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14 December 2014

Can DNA Help Solve Two Dunham Brick Walls?

Can DNA Help Solve Two Dunham Brick Walls?

I hope to find the answer to this question, with the help of some cousins and some people I haven't met yet.
By way of background, my second cousin, Christina Streiff, and I have a brick wall ancestor named William F. Dunham, born in Pomfret, Vermont in 1799. Separately, Selma Blackmon has another brick wall named Jane A. Dunham Couch, born in Rome, New York in 1823.

Are Our Two Dunhams Related?

If so, it would provide a major clue regarding their ancestry. We have two documents suggesting they may be related.
First, Selma has a document showing an 1840s real estate transaction between her Jane Dunham and our William F. Dunham's son, Lindsey, when both families lived in Oneida County, New York.
Second, the death certificate for Jane's daughter, Carrie Sarah Couch, listed her mother (incorrectly) as Jane Hempton. The informant, Jane's granddaughter, got it wrong. But Hempton is the (uncommon) married name of William's daughter, Louisa. It suggests the two families knew each other.
We continue to look through records, though so far we have not cracked the case.

Along Comes DNA Testing

There are three kinds of DNA tests for genealogists (aka genetic genealogy):
  • Y-DNA tests track a male's straight paternal (i.e. surname) line, which is not a fit in this case.
  • Mitochondrial DNA (MtDNA) tests track everyone's straight maternal line - again not a fit.
  • Autosomal DNA tests, though, might be useful.
First through fourth cousins generally share DNA with each other, and people also can share DNA with some more distant cousins. If William F. Dunham and Jane Dunham were first cousins, then Selma and I would be fifth cousins, so it was worth a try.
Selma and I had both taken autosomal DNA tests, and when we compared them, we found that we share one small segment of DNA on one chromosome. It might not sound like much, but we share enough (10cM) to know that we have common ancestors.

Finding Common Ancestors

If you've been down this path, you may know that two matches' common ancestors could go back hundreds of years. But there are ways to narrow the search for the common ancestors.

First, we can test our own first and second cousins.

Selma is not a DNA match to Christina, but she is a solid match to another cousin of ours, Elton, on the same segment, and he is on the 25% of my tree that includes William F. Dunham.  By definition then, Elton, Selma and I have common ancestors, and they are from this branch of my tree.

Second, we can look for DNA matches in the general population that can help.

Does anyone match Selma and me?
Nobody at Family Tree DNA matches both of us.
One person at 23andMe is a match to me on the same segment, but I can rule him out, since he matches a cousin on the other side of my family on that same segment.
AncestryDNA does not provide chromosome-level data, so I don't yet know if anyone matches on the same segment. If someone is a DNA match there, and has Dunhams in their tree, I ask them to upload their results to GEDmatch, a free service that can show two people which DNA segments they have in common.


The Search Continues

DNA has not solved our Dunham questions yet, but DNA analysis does indicate that Selma and I are related, and that our two Dunhams may be related. The next step will be to test more descendants of these two Dunhams to see if they match us on the same segment.

As more people test their DNA for genealogy, a match could come from the general population at any time that could provide a critical piece of information to help us solve our mysteries.

Thank you Rich Capen for this article explaining our DNA and how we match. Through FamilyTreeDNA, we are now three cousins with one in CA one in WI and the other in GA. What other cousins want to join us? Contact me at sbgenealogy@gmail.com.