Archive | December 2012

Common Ancestors Can Be Very Far Back

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

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

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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What to do at the GEDmatch site

A DNA cousin who just uploaded his ftDNA results to GEDmatch asked me what he could do with them, so I decided to write a blog post to answer this question. Here are my favorite things to do there:

  • make pretty pictures of your populations ancestry – called the Ad-Mix page
    (see more on that below)
  • get a list of possible relatives who have tested with other companies as well as the one you tested with, that is the “One to Many” option on your home page. Email addresses are shown but you cannot just click on them, you can cut and paste the first part but then you have to retype the ISP  (prevents spam)
  • look at a specific area of one chromosome to see who else matches you there – “Find people who match
    with you on a specified segment”
  • compare your GEDcom to one other to see of you can find that elusive MRCA
  • compare your GEDcom to all your DNA matches that have uploaded GEDCOM files

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