Sunday, July 4, 2010

Comparison and Analysis from 23andme's Ancestry Finder

After working with my Ancestry Finder tools for awhile, I have done a few basic comparisons. Any chart can be viewed larger simply by clicking on it.

Here is my basic view:
 Here is my mom's basic view:
You can see that my mother has many more Finnish segments than I do, but I have a substantial Irish segment on Chromosome 11 (11.3 cMs) that my mom does not.  From this, I can deduce that my father passed me this segment. This begs the question, "Did my father have Irish ancestry of which I have been previously unaware or is this Irish ancestry connected to his immigrant British Australian grandfather?"

Here is a shot to show the information that is displayed when the cursor is moved over a colored segment:

Here is a shot of my overall Finnish segments from the Advanced View. In this shot, I chose a minimum segment size of 5cMs and matches who have grandparents from up to four different countries. When the cursor is moved over the Finnish column, all matches except Finnish ones fall away.
Here is the view of my mom's chart with the same settings:

These charts show the effect of the Finnish contribution being halved in my genome. My mom is 50% Finnish and I am 25% Finnish.

Here is my full advanced view set at a minimum of 10cMs:
Here is my mom's with the same settings:
Notice that she does not have any matches on the X Chromosome at this setting, but I do. Therefore, my match must be from my dad's X Chromosome. Since my dad's X only came from his maternal side that narrows it down to Norwegian or Australian English origin.
Let's take a closer look. This is what my X match looks like with the cursor hovering over it:

From this analysis I can deduce that this match who has three grandparents born in Canada and one in the US is related through my father's mother's ancestral lines. Interestingly, so far on Relative Finder I have no known matches on my X Chromosome. Therefore, this example also demonstrates that this tool is providing information that was previously unavailable to us.

Lastly, take a look at my chart with the segment setting at a 10cMs threshold and matches with (at least) three grandparents born in the same country:

 And my mom's at the same settings:
From comparing these I can see my father's contributions (Ireland and Canada) among my matches on the chart.


Here is the Tutorial  Screen:

And the Advanced Controls Help Screen:

My Conclusion:
I believe this tool will prove to be useful to many of us and, at the very least, interesting and entertaining to the rest. It gives us an overall look at the ethnic background of our genetic matches as well as our parents' individual ethnic contributions to our genome if we have been able to test at least one of them. Further, as demonstrated by my match on the X Chromosome, it does give us some limited information that was previously unavailable in regard to some of our matches on Relative Finder who have yet to accept our many outstanding invitations. That, in itself, is a positive step forward. Keeping in mind the inherent limitations of an application that utilizes user-submitted data that's scope only reaches back a couple of generations, in my opinion, this is a welcome addition to the tools available to individuals in their quest to discover as much as they can about their genome.


  1. Very cool,

    You guys that tested at 23andme are having all of the fun. I hope FTDNA gets busy with whatever they have up their sleeve.

  2. Thanks for sharing this!



  3. Wonderful tool! Thank you for such a clear and excellent presentaion.

    Question: All of the grandparents on my father's line back to the 5th GGP, except for about 6, were born in the US; all known immigrant ancstors on his side (5th and 6th GGP) were born in Germany. What will this tool show?

    My mother's line is more "eclectic" and should prove interesting!

    Regards, John

  4. Thanks all,
    At Larry's request, I added the tutorial screen and the advanced controls help screen. This should give more clarification to the images and analysis.
    John - It remains to be seen what this tool will show for each individual mix of ancestry. I think it will depend on the settings that you choose. If you exclude the US matches (by checking the box on the middle right in the Advanced View), you very well may see German up near the top of your list, like I do for Finnish. Additionally, since one can adjust the threshold control all the way down to 5cMs, this will likely pick up more distant ancestry. For example, at the lower end of the RF threshold (5cMs-8cMs), many of us are finding the likely connections to our matches way out at the 7th-10th Cousin level. Therefore, it goes to follow that you will see that more distant ancestry represented on your chart at those settings as well.
    I am looking forward to the evolutionary process and forward development of these types of tests! This is just the first step.

  5. I tested both of my parents. Unfortunately, I discovered that more than 50% percent of my matches aren't shared by any of them. I wrote to 23andme trying to understand the issue, and they simply explained that the algorythm doesn't pick up every match we actually have. It depends on many factors. The smaller the segment, the greater the chance that it will be missed. I can't remember exactly, but it said something like it picks up 1 in 4 3rd/4th cousins, and just 1 in 8 6th/Distant cousins. Therefore, that Irish match you display on the X chromosome could well be from your mother side. I have a long Italian segment on the X chromosome too, that none of my parents have. No doubt it's real though, as my father is indeed Italian.