Wednesday, August 16, 2017

Imprecise Science Part 2: MyHeritage

After the less-than-encouraging analysis of my AncestryDNA matches to see what percentage of my matches also match my parents (only 69%), I took a look at MyHeritage. These are matches obtained by uploading our raw test data from the AncestryDNA tests to theMyHeritage website (currently a free process), rather than by taking MyHeritage's native tests, so results may be impacted by that. MyHeritage is also a newer entrant to DNA testing/matching.

Suffice to say, MyHeritage currently makes AncestryDNA's match processing look good.

I have 97 matches at MyHeritage (excluding parents and great-uncle), so a much smaller sample size than AncestryDNA. It's just as well, as MyHeritage doesn't currently have any tools for working with or analysing your matches (and there aren't any external tools for this either as far as I know), so you have to look at each match manually and record the necessary details to do any analysis.

4 of my matches, or 4%, also match my Mum.

Another 4 of my matches, or 4%, also match my Dad.

So that's a 92% rate for false positives for me and/or false negatives on my parents.

Of the 4 maternal matches, MyHeritage reports me as having more (generally around double!) shared cMs with that match than my Mum does for 3 of them. The paternal matches were a bit more plausible, only one of those showed me as having more shared cMs than my Dad did.

Side note - there's no ability to search matches by birthplaces in their tree at MyHeritage, so no easy way to locate any Wing descendants yet.

[UPDATE Jan 2018: MyHeritage rolled out a new matching algorithm in January 2018. I now have 1476 matches in total, with 590 or 40% shared with my Mum, 452 or 31% shared with my Dad, and therefore 434 or 29% false postives/negatives. This is much more in line with the match percentages I obtained from AncestryDNA. Well done, MyHeritage, the new algorithm looks much more feasible].


Debbie Kennett said...

I thought I was doing badly at MyHeritage with 71% of my matches not matching either of my parents:

Your results are just crazy.

Unknown said...

I recognize a few of the names of those on our match lists either from GEDmatch or the "Big 3" testing companies. Of the few people I've contacted whom I don't recognize and who have uploaded to GEDmatch, there was zero matching DNA -- so I'm not bothering to do anything until they sort out their matching algorithm, which is seriously flawed. My sister and I both have matches that don't appear on our parents' match lists, but I haven't done the calculations for the %. I hope that MyHeritage does manage to get their act together and provide matches we can be confident in, and also, of course, provide the matching segment information.

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