Thursday, January 2, 2014

FTDNA Releases X-Chromosome Matching Data

Family Tree DNA has just released the X chromosome matching exactly as they promised at their conference in November. (Yay!)

On the match interface, it is noted that there is an X match, however to see the size of the segments, one must go to the Chromosome Browser. Currently, in the Download All Matches to Excel option in the Chromosome Browser, the X chromosome data appears as Chromosome 98.

Thank you, Family Tree DNA for the New Year's gift!

The following are the release notes directly from FTDNA:

This week’s big release is X-Chromosome matching. It has been fully integrated it into Family Finder matching.

Here is the menu link to the Family Finder Matches menu.

On the Family Finder Matches page, there is a filter to show only X-Matches.


When you use the X-Match filter on a male Family Finder kit, you should get only matches from the maternal X-Chromosome.

Next, like other Family Finder Matches you can expand the advanced bar for a match and click to add the match to the Compare in Chromosome Browser list.

Matches are added to the Compare in Chromosome Browser list. You could go right to the Chromosome Browser by clicking on the compare arrow at this point.

Next we can also go right to the Chromosome Browser.

Here are three immediate relatives. The first two share X-Chromosome DNA. The third (green) one does not.

When we scroll down to the X at the bottom, we see that X-Matching is displayed for the first two but not the third.


Moving to the Advance Matching page, X-Chromosome matches have also been integrated.


  1. I'm happy for the excellent work FTDNA

  2. This is so cool! I am printing this out and heading into my account now! Such fun...

  3. Some interesting things - not sure if it's a glitch or there's some other explanation -

    One of my sons shares the following with a match:

    30.53 total
    9.00 longest block
    33.1 (one segment) on the X

    I am his mother and I do not have this match but my maternal half-brother does.

    100.55 total
    8.07 longest block
    34.14 (one segment) on the X - same place as my son shares with her.

    Why am I not a match to this person?

    I think it has something to do with who is getting the "Ashkenazi adjustment". My brother and I get it but my kids don't.

    My brother shares 30 segments with this match - typical Ashkenazi match with lots of small segments. Entirely possible he also connects on his father's side.

    Here's a question though - with lots of small segments on 1 through 22 but one large segment (> 30 cM) on the X should we be looking for an inheritance route that alternates genders? In other words - something like our mother's father's mother's father's mother's father's mother?