Genetic Genealogy Using a Maternal Line, Case Study

 

John Wilson Davis Copiah County MS circa 1930

This is an account of an on-going genetic genealogy project of the family of Zabon Francis Davis. He was born in Marion County South Carolina in 1812 and died in Copiah County Mississippi in 1846. This is the line of my mother's father's people. I carry this Davis autosomal DNA, but I do not carry their Y-Chromosome. Y-DNA is only passed down from the direct male line.

One approach to this research is to gather autosomal DNA matches from that Davis line and then use the male Davis matches to proxy test. In short, this is how we obtained this Davis Y-DNA haplogroup, matches, etc. 

Now I know this family, or at least I thought I did. They have a well known oral and written history. The sources say that the family is Welsh and the immigrant ancestor arrived in the Pennsylvania Colony in the 1680s. 

We had our first male Davis Y-DNA test recently and viewing the results you could have knocked me down with a feather.  Why? Because, I assumed the results would pull up many Davis men and show obvious links to Wales... it did not. The Y-DNA matches included men with anglicised forms of the surname Ó Briain, such as O'Brien, O'Brian, Bryan, Bryant, Brian, etc. And, the haplogroup was the famous Dál gCais, i.e the descendants of Brian Boru. As I say, you could have knocked me down with a feather. 

Brian Boru AD 941-1014

This was a great mystery. What are the true origins of this Davis family.  The photo at the top of this post is my great grandfather John Wilson Davis born in 1848 and died in 1932. It was one of his Davis grandsons (my cousin that is) that provided us with the first Y chromosome DNA results. And, it was those results that created this mystery and showed obvious Irish ancestry from the County Clare Ireland area. 

Next task in the research is to test more Davis men from this line and see if they all carry this Ó Briain haplogoup, i.e. do they all match this Ó Briain family. 

I am also researching through the normal primary sources, census records, family Bible records, CSA military records, various land records, etc. I have already made several significant discoveries. I have located the Bryan family that I think is connected to the Davis family.  Their progenitor is Jesse Bryan born 1730, died 1794, from Marion County South Carolina. And yes, the Davis family originates from Marion County South Carolina. Both the Davis and Bryan families settled early there. It was the Georgetown District, and later formed into Marion County. 

In the 1850 Copiah County census I found a Bryan family living near the Davis family, and it included two Davis children. That was interesting. I had found a connection between the Davis and Bryan family in the primary sources. These two families knew each other, and obviously were aware of some connection.

Another point, the STR match between our Davis male to the many Bryan (and other forms of Ó Briain) matches were close, one only two mutations off. Additionally, there was a small army of other Ó Briain matches, some as far as eleven markers off, others much closer. This is using the 111 level Y-DNA test. This told me that the connection between the Davis and Ó Briain families could be placed in the 1700s. The closest matches reflected a mid 1700s time frame and the more distant matches reflected the Ó Briain lines prior to that. 

I found additional circumstantial evidence also, certain family names shared between Bryan and Davis families, geographic proximity, and the obvious Davis children living in an Bryan house close to other Bryan and Davis families. 

Now we will wait on additional DNA results. We are testing more Davis men from the Zabon Francis Davis line, just to confirm they all have the Ó Briain DNA. And, running more Autosomal DNA test to locate more immediate cousins so we can confirm the Davis Ó Briain connections in the lines of these particular two families. 

I do love a good mystery, and this one is splendid. I will post on this from time to time, as a help and guide to others that have come upon blocks, mysteries, in doing their family history. It will be a case study in genetic genealogy, using both Autosomal and proxy Y chromosome DNA.  

© Barry R McCain 2020