Announcement

Collapse
No announcement yet.

X DNA bug -- any clarification from FTDNA?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • X DNA bug -- any clarification from FTDNA?

    I have two XDNA matches -- one a full match and another a virtually full match on the XDNA. They do not match each other nor do they match any other XDNA matches. How do I determine which (if any) of ALL my FTDNA X matches is a viable match worthy of further research?

  • #2
    Originally posted by KayInFL View Post
    I have two XDNA matches -- one a full match and another a virtually full match on the XDNA. They do not match each other nor do they match any other XDNA matches.
    Do these two X-DNA matches also share any autosomal DNA with you? Normally they have to, in order to be considered a match at FTDNA. There was/is a glitch in some X matching at FTDNA, where a person would match someone on the full X chromosome, but had virtually none, or no matching segments on other chromosomes. I did a quick search of the forums, and found at least one post discussing this issue.

    I believe if that is the case with your two X-DNA matches (no matches on other chromosomes), then as mentioned in the above link, you need to contact FTDNA to see if they can clear it up.

    Otherwise, your name indicates that you are a female, so you have two X chromosomes: if they both match you on other chromosomes, one of these matches could match one X, and the other match the other X. How close of a relationship was estimated for these X-DNA matches?

    How do I determine which (if any) of ALL my FTDNA X matches is a viable match worthy of further research?
    In general, to determine if any of your X-DNA matches are worth further research, you should first use an X-inheritance chart to enter the names of your ancestors from whom you could inherit X-DNA segments. This will help you to see if a match is in one of those "X-inheritance" lines. You can find several types of charts to use, for the different inheritance patterns for males and females:Louise Coakley's article, "X-DNA's helpful inheritance patterns," has good information and charts so you can visualize and understand the inheritance patterns. She also has an "Excel Surname Template" to download, for X inheritance for both male and female.

    Another thing to keep in mind with X-Matches: with chromosomes 1-22, it is generally recommended that the minimum segment size to consider is from 7-15 cM. With X-DNA , you should double that, so minimum would be 15-30 cM to be considered a good match. You will need to view any match showing as an X-Match in the Chromosome Browser to see how large the segment(s) are, in order to determine if they are within that minimum range.

    Comment


    • #3
      I just saw something posted in a Facebook genealogy group, which said that a situation like this (if there are only small segments or no segments matching on the other chromosomes, but an almost complete or complete matching segment on the X), it is possible that the match was a transfer, perhaps of a synthetic kit (a file which was otherwise not able to upload, but manipulated in order to do so). Another possibility is the matching kit in question was one uploaded by Law Enforcement, if your kit has not opted out of Law Enforcement matching.

      Comment

      Working...
      X