Wednesday, 30 August 2017

Another MyHeritage mystery

Previous posts have documented some of the vagaries experienced with MyHeritage's DNA matching.

This one makes me wonder how those without an ability to compare at other companies would even  realise that they may be missing a close match!

I expect that some matches may well be false positives given the imputations MyHeritage does to compare test kits from assorted companies, but I didn't expect to NOT find a match reported as predicted 2nd cousin by Ancestry, 3 generations by GEDmatch and predicted 2nd to 3rd cousin by FamilyTreeDNA.

The comparison details:

Ancestry: both tested there
Predicted relationship: 2nd Cousins
Possible range: 2nd - 3rd cousins
Confidence: Extremely High
Total shared: 208 cMs over 11 segments

FamilyTreeDNA: one tested, the other transferred in from recent-ish Ancestry test
Predicted 2nd to 3rd cousins total 202 * cMs, largest segment 57
* effectively 175cMs when < 5cM segments excluded

GEDMatch: one uploaded from FTDNA, the other from the recent-ish Ancestry test #
At the defaults for one to one comparison:
Largest segment = 56.2 cM
Total of segments > 7 cM = 212.5 cM
11 matching segments
Estimated number of generations to MRCA = 3.0

# these kits being the same used for the MyHeritage uploads.

This has been reported to MyHeritage Support for their comments and explanation.


  1. And here is MyHeritage's rather inadequate response:
    Dear Ms. Henderson,

    Thank you for contacting us.

    I understand that you got different DNA Matches with other providers. MyHeritage uses three different parameters to calculate DNA matches: Total amount of shared DNA, number of shared segments, and the length of the longest segment. The algorithms and thresholds that are used to calculate matches vary between the different providers, and therefore you do not necessarily see the same matches in the different sites.

    Best regards,
    MyHeritage Support team
    I have suggested that this is an unacceptable response and perhaps he, or his manager, could explain which of the three parameters a match three other companies show as over 200cMs, with at least 10 segments over 7cMs shared, longest segment of 50+cMs, and 2 others over 20cMs might not meet!

  2. Update from MyHeritage:
    We apologize for this and your case has been forwarded to our scientists, who are refining the algorithm for the DNA matches, for further investigation.