is at the heart of the DNA issue.


  1. Sure, one can posit situations where DNA evidence isn't helpful. But you wouldn't have any difficulty developing situations where additional conventional genealogical evidence isn't helpful either. Nore to the point how do you know the documentary evidence is giving you the truth? As Helen Leary wrote a long tome ago “Science and the law are in agreement: there is only one way to prove kinships beyond reasonable doubt — DNA” Find that on the BCG website.

    1. It would be nice if that were always possible. But without the paper research, DNA has limited application to genealogical research. it may be interesting to know for sure who your parents are, but how far back can that go without researching first? That also assumes that your relatives will cooperate in adding their DNA to the study assuming they will talk to you in the first place.

  2. I think DNA research applications for genealogical research are directly related and equivalent to fingerprinting. [Even identical twins (who share their DNA) do not have identical fingerprints.] It is all a matter of assigning a degree of confidence. [Since the early 20th century, fingerprint detection and analysis has been one of the most common and important forms of crime scene forensic investigation. More crimes have been solved with fingerprint evidence than for any other reason.] Dermatoglyphics is the science by which we can [determine whether these impressions could have come from the same individual. The flexibility of friction ridge skin means that no two finger or palm prints are ever exactly alike in every detail; even two impressions recorded immediately after each other from the same hand may be slightly different.] So if we want an ancestry background check, we should gather all the family fingerprints and put them all together and compare them, both for the father's side and the mother's side. Then, with the same degree of confidence of determining DNA "matches", we should be able to directly trace back all our ancestry. Yes, No, Maybe? Biometric [identification utilizing a physical attribute that is unique to every human include iris recognition, the use of dental records in forensic dentistry, the tongue and DNA profiling, also known as genetic fingerprinting.] The problem I have with all of this is the logic behind the big story, because I am told that DNA is the "engine" that creates all of this unique identification in every human being. That, however, says to me, that over generations of time, every person, father, son, mother daughter, brother, sister, relative, each had a former DNA "engine" creator that produced another individual that in and of itself, starts off life with its own altered DNA "record" (it must be so to produce individuality); this then produces other altered DNA "records" in its posterity. So the issue is not with the continuous replication process which is so nicely discussed exactingly in family history DNA related venues, it is with the very fact that everyone who is a human being is individually genetically altered. And unless you can trace genealogy created patterns in fingerprints, iris recognition, or some other form of biometric identification, you certainly cannot with confidence, trace back with any form of certainty, unique DNA profiling, which ever so minutely changes from one person to another, over all generations of time. This is of course my own personal opinion on the matter, fortified by my own experience of seeing enthusiastic DNA potential "matches" contradicted by written record sources.

  3. As you point out, James, DNA must go hand-in-hand with paper research. But I think you haven't addressed an important point when it comes to DNA and genealogical research: Both yDNA and mtDNA have the power to falsify a "perfect" genealogy based on an impeccable based on paper research. The pursuit of negative findings, too, is a critical part of doing good genealogy.