Thursday, January 2, 2014
X-Chromosome Matches by FamilyTreeDNA
Back in November, the project administrators got together and made a list of all of the things we would like to see implemented in the new FamilyTreeDNA website. One of the items, a matrix designed to show which of your In Common With matches were matches to each other, was implemented most recently. This upgrade has already been a huge help to me in working with my matches and trying to determine common ancestors.
Another huge improvement came out this New Years – X Chromosome Matching! With this new tool, you can now see who all of your X – chromosome matches are in addition to your autosomal (chromosomes 1-22) matches. Having this ability allows you to narrow down who the common ancestor might be between you and your match.
Before we see how this works and how it might benefit your research, let’s go over a little bit of background information. Males have 1 X and 1 Y chromosome. They get their 1 X from their mothers. Females have 2 X's, so they get 1 X from their mother and 1 X from their fathers. Because I am female, I have 2 X’s, which means I got 1 X from my mother and 1 X from my father. My mother also has 2 X’s, therefore, she got 1 X from her mother and 1 X from her father; however, my father only has 1 X that he got from his mother. He did NOT get an X from his father. Therefore *I* did not get any X chromosome DNA from my father’s father.
There are a couple of X chromosome charts out there to help you figure out who your X chromosome ancestors are. Here is the fan chart, which is one of my favorites. WikiTree will also allow you to see who all of your X chromosome ancestors are. I have identified my X chromosome ancestors directly in my genealogy software. For each of my X chromosome ancestors, I have added a photo of an “X” in either a pink box for females or a blue box for males. In my pedigree below, you see that my father Timothy received only 1 X chromosome from his mother; therefore his father Darrel did not contribute any X chromosome DNA to me.
Since I’ve had my paternal grandfather, Darrel Smith, DNA tested, I would have to create a new chart if I wanted to follow HIS X chromosome ancestors. In that chart, his mother, Reba Fox would have a pink X beside her name because she contributed to Darrel’s DNA.
In order to see your X chromosome matches, log in to your ftDNA account as usual and bring up your Family Finder matches.
Click where it says “Show All Matches” and select “X Matches” from the drop down list:
Now you have a list of all of your X Chromosome matches. Here is my list. You see that my paternal grandfather, Darrel Eugene Smith, is missing from this list:
That is because I did not receive any of my X chromosome from him.
My X Chromosome matches can be viewed in the Chromosome Browser just like the autosomal matches can.
Lucky for us, ftDNA also incorporated a brand new feature which allows you to load your matches directly into the Chromosome Browser from your match list and compare. To do this, simply click on the little arrow below your match’s name to unhide the advanced options, then click the “+ Compare in Chromosome Browser” option to load them into the Chromosome browser. You are still limited to loading only 5 matches at a time into your chromosome browser (at this time).
Once you have your matches selected, click the Compare button to open them in your Chromosome Browser:
Here is a comparison of my Mom, maternal grandfather, and paternal grandmother who all match me on my X chromosome:
You can also filter on X matches in the Chromosome Browser:
I am looking forward to diving into my X chromosome matches. What about you? Do you have your X chromosome ancestor chart ready? Have you found any connections on your X chromosome yet? If so, please tell us about it below.