Sunday, November 20, 2016

Y-DNA Raises Thomas Kirk From The Dead

The hunt for Thomas Kirk's (1778-1846) ancestral origins is a challenging journey.

Following his paper trail has been, at times, frustrating. Destroyed census enumerations for Ohio and Virginia, probate packets incinerated in courthouse infernos, and the spotty existence of 18th century records have created a perfect storm that shields Thomas' secrets from his modern-day descendants.

Despite these frustrations, the seemingly impenetrable brick wall occasionally yields small cracks that emit glimmers of sought-after insight if not outright answers (thank you tax and land records).

However, in examining only the documentary evidence, answers about my 5th great-grandfather's origins story remain elusive.

Fortunately, the science of DNA provides an alternate tool to bypass the records and peer back in time.

Answers Written In The Stars Double Helix
Who was Thomas Kirk's father and what was his ancestral extraction? Where was he from? Was he Scotch-Irish? Or just Irish? Or just Scots?

Could DNA, and specifically Y-DNA, help answer these questions?

As the chromosome responsible for making one a male, Y-DNA is passed - largely unchanged - from father to son for generations. This unchanging inheritance down the patriline is a powerful resource when researching paternal ancestry.

As a direct male descendant of Thomas Kirk, my Y-DNA should be very similar to his Y-DNA. Although he died 170 years ago, his paternal genetic markers still walk the earth.

With the western tradition of surnames passing down the paternal line of descent, Y-DNA has the potential to help us locate other men who have more of Thomas Kirk's family history.

Eliminating The Genetic Mutations
I could test my Y-DNA, but, on its own, would that be the most accurate representation of Thomas' Y-DNA? Occasionally, bits of the Y-DNA code - its individual numeric markers that make it unique to Thomas - may change during the inheritance process. Generally, we're not talking major changes, but enough to alter a marker or two from the values Thomas' Y-DNA originally contained.

With nearly two centuries and six men between me and Thomas, I wanted to take steps (just short of exhuming and testing his remains) that would provide the closest and clearest picture of his Y-DNA.

By expanding the group of test takers, it is possible to attempt to control for these mutations.

Thomas Kirk had seven sons who lived to adulthood and had sons of their own. By testing direct male descendants of each of his sons, we could identify the most common reoccurring values - the mode - for the group's Y-DNA markers.

The group's most prevalent markers (what's referred to as the "modal haplotype") are important, as genetic genealogist Maurice Gleeson noted, "because on the balance of probabilities, this is the genetic signature of our Most Recent Common Ancestor (MRCA)." In this case, the group's MRCA was Thomas Kirk.

Finding and Testing The Men
I spent the past year tracing the descendants of each of Thomas' seven sons. Through months of focused genealogy and countless messages asking distant cousins to provide genetic samples for testing, we steadily built a Y-DNA Kinship Group.

This week, the Y-DNA Kinship Group was made whole. Results came back from the lab for descendants of Thomas' two remaining sons to be represented among the test takers. The group of distant cousins consists of third and fourth great-grandsons of Thomas Kirk who live in seven states across the U.S.

Descendants of each of Thomas' sons have now contributed to a more refined picture of his Y-DNA. Collectively, we have accomplished the first phase of our initiative:

  • Locate and test direct male descendants of each of Thomas' seven sons.
  • Identify the group's most frequently occurring Y-DNA markers (modal haplotype) to give us the closest understanding of Thomas' probable patrilineal DNA.

With this information in hand, we can now focus on our search for men who are genetic matches to this specific modal haplotype. 

Will we locate Kirk matches in the U.S. who have secreted away hidden pieces of the paper trail (I'm rooting for a family Bible)? Or will we find Kirk matches in a small Irish village where the family has lived for centuries always wondering what happened to their rogue relatives who set out for the New World? 

Only time, dogged determination, and DNA will tell.

For a more thorough overview of Y-DNA that I admittedly glossed over in this blog, I recommend reviewing the ISOGG Wiki.

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