I’ve just read an interesting article posted online by the Irish Times regarding Y-DNA with which I agree. There’s a lot of sales patter and technical jargon out there, but the principle behind genealogical Y-DNA testing is simple and logical.

The Y-DNA chromosome is passed along intact from father to son. A random mutation is likely to occur and that mutation is then passed along from the male in whom the mutation arose. The test itself quite simply identifies the most recent common ancestor, which is often turns out to be 27 generations ago in well-known databases.

From what I gleaned from a couple of folks who’ve taken the Y-DNA test, one might be naïve to believe that the results would only produce people with the same last name. For various reasons, people have changed their last name over time and then, of course, we have what genealogists apparently call “non-paternal” events.

In the United Kingdom alone, I would consider the possibility that the Scots left their “calling cards” in the north of England in the 1500s and likewise the English did the same when they travelled to Scotland to hammer the Scots. Don’t be surprised to find your Y-DNA results are listed in a database with a multifarious selection of last names.

A few months ago, I wrote an article Scotland’s DNA-Who Do You Think You Are? about DNA test cases revealing different Scottish clans who carry the M17 marker showing them to be descendants of the Vikings, in which I stated, “The MacLeod clan tests have shown that 47% of the men tested show that they descend from one individual, which means that 10,000 men alive today are descended from one man. “Among the remaining 53 per cent, researchers have found only nine other lineages present, showing that MacLeod men married women who were unfailingly faithful to them.”” Considering the Viking activities centuries ago, I doubt  being “faithful” was, in many instances, a choice.

According the article in the Irish Times written by John Grenham, the accuracy of tests can be varied. “If the size of the group being tested is not large enough, or the mutations tested for are not actually unique, the supposed “most recent common ancestor” can be as illusory as Santa Claus.” The Irish Times article discusses the brouhaha surrounding the well-known Irish TCD study that supposedly identified Niall of the Nine Hostages as the common ancestor of men bearing surnames of the Uí Néill origin.

Although I can’t opine from personal experience—yet—I’ve communicated with many people on this fascinating subject and often write about it on SpittalStreet.com.

There will always be the nae-sayers regardless of the field of study. The Irish times article tells readers toBeware of scientists who expect rigorous scepticism to be applied to scientific research, but think of genealogy as a sub-branch of the jarveys-and-heraldic-tea towel industry.”

DNA studies are rapidly evolving and will certainly prove to be more than useful in the field of genealogy and family history with the potential to break down a variety of brick walls and help people to validate their ancestry.

If you’d like to read the Irish Times article, click on DNA. Y? 

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2 Comments on The realities of DNA testing

  1. R. Johnston says:

    I had my Y-DNA tested and got lots of hits. The problem is that they are too far back for me to make any connections. You are right about the last names too. I’m still glad I had the test done because someone might arrive in the database where a connection can be made.

  2. Ben says:

    Very interesting article on DNA . Opens up so many unanswered questions for many people

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