Friday, August 31, 2018

DNA: Case study: Floyd Covington

Initial question


DNA analysis indicated a fairly strong ("confiance élevée" = high confidence?) quantity of shared DNA with a "DNA relative". Browsing through our list of common matches (persons whose DNA indicates they are related to both of us), I noticed a few descendants of John Covington and Mary McLaughlin. So I sent a note asking if my match knew their relationship to John and Mary.

Wrong family


I got a response giving my the names of grandparents and great-grandparents. I was able to easily find John H. Covington and wife Augusta in census records, together with their son, Floyd. Since John H. was born in  I was able to find Floyd and his wife, Linda, in later census records. Among the many records that I sought, I found all of these people also in a FamilySearch family tree. But I also fairly quickly discovered some problems. First, I was not looking forward to researching this connection. My extensive research into the large Covington family had followed them from Tennessee (though some born in North Carolina) to Arkansas to Texas to Oklahoma. This John H. was born in Mississippi. I know of no Covingtons in our branch that went to Mississippi, so a connection would be a related family in North Carolina in the late 1700s - lots of work to uncover! Then I also discovered that their son, Floyd A., never married a Linda, and stayed his whole life in San Antonio, Texas. The Floyd and Linda I was researching moved to California and raised a family there. A more general search of records found another Floyd, Floyd G., born in Texas at about the same time, in about 1903. But I couldn't find Floyd G.'s parents.

Stuck in public record: search my own data


I tried another tact: search through my existing family database for a Floyd Covington. We had a Floyd, also born in Texas in about 1903. So now I tried tracing the life our our Floyd Covington, and ran into enough circumstantial evidence that I'm convinced the DNA match I contacted is descended from a Floyd already known in our tree.

Clarifying my search


I focused my efforts on finding the ancestry of Floyd Covington and Linda Prince. Since I my original interest was common DNA with Covington descendants, my main interest was in Floyd's ancestry.

Findings


Floyd G. Covington was born in Texas in 1903 to Richard A. and Fannie Prince. Yes, his mother's family name was the same as his future wife's family name. For a future reference, Richard was the son of James Mattis Covington and his second wife, Winnie Watson. According to posted family trees, Fannie Prince was from a very large family and was a close sibling (near in age, only two years apart) of Jasper Prince. In 1910, Jasper was a recently married farmer with three very young children. Claud Covington, the oldest of Richard and Fanny's children, was living with them and working on their farm. In 1913, when Floyd was 10 years old, Fannie passed away, leaving his father with ten children between the ages of about 1 and 21. In 1920, another of Floyd's siblings, his older sister Wilma, was living with the Princes. By the way, one of the Princes was Linda, future wife of Floyd, born in 1908 in Texas. Also in 1920, 17 year old Floyd was living with his newly married brother, John B., and his wife, Sarah. John in a butcher; Floyd also works in the meatpacking plant.

The move to California


In 1930, John and Sarah Covington are living in Maywood, a district in Los Angeles, with two more Covington brothers, Ray and George. All three brothers are butchers. Floyd, meanwhile, (and now shown as Floyd G.) is living in the Phoenix area with his new wife, Linda Prince. (An source citation posted online says they were married there in the late 1920s. By the early 1930s, Floyd and Linda had moved to Maywood, too, where they began to raise a family.

The DNA math


Ancestry.com predicts, based on quantities and lengths of identical DNA segments, that the two persons tested are fourth cousins. According to my family tree software, the relationship between the two, if I am correct that the Floyd who married Linda was the son of Richard Covington, 1/2 3rd cousins once removed. A mouthful, to be sure. The 1/2 is because Richard and our direct ancestor, John (not John H!), had the same father, but were from different wives. Hence they share only some of the father's DNA. The once removed means one of the two persons tested was a fifth generation descendant from their common ancestor (James, the father whose kids are from different marriages), while the other was a sixth generation descendant. No doubt this is more math than many are comfortable with. But the important math to understand is that for each generation of descent, the shared DNA is halved, on each side of the relationship. For example, compare first cousins to second cousins. The child of a first cousin shares half as much DNA from an ancestor as his/her parent does. This is the same for the child of the other first cousin. So second cousins share 1/4 as much DNA from a common ancestor as their parents did. In the case of our Covington relatives, the main relationship is third cousin, but the 1/2 cuts the shared DNA by half and the once removed is another half. Taken together, the shared DNA is 1/4 that of 3rd cousins, which would be mistaken for fourth cousins, the relationship predicted by Ancestry.com .

Recap


The Floyd Covington who married Linda Prince was Floyd G. (some have posted Gabriel), son of Richard Covington and Fannie Prince

My reasons for reaching that conclusion are:
1) The son of John H. and Augusta, also Floyd, married one time, to Margaret Arend, and remained in San Antonio, Texas until his death in 1973. He was not married to Linda.
2) Floyd G.'s mother's maiden name was Prince, increasing the probability that one of her son's might have met/known a Prince family member.
3) Floyd G.'s oldest brother, Claud, was living with Linda Prince's family in 1910.
4) Floyd G.'s sister, Wilma, was living with Linda Prince's family in 1920.
5) At least three of Floyd G.'s siblings moved to Maywood/Los Angeles shortly before Floyd & Linda.
6) My claimed relationship of 1/2 3rd cousins once removed between the two individuals whose DNA was analyzed would result in a far less complicated prediction of  4th cousin, which matches Ancestry.com's prediction.

What?


Normally, I would focus on facts and strive to be more concise and less wordy in an explanation of a relationship. My emphasis here, though, was in showing a process that might be involved in making connections with relatives through DNA. The DNA in this case only played the role of (a) identifying a definite relative to contact, and (b) strengthening confidence in the result. I would add, that this is in many ways an easy connection. Connecting through common ancestors that are outside of your family tree and generations beyond your current research is more typical, and records are much more difficult to find.

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