Saturday, March 3, 2012

More DNA tests means more information

I love the puzzling-it-out aspect of genealogy DNA investigation. I’ve now had two known cousins (both on my father’s side) and more recently my father contribute DNA tests. We are using Family Tree DNA. With each additional test comes a big increase in possibilities for narrowing down which part of my family tree is relevant to each of my matches.

I thought it might be of interest to see what I am learning from these tests, despite not yet finding the paper trail to any of my previously unknown matches! I’m very pleased to say though that the results confirm the paper trails to my father and known cousins. A big Phew! there – those relationships are close enough that surprising DNA results would most definitely not be welcome.

When I had only myself tested, this was the extent of my knowledge about my 103 matches:image

Note: I’m using all my current matches which include my father and cousins throughout this post for illustration purposes.

Not very helpful.

Then, two known cousins tested. I discussed the results of one of those cousin’s tests here. With Family Tree DNA, once a known relationship is confirmed by both parties you are able to see which of your matches you have in common with that person. As I am not controlling their accounts, I don’t have access to my cousins’ match lists, just to who we have in common. Both of my known cousins are connected to my French branch but their “matches in common” with me didn’t overlap with each other. In total, I was able to pencil in ten of my matches as somehow connected to my French branch. My cousins are actually half-cousins, so it narrowed down the possibilities to just one eighth of my tree for those ten people.  

This is the state of my knowledge after my cousins tested:image

At new year my Dad agreed to testing. That was very much to my surprise as he had previously turned up his nose at all attempts to discuss it. His test results came back just a few days ago, and what a lot of extra information they provide!

  • by comparing his results with my cousins I see that 10 matches are connected to my French family (no change here yet, but this number may increase when both my cousins have confirmed their relationships with my Dad)
  • as well as those ten, 28 more of my matches are somewhere on my father’s side of the tree
  • my remaining 65 matches must be from my mother’s side of the tree
  • PLUS I have names for 48 new matches on my father’s side of the tree.

This is what the state of my knowledge looks like now:

image

So far I have only looked at name lists, but even that gives a great starting point for when I compare notes with my matches. I am thinking through the steps to run this sort of analysis in an automated way so I can update it easily as new results come in.

I think it really shows that it’s the more the merrier, so far as DNA testing is concerned! I wonder who else would be willing to part with a bit of spit…

This is just step one. There is a whole lot more narrowing down that will be possible once I start looking at the data on the matches themselves (ie, the location of the match on my DNA) but this post is quite long enough for one night.

6 comments:

  1. Hi Shelley, Very encouraging. How many markers for each member of the families? Cheers, Viv Martin

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    1. Hi Viv,
      The Family Finder test is autosomal testing which will identify matches in any part of your tree, not just the direct paternal or maternal lines. Rather than a few dozen markers they test 710,000 SNPs. Matches are only reliable up to 5 generations back, but you do get some matches with people who are much more distantly related. The trick is finding out which part of your tree your matches belong to. I've had no luck establishing my connection with any of my matches yet!
      Anyone related to you and I would fall in the "Father's side" 48+28 set of matches if they show up at all. I might be able to narrow that down a little more with the next step I have planned.

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  2. I have Dad's, Mum's brother and my own results on FTDNA Family Finder. It was very interesting to compare matches and predicted relationships. (I have Mum's and my own results on 23andMe & that provides another group of matches to check.) It certainly helps when you know which side of the family to look at. I like your idea of methodically working out the branches.
    Cheers, Kerry Farmer

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    1. Thanks Kerry, I have at least two more steps planned which I hope will let me squeeze out a few more clues.

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  3. Great post Shelley! Yes, having more family members test opens up so many more possibilities. I've had several test and I love how it helps narrow down possibilities.

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  4. Hi Shelley, I just ordered a Family Finder test today with the Family Tree DNA sale price. I have been reading back over your posts with interest, thanks. Looking forward to seeing what matches I can find.

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