Finding Distant Relatives with Autosomal DNA Testing

Jan14

Maybe you tested your DNA to prove or disprove a genealogical theory. Or maybe you tested to check on your health risks or carrier status. But now you see all these possible 3rd to 5th cousins in your family finder or relative finder lists and you wonder if you are related and if you can find that relationship. Perhaps you contacted a few and had almost no responses.

DNARelativesSampleSYes you are probably related, but without both of you having a good paper trail you would be most lucky to actually find that relationship. It is likely to be further back than suggested if your ancestors were at all endogamous. Just living in the same location for a few hundred years can lead to much inadvertent intermarrying and more common DNA than degree of relationship would expect. So autosomal DNA testing is no genealogical shortcut. Some of the people you contacted already know this, so if they saw no common surnames or places on your profile they may have lost interest.

So be prepared before contacting those likely 3rd to 5th cousins.

  1. Have an easily readable pedigree chart in both PDF and online format (GEDmatch can do the latter, more on GEDmatch later)
  2. Another good tool is a list of about 12 generations of ancestors by place name. Much easier for a possible relative to scan.
  3. Do some reading on the basics. UPDATE 9-sep-2018 See my article – http://blog.kittycooper.com/dna-basics/
  4. Try to talk some close relatives into testing so you have more data to work with
  5. Last but not least, make a decision on how much time you want to devote to this project … warning it can be addictive

If you want to do the minimum, then scan the localities and surnames of these possible cousins and contact the ones with surnames or place names in common with you. Indicate in your message that this is the reason for contact. Include the URL for your pedigree or family site and offer to send the PDF files. Include your email address if you are using the 23andme messaging system. The more directed the contact, the more likely you will hear back. I recently went through and cancelled some of my early invitations and send new improved ones on the lines above and got four new shares.

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Common Ancestors Can Be Very Far Back

Dec24

So far I am finding that the common ancestors with Dad’s DNA matches at both 23andme and FamilyTreeDNA are much further back than predicted. We have found the MRCA for only those distant cousins with good paper trails and perhaps even a tree at GENI like we have.

Most of these matches are only one or two segments and the longer the segment the more likely it is to be a real match with a discoverable common ancestor. I actually found a new 5th cousin of mine through DNA, Dad’s 4th cousin once removed. She has a one segment match of 17.14 CMs and 2849 SNPs in common with Dad and our common ancestors are in the 1700s at farm Fatland in Etne, Hordaland, Norway (online resources for Etne research listed at familysearch.org)

23andme shows you all your 7cm and larger matches but many genetic genealogists think anything less than 10cm is suspect. My view is that if Dad’s match is also a match with either me or my brother (n.b. frequently the match is for fewer SNPs and CMs in the next generation) then it is real, even at 6cm. As you can see in the chart, we have found many common ancestors with smaller than 10cm matches. GEDmatch lets you look at even smaller segment matches with specific people as does Family Tree DNA.

Here is a summary of the most recent common ancestors in Norway that I found for Dad with some of his DNA matches:

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Chrome Browser Tools for 23andme

Dec8

I just found out about two wonderful browser helpers for 23andme that work only in Chrome and installed them both. So far I am absolutely delighted with them.

  • 23++  totally redoes the 23andme inbox so you can search by name or subject. Since I have a few hundred messages by now this is essential. I had been continuing many conversations via email partly because the inbox at 23andme was so limited. This addon also adds functionality to the relative finder, as well as other features
  • 529andyou collects data in your local chrome mySQLlite database every time you look at the table comparison in the ancestry lab Family Inheritance Advanced and puts an icon on the far right side of the url box at the top that you can click to see this data

So my first effort with 529 was to look at my three 5th cousins that are all descended from Isaak and Sara Steinhardt:

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New Ancestry Composition Tool at 23andme

Dec7

There is a terrific new tool at 23andme for looking at your ancestry. Cece Moore describes it in great detail on her blog post here. I very much like the chromosome mapping part but the colors are incredibly boring if all your ancestors were european. Just shades of blue that were hard to distinguish one from another. So I changed the colors for Finnish, British, Ashkenazi, Eastern and non-specific Southern European

Here is my picture (I am half Norwegian and half German with half of the German being jewish, so a quarter Ashkenazi):

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