April 19th, 2014


DNA matching my genealogy

In my last post, I wrote about the estimates that Ancestry.com made regarding my ethnicity based on my DNA results. That wasn’t why I took the test though. I wanted to see which family lines I matched. By that, I mean I wanted to find other people who have enough matching genetic markers to indicate that we are related.

Ancestry classified the matches into three categories for me.

  • 3rd cousins, with 98% confidence
    While there may be some statistical variation in our prediction, it’s likely to be a third cousin type of relationship—which are separated by seven degrees or seven people. However, the relationship could range from six to ten degrees of separation.
  • 4th cousins, with 95% confidence
    For relationships this distant from you, there is greater statistical variation in our prediction. It’s most likely to be a fourth cousin type of relationship (which are separated by ten degrees or ten people), but the relationship could range from six to twelve degrees of separation.
  • distant cousins, with 50% confidence
    As far as DNA goes, you do have a fair amount of shared DNA with this match, however the relationship is distant if it exists at all.

Ancestry found one third cousin match, eight fourth cousin matches, and 101 pages of distant cousin matches. I’ve looked through the online family trees for many of them to see if matching ancestors can be found.

The family tree for the predicted third cousin only goes back to their great grand-parents. To match at 3rd cousins, they’d need to go back to their 2nd great grandparents. However, I’ve done descendancy research on all my 2nd great grandparents, and none of the people in that research match people in her tree. There’s enough holes in my descendancy research from 3rd great grandparents that it’s possible she could fit in there, particularly in the Solle/Hein line, where I haven’t found my 3rd great grandparents yet. I think it’s also important to note that Ancestry gives the confidence at 98%, which means there’s a 2% chance their prediction is wrong.

Of the fourth cousin category, I was able to find common ancestors for four of the eight predicted matches. Three are third cousins, once removed. One is a sixth cousin, once removed.

Of the distant cousin matches, I was able to find three other people with common ancestors. One is a fourth cousin, once removed. One is a 5th cousin. And one is a third cousin, once removed. Third cousins, once removed, are popular in my results.

The Big Tree fan chart with DNA matches marked
The Big Tree fan chart with DNA matches marked

The chart above (click to make large) shows the family lines where matching people were found. Three of the third cousins once removed matched Parker/Murphy, Ryan/Sheedy, and Voigt/Thuernich, which are all lines from my paternal grandfather and where I’ve focused a lot of my research energy. One third cousin once removed matched Samms/Cornell, and the remainder matched either at James Washington Annis or his grandfather Ezra Annis. All of these are my maternal grandfather’s family and I’ve barely scratched the research surface in that branch.

The short conclusion I take from that is my research on my paternal grandfather’s family has some genetic support for being correct. There’s still some room for error, but it’s pretty good evidence.

I should also mention there’s one predicted match where I don’t have a common ancestor at this point, but that person’s family tree comes heavily from the area of Piteå, Sweden. That’s where my maternal grandmother’s family is from, so I suspect a match will be found there as well.

And for the benefit of people searching for names on Google, here are the ancestors with matches.

  • Patrick Parker and Mary Murphy
  • John Ryan and Deborah Sheedy
  • Johann Voigt and Mary Agnes Thuernich
  • Edgar Marion Samms and Ella Orinda Cornell
  • James Washington Annis and Elizabeth Davis (2 matches)
  • Ezra Annis

Originally published at King Rat. You can comment here or there.