These days people are bombarded with a plethora of ads from various DNA labs, each promising to reveal all the information anyone ever wanted to know about their ancestral origins. And while adding DNA analysis to our genealogical research is quite helpful, we should remember that it is only one tool among many used to uncover our family history. DNA results should be always taken with a grain of salt (and sometimes with outright suspicion), both because of the unreliability of some labs and also because other labs have limited databases in the comparison testing. (Here is a good article to read about interpreting DNA results: Ancestry DNA Tests: How Accurate Are They?)
Even when evaluating the results from a reliable lab, one has to keep in mind that DNA is testing for physical genetic markers found in our family line, not for national origins. Simply because one may have DNA that is predominantly from one geographical area does not necessarily mean that our immigrant ancestors were from that region. For example, when my wife had her DNA tested, we all expected it to reveal a very significant amount German (central European) DNA because we have substantial records of a number of her ancestors having immigrated to America directly from Bavaria in the 19th century. But instead, her DNA revealed very little German but a great deal of Scandinavian DNA. To date we have found no ancestor from Scandinavia in her line, but it would seem to indicate that long ago many of her ancestors immigrated from Scandinavia to Bavaria where they remained for some time before coming to these shores. The DNA remained Scandinavian, but her immigrant ancestors were culturally and linguistically German.
Most people who submit their DNA to a testing lab are primarily interested in learning more about their ethnicity. Those who wish to learn more about their family tree may do so by exploring the trees of others who also have had the test and who share matching DNA with them. The standard (autosomal) DNA tests can usually detect matches who share a common ancestor back five or six generations. Those seeking ancestral information farther back can utilize Y-DNA tests which are capable of identifying matches in the paternal (male) line back hundreds of years.
For people interested more in learning “country of origin,” one must keep in mind that simply because one hails from a given national region does not mean that one’s DNA will necessarily reflect that heritage. My family has been in America now for roughly 300 years, but we do not have “American” DNA. The same appears likely with our ancestors. Much information in the Craton line leads us to conclude that our immigrant ancestor came to these shores from Scotland (some say from Ireland), which would imply that we should have a great deal of Scottish DNA. But my own tests show a predominance of English DNA in my line, and in fact there appears to be more Welsh even than Scottish in my ancestry. But that does not disprove the possibility that my ancestors may have immigrated from, or even lived for a great while in, Scotland.
I personally have had DNA tests performed by five different labs, all with good reputations. Two of these labs even retested my DNA sample after they significantly expanded their database. In my case, all five labs give generally consistent results, differing primarily only in the percentages ascribed to various regions. Only one major inconsistency was noted between the labs: Two of the five labs indicated a notable percentage of Iberian DNA, but the other three showed none whatever. Of the two that did, one retested the sample after expanding their database, and the subsequent test showed no Iberian influence. The one remaining lab, though noted for its reliability, refused to release the raw data from my tests (citing privacy and security issues), and as a result I remain somewhat suspicious of its findings. Otherwise it, and the other four, all point to my ancestors having all originated in the same geographical regions to which our paper trail has led: Great Britain, Ireland, and northwest Europe (Netherlands). The image below is a compilation of data from all five labs and is believed to be the most accurate representation of my own DNA:
Paternal haplogroup R-FGC11134, group R-L21, brand R1b.
Maternal haplogroup l2.
For those interested in further DNA research in our Craton ancestry, I encourage you to get in touch with Eric Craton who heads up the Craton DNA Project and is quite knowledgeable about DNA sequencing and interpretation of data. Eric has done considerable research into our branch of Cratons and is quite well-informed on our line. (Those wishing to contact Eric, please write to me for his contact information.)