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Tool to find common ancestors at GEDmatch

Jul4

Whenever I get a new good-sized DNA match, I try and figure out how we are related. Ancestry and MyHeritage both have clever tools that search your tree and the trees of other users to come up with the likely relationship. Of course both you and your match have to have a family tree connected to your DNA on those sites for that to work.

My father’s DNA matches with matching ancestors, first run

GEDmatch has just released a tool for its Tier 1 (paid) members that will search for the common ancestor you have with your DNA matches on that site. This capability requires both you and your match to have uploaded a GEDCOM to GEDmatch and associated it with your kit. I just updated my 2015 blog post about using GEDCOMs at GEDmatch which explains much about them, so click here to read it. By the way, a GEDCOM is a text file that is formatted especially for genealogy programs; it lets you move the facts in your tree from one genealogy web site or program to another.

The new tool found nothing on my mother’s side. She was German and half Jewish. There are almost no Germans at GEDmatch and my one known half 2nd cousin on there has no tree uploaded. As to the Jewish side, very few have their trees far enough back to meet mine. I need to get a few of my known 3rd cousins to upload GEDCOMs.

The above listing, partially repeated below,  shows all the common ancestors my first run of this tool found for my Norwegian-American father using the default settings on the form. I have cut off the first 3 columns on the left which have the kit number, match name, and email address for privacy; also that makes the image readable on this page!


Let’s look at the rest of the columns for my Dad’s top match. Clicking the tree icon would take you to the user profile information. The cM shared are listed next; 40.3 is match that can be anything from a 4th to an 8th or even more distant cousin. Then the name of the possible shared ancestor, first in my GEDCOM and then in my match’s GEDCOM; either one can be clicked on to go to that person’s tree entry. The 8G is how many steps down from that ancestor my Dad is. If you click that, you see a descendant list from that ancestor in your tree. Notice that his match is also 8 steps down, so in the same generation. Subtract one to get the cousin level so this is a 7th cousin.
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The Genetic Detective, Gedmatch, and me

Jun27

I am loving watching the Genetic Detective on ABC every Tuesday night and I really hope you are too. It is a new true crime series starring CeCe Moore which demonstrates the use of genetic genealogy to catch rapists and murderers. As someone who uses similar techniques to solve unknown parentage cases, it gives me great joy to see this show and share it with family. I even announced its debut to my blog’s mailing list.

If you do not get ABC in your television package, you can view it on HULU or wait a week and click here to see it on the ABC website.

It was a lecture by CeCe back in 2012 that got me started on this DNA pathway. After I solved a few of my own family mysteries, I started writing this blog and helping others with their quests. Now I even teach at the i4GG conferences she organizes every year (videos available).

What I hope my friends and family get from this show is a better understanding of how DNA sleuthing works and why they should upload their DNA results and a family tree to GEDmatch and Family Tree DNA to help solve crimes like these. What is most enjoyable for me, is that each week so far there has been a slightly different genealogy challenge for solving the case.

Photo of my TV showing my Compact Segment Mapper at Gedmatch from episode 5

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Finding a relationship with DNA segment data

Jun12

Ancestry has spoiled us all with its tree and ancestor matching tools; so much so that I almost never look at the actual segment data any more. Ancestry does not provide that anyway. When autosomal DNA testing first came out, you had to look at the segments on each chromosome that you shared with your matches in order to figure out relationships. Personally, I kept a master spreadsheet of DNA segment data for all my Dad’s matches from the different sites (click here for the post on how to do that or here for all the posts on that topic).

Comparison of my father to various Fatland cousins at Family Tree DNA, names added by me

The raw DNA data from Ancestry can be uploaded to a number of other sites in order to do chromosome comparisons and see the segment information: GEDmatch, Family Tree DNA ( ftDNA), and MyHeritage. You can see if you have good matches on those other sites without paying, but to unlock them on the latter two sites will cost a small amount. GEDmatch is free but it has extra tools that are available for a nominal charge and of course it can be used by law enforcement if you have opted in. Please do so and watch Cece Moore on the TV show the Genetic Detective to see why!

How is the segment data useful? It helps when you have many segments assigned to specific ancestors because of who they are matching with. Then when a new DNA relative appears you can figure out which line they are related on based on their shared segments with you and your relatives. Many people prefer to use the chromosome painting capability at DNApainter rather than spreadsheets to keep track of segments. I have been keeping my Dad’s sheet since 2011 so it’s just easier for me to add new relatives there.

I recently noticed that Dad had a 33.5 cM single segment match (I do not include the many segments less 7cM) on Family Tree DNA to a Norwegian named Jan Olav Risvold (who gave me permission to use his full name). Normally I ignore single segments, but this one was large and fell in a section of chromosome 2 which is well mapped for my Dad, so I took a look. Also Vold (Wold) is a family name, so perhaps?

Screenshot of Dad’s master spreadsheet with segment data, Jan is the first line, colored by side

One problem with segment data is that you cannot tell which side it is from without other relatives to compare to. Luckily for us, my brother and I have often inherited different segments at the same location from our Norwegian-American Dad. Therefore by comparing them to other cousins we can tell whether they are from his mom or his dad. Jan matches my brother on that segment but not me. Thanks to a 6th cousin, Frode, who shares 22cM at the same location with my brother and dad (see image at the top of this article), we had previously identified the ancestral couple that this DNA came to us from, our Fatland 5th grandparents, Ole (1696-1772) and Brita. on Halsnøy Island in Hordaland. They are our ancestors via Dad’s maternal grandad Henry H. Lee from Skjold farm in Etne, Hordaland.

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The 23andme Family Tree built from DNA

May31

The dream of every genetic genealogist is to be able to build a family tree from just DNA. 23andme made a terrific start on this with their Beta family tree released in October. Now it is out of test mode and they have added good editing facilities. Being slightly obsessive, I tried it out with almost everyone whose login I have (my family and many friends and clients).

My paternal side tree built with DNA at 23andme is accurate (fixed one cousin)

I find it useful to fill in the names of my ancestors and the child from which my cousins are descended. On my own tree I was able to remove an incorrect generation turning a 3rd cousin into a 2nd cousin. I also like the compact display with nodes for each ancestor and the ancestors of tested relatives. Click here for an excellent and detailed help document at 23andme.

Major missing features are 1) no ability to export the tree and 2) no capability to share it with family members. Those are big drawbacks for serious genealogists like me. The other problem is that I cannot figure out how to get it to recalculate a tree although the documentation refers to that a number of times.

The family tree that 23andme builds from your DNA relatives only includes those who have opted into open sharing or those with whom you have “connected” via that button on their match page. According to the documentation there is a limit as to how many people you can have in a diagram plus the initial trees are built from your closest 20 matches. You can add people to the tree and there seems to be a provision for new relatives going into a side box and getting added from there. I did not see any cases of that.

My Norwegian Dad’s tree is completely accurate. The right side has just relatives on his mother’s tree and left his father’s. I have figured out or been in touch with all his listed matches. The only one I cannot vouch for is a woman who, based on her other family matches, has a different great grandfather from the one on record (it seems to have really been one of my grandfather’s brothers, a widower preacher in that neck of the great plains). No, I have not pursued this after no response from her to several delicately phrased emails a few years ago.

The only inconsistency is that there are several matches from Dad’s Halling great grandparents that do not show on his tree but show on mine.

My Jewish husband Steve’s tree was most interesting as it showed all his DNA relatives as being from one side which was incorrect. Possibly because Jewish people from the same geographic area, Galicia in his case, will always have some shared DNA from past cousin marriages. The key with Jewish matches is to look at segment sizes.

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Who is my great great grandfather’s daddy? A ThruLines experiment

May3

My great great grandfather Jørgen Oleson Wold, 1816-1892, from Skougar near Drammen, Norway, was born 9 years before his parents tied the knot. Although his father is listed as the man his mother eventually married, DNA testing has stirred up my doubts.

Having a child out of wedlock was not uncommon in rural Norway of the 1800s. It was not considered shameful in many areas. Often the couple would marry later on; you had to be able to support a wife in order to have one. Another reason is that people wanted to be sure they could have children before marrying, since many hands were needed on the farm. The data shows that quite often women were pregnant at the altar. Click here for an article showing that having a sexual relationship and getting pregnant was the normal way to start a marriage in at least one area of Norway at that time. Night visiting, fully clothed, was a customary way for young people to get to know each other.

According to the 19th century clerygyman and sociologist Eilert Sundt (my 10th cousin 3R), who looked carefully at many population statistics, 43% of all Norwegian children were conceived before their parents got married back in the mid 1800s. Click here for the article that cites this.

The problem for Jørgen’s parentage is that there are no DNA matches on just his father of record’s line. It is always possible to get less DNA from one 3rd grandparent but it seemed that all my family’s matches to the descendants of other children of that marriage were smaller than expected. We also have many matches quite far back on Jørgen’s wife’s line, suggesting it was possible we just had more DNA from her side but also demonstrating that when there are many generations of large families, DNA matches to 5th and 6th cousins will be found. This is also true on our other Norwegian lines.

Could Jørgen have a different father? If so, I would expect to see a group of 4th cousin matches who match each other but are not assigned to any of our known lines. Since Norwegian records are good, our ancestors are well documented back into the 1700s or even earlier.

There is a large group of matches that fits that scenario, all descended from one Torkild Westby b 1810, Drammen, Norway. It so happens that Westby/Vestby is a farm in Skoger just outside of Drammen where Jørgen may have lived as a youth. Norwegians did not have surnames back then, they used their father’s name plus their farm of residence which could change. Also W was pronounced as V in Norway so they are interchangable in the spelling. When Torkild’s children came to America they used the surname Westbye. I found the birth record for Torkild in the Norwegian archives and sure enough, he was born on farm Westby in Skoger..

Torkild’s birth and baptism record in the Skoger Churchbook for 1810 – http://urn.digitalarkivet.no/URN:NBN:no-a1450-kb20070402610138.jpg (3rd from bottom on right)

I decided to try a ThruLines experiment by changing Jørgen’s father to Torkild’s father, Jahn Jahnsen Westbye, in my Ancestry tree and see what happened. For Jørgen’s father and grandfather of record, Thrulines listed no DNA matches that were not also listed for his son.

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