Sunday, November 1, 2009

Are You Ready For A DNA Test?

I can recall having to read The Double Helix, James D. Watson's account of the discovery of the double helix structure of DNA. For a 13 year-old more interested in sports, it didn't seem at the time to be very exciting or important - but it was required high school reading. Today, DNA is at the core of real and fictional crime drama - a simple cheek swab exonerates the wrongfully accused or alternatively, is the single most compelling evidence of guilt.

But DNA has really come to the forefront of genealogical research as well.

I am not a DNA expert but know from research that all of our family members share some common biology. All of our cells have a copy of our DNA. Females have XX chromosomes and males have XY chromosomes. There are therefore two possible DNA tests available - the Y chromosome test for the paternal line and the Mitochondrial (mtDNA) test for the maternal line.

The Y chromosome is passed on generation after generation between fathers and sons. Using the results of Y chromosome tests, a series of numerical markers, shows common paternal ancestors, with some changes over time due to mutations, and can show us our 'deep' ancestry including the migration patterns that occurred in our family lines. The results of testing won't tell us how we are related thus the continued need to research paper records. But most importantly, as more people explore their ancestry using DNA testing, our opportunities for collaboration continue to expand. By including the numeric marker results from DNA tests into databases, matches can be made and further family connections achieved. Because the Y chromosome is only carried by males, only males can take this test but women can ask their father, brothers, paternal uncles or nephews to take the test.

The mtDNA test is too broad to determine family connections but it can be used to weed out some of the Y chromosome test result matches and narrow down family connections.

I must admit that I have not yet tested my DNA although I am certain that such a test is in my future. It just makes good sense to take advantage of yet another tool in further exploring my ancestry. And, remembering the significance of my Scottish roots, the costs associated with these tests has dropped considerably with a good 33 marker Y chromosome test now available for less than $100. The more people who are tested, obviously the more expanded the databases become and the greater the opportunity for connections. So, is a DNA test in your future?

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