Many people who see that their ethnicity estimate from a DNA test is way off, think that they cannot trust the other findings from that testing company. That is a false assumption.
When you are shown people who share DNA with you, aka DNA matches, they really are your relatives, although some can be quite distant. What the relationship actually is may not be predicted very accurately, as many relationships share similar amounts of DNA. Examples of that are a grandparent and an aunt or a 2nd cousin and a first cousin once removed. Thus you are usually shown a range of possible relationships. Figuring it out from shared matches and trees can be lots of fun!
Recently “Gail,” a cousin of my South African 3rd cousin Sharon, contacted me about their match. The only common ethnicity that was shown for them at their testing company was Ashkenazi Jewish. Thus she was assuming that their common ancestors were Jewish.
However the problem is that Gail inherited her 2.7% Jewish from her mother who does not match Sharon. Gail has no Jewish on her father’s side that she knows of. My cousin’s 28% Jewish is from her maternal grandmother. That is the line where Sharon matches me (click here for that story). Gail does not match any other of my many many tested family members on that line.
One of the issues that people of Northern European descent have is that our ancestors intermingled quite a bit. This means that your Scandinavian could be my English and I suspect that is the case here. Another problem is that unlike relative matching, predicting your biological ancestry from your DNA is far from an accurate science (click here for my most recent article of many on that subject)
More accurate than ethnicity are the shared relatives. When looking at the matches Sharon and Gail share, I found a set of common ancestors among them that are from a non Jewish South African line.
Did you know that Ancestry can figure out how you are related to a DNA match if you both have trees linked to your DNA tests? You do not have to have anyone further back than your parents if other relatives have more extensive trees on Ancestry that include your family,
So how do you link your tree to your DNA? First log into Ancestry.com. Then click on DNA Result Summary in the pull down menu under DNA. Next click the gear on the far right that says Settings next to it as shown in the image below.
Once you are on the Settings page, scroll down to the words DNA and family tree linking. Then click that box to get to the page where you can link your test to your tree.
There you will see something like the below image where you can specify the tree and the person to link the DNA test to. When you start typing a name, Ancestry will use auto complete to show possible names from your tree. Once you have selected yourself or the person whose kit it is, click the blue button to make the connection.
Click this image for my slides demonstrating the DNA painter relationship calculator
My favorite calculator has long been the one at DNA Painterwhere the table is based on Blaine Bettinger’s collected data and the probabilities are by Leah Larkin based on the Ancestry white paper. It can work from a percentage or a cM value and lights up just the possible relationships in its table. Clicking on any table entry gets a histogram of frequencies. I have slides showing how nicely it works, done for a recent talk about 3rd party DNA tools for the SCGS jamboree. Click the image above to see those. That video should be available to attendees from the web site genealogyjamboree.com
Eight of the ten fully Jewish kits I have access to showed related parents in the “Are Your Parents Related” (AYPR) tool on GEDmatch. I am wondering if this level of relatedness (about a 4th cousin) is generally true among Ashkenazim and other endogamous populations. Or perhaps the GEDmatch parameters need some tweaking?
Sample related segment from a Jewish kit in AYPR
Also a number of married jewish couples I know have discovered that they share a DNA segment. Personally I share 11 cM on the X with my late husband even though I have only one Jewish grandparent. Most testing companies show me as about 30% Jewish.
I can understand that when people live in the same general area for generations, one could easily marry 3rd and 4th cousins. I also know that in the past, cousin marriages were not uncommon among Jews.
I invite all tested fully Jewish people to run that free tool at GEDmatch and then fill out my form on the next page. Please fill it out even when they are not showing as related to help with my statistics.
Aloha from my Hawaii cruise. Apologies to all of you for not getting any blogging or work done while at sea. My brain kept telling me I was on vacation!
One thing I like to do when cruising is to read fiction by the pool or at night. My new favorite mystery author is Nathan Dylan Goodwin who has a series about a forensic genealogist as well as a wonderful new series about a fictional genetic genealogy company called Venator.
I read the second Venator book first, The Sawtooth Slayer, which Nathan was kind enough to send me for a review. It stood up well, even though out of sequence. I then lent it to a friend who is neither a genealogist nor a DNA tester to see if it was an enjoyable read for her and others like her. She really liked it! She told me that now she is interested in doing her family history and maybe even a DNA test! So by all means give this to any friend who is interested in understanding what we do.
Next I had to get the first book, which I really liked also. The characters were particularly engaging. Then of course I started working my way through his other series, which is more genealogy based but still quite enjoyable.
Kitty drinking coffee at Kona Joe’s on the big Island near Kona