Saturday, March 20, 2010

Digging Deep into My Roots

23andMe’s Relative Finder predicts Yvonne STEWART is my “Distant Cousin.” That means she would be greater than a 10th cousin. Up to “Distant Cousin” Relative Finder assigns a range around its prediction. For example the prediction might be 4th cousin with a range of 3rd to 6th cousin. Yvonne and I have one matching segment of DNA on one chromosome comprising just .07 percent of our total DNA. That is the only segment we both have from our shared ancestor that is at least five centimorgan’s long (the minimum threshold for Relative Finder to call a match).

When Yvonne and I first looked to see if we could find a shared ancestor in our pedigrees, I couldn’t find one. She later pointed out to me that I was mistakenly looking in my mother’s line when our match was in my father’s line (Yvonne did not match my mother). If Yvonne and I were 11th cousins we would have to share a 10th great grandparent. If I didn’t have the same person in more than one of my lines, I would have 4,096 10th great grandparents. I know I don’t have 4,096 unique 10th great grandparents, because my parents are 4th cousins, one time removed. I expect my parents' lines merge at other places in our family tree also. Nonetheless, there are a lot of possibilities at the 10th great grandparent level, and I do not know the names of many of my 10th great grandparents. In fact, my pedigree chart has many blank boxes after my 2nd great grandparents, so I doubt I will be able to find a shared ancestor with many “Distant Cousins.” Any shared ancestor with an 11th cousin I do find may not be the ancestor from whom I have inherited the segment. However, I expect to have a lot of fun looking (and I also expect to learn a lot in the process).

A couple of weeks ago I contacted another of my Relative Finder matches. In that case Relative Finder predicted we were 5th cousins (with a range of 3rd to 10th). I sent her a link to my pedigree, and she recognized the WYATT surname as being one in her pedigree. She told me Mary Ann WYATT, born in Rowan County, North Carolina in 1839, was her ancestor. I went to and found a family tree that showed her Mary Ann’s WYATT line was Noah (1805-1871), Thomas (1773-1846), John (1743-1815), John (1714-1776), John (1679-1738). This last John married Rachel CALLOWAY (1675-1719) on November 17, 1696, in Albemarle Precinct, Perquimans County, North Carolina. John and Rachel are my 7th great grandparents, so the lady I matched is my 8th cousin. If the shared segment passed down both lines it came from either John or Rachel. I chart all my matches. I will be watching for another person who shares that segment with me. Perhaps I can then figure out whether the segment came through the WYATT line or the CALLOWAY line.

I mention this WYATT/CALLOWAY line because Yvonne and I then found we share a WYATT ancestor, the Reverend Haute WYATT (1594-1638). He was the brother of Sir Francis WYATT. Francis WYATT was the first colonial governor of Virginia. Fortunately, both are well-documented. As it turns out, the Reverend WYATT is my 10th great grandfather, and he is also Yvonne’s 10th great grandfather. So, Yvonne and I are 11th cousins. She is descended from Reverend WYATT’s first wife, and I am descended from his second wife. That means if we did inherit our shared DNA from this line, it had to be from Reverend WYATT.

If nothing else, Relative Finder is causing me to get to know my WYATT line a lot better. It is also causing me to extend every line I can in my pedigree to try to find why I match the people I do at 23andMe. I am learning a lot about my family history as I extend those lines (and I am having a lot of fun while doing it). I am also meeting some very nice new cousins.


Ray Vick said...

Of the Vicks in the YDNA project who have autosomal tests, do you see much genetic correspondence?

James Larry Vick said...

There are just eight other men who are members of our VICK Y-DNA Surname Project who are also members of our VICK and Allied Families DNA Project at 23andMe. Y-DNA proves that one is not a descendant of Joseph Vick of Isle of Wight County, VA (our immigrant ancestor). So that just leaves seven who I share a patrilineal line with. Of those seven, I don’t know the exact degree of cousin I am to two of them. While they share Joseph’s Y-DNA, they don’t have the VICK surname and do not know their line to Joseph. I do think from their Y-DNA results they are greater than 7th cousins. I match one of the two. The Relative Finder prediction is within the cousin range I would expect us to be, but I cannot be sure that the shared segment we inherited is from a VICK ancestor.

Of the remaining five Y-DNA project members, one is a 6th cousin, one is a 7th cousin, two are 8th cousins, and one is an 8th cousin, two times removed. Looking at the Relative Finder FAQs, I have less than a five percent chance of matching any of them since they are 6th cousins or more distant. As it turns out I do not match any of them.

If I broaden my comparison to all members of our 23andMe project (other than the children or grandchildren of a project member) who are descendants of Joseph, I have the possibility to match 25 of them. Of the 25, 22 are 6th cousins or greater. So, I have less than a 5 percent chance of matching any one of them in the patrilineal line. That would mean I could expect to match about one of them. I do match three of them. Whether the shared segment is in fact from our VICK ancestors, I don’t know. Hopefully, with more cousins testing we can isolate the shared segments and trace them to a specific ancestor.

Of the remaining three project members, one is a 4th cousin. The probability of a match with a 4th cousin is about 45 percent. I have a 3rd cousin two times removed (a 3rd cousin two times removed would be the genetic equivalent for comparison of a 4th cousin). Finally, I have a 4th cousin, one time removed. Since the probability of matching a 4th cousin is about 45 percent and the probability of matching a 5th cousin is about 15 percent, the probability of matching a 4th cousin, one time removed is between 45 and 15 percent. So, if you roll up the numbers I would expect to match about one of the remaining three, and I match one (the 4th cousin).

I hope that answers your question.