Many surname researchers have used traditional genealogy research methods without identifying their ancestor and his homeland. Genealogical DNA tests offer one more tool to help break through that brick wall and expand genealogy research by finding connections to other people in a family line.
DNA testing is not a replacement for good sound solid research. It does not prove exact relationships. It is but another tool in a researcher's took kit, which if used properly can help establish or prove ethic background, a common ancestor or spelling variations of the same family, such as Smyth and Smith. DNA results can also debunk ancestral stories and long held myths.
There are a variety of DNA tests. Each test reveals different things by looking at "markers." A marker is used as a definable segment of DNA with known genetic characteristics. It can all get very confusing fast. It can also get quickly expensive.
To make sense of the results they must be compared with other people's test results. Only then can conclusions be made. Warning, the results are not always easy to understand.
Two things are needed before a test can be taken. First, what exactly are you wanting to find out or "prove? Do you want to know if you have "Cherokee blood", or if descend from the clan chiefs on the Isle of Skye? Second, is there a living person who can provide a DNA sample in your line of interest? It could take some effort to discover and ask this person.
There are different companies that do DNA testing. Each is a little different and tests for different things. You must find the right company that has the best chance of answering your particular question.
According to Ellen John who addressed the Southwest Oklahoma Genealogical Society at their November meeting last week, the three most widely used tests are the mtDNA, the Y-DNA, and the autosomal DNA test.
Mitochondrial DNA is passed from a woman to her children and can be used to test direct maternal lineage. Both men and women can take an mtDNA test.
Since males have a Y chromosome, the Y-DNA test can be taken by males only. The transmission of the Y-chromosome down the male line is why it is useful for surname testing to determine if two males share a common ancestor.
An autosomal test looks at genetic markers found in 22 chromosome pairs which contain randomly mixed DNA from both parents. Men and women can take this test.