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Anomaly on Myheritage matches

A

AlanB

LostCousins Member
Can someone explain this, I'm confused?

I have a known 2nd cousin 3xremoved (RA) with whom I share 35 cM on Myheritage. I know that his mother (TH), who is my 2nd cousin twice removed, has also tested on Myheritage because one of my matches gave me access to her results and TH is amongst her matches. However I do not match TH so I assumed that I must be related to RA through his father too.

A few days ago, TH's mother (SF) appeared amongst my matches on Myheritage. SF is my 2nd cousin once removed. I share 75 cM with her.

Now here is the strange thing. When I look at my shared matches with RA and SF, I find three triangulated segments. One of them is small (5 cM) but the others are 12 and 14 cM. Surely if I share the same pieces of DNA with a lady and her grandson, I should share those segments with the person in between too. Why don't I match TH?
 
I found the answer! RA, who manages all 3 accounts, responded to a request I made to upload to Gedmatch, and I do in fact match both him and TH with a 14 cM segment on chr 17. It seems that the Myheritage algorithm sometimes fails to pick up a match when you upload from elsewhere (as I did).
 
AlanB said:
It seems that the Myheritage algorithm sometimes fails to pick up a match when you upload from elsewhere (as I did).
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That's the problem with different providers sampling different SNPs - it affects the statistical analysis (as you may well find if you adjust the settings at GEDmatch).

It's the reason why I decided to re-test with MyHeritage earlier this month - when I get the results through I'll do a comparison against the test I transferred from Ancestry.
 
peter said:
It's the reason why I decided to re-test with MyHeritage earlier this month - when I get the results through I'll do a comparison against the test I transferred from Ancestry.
Click to expand...
Did you get the results of your My Heritage DNA test and were they any different from those from your uploaded DNA?

I have only uploaded (Ancestry) DNA to My Heritage. I find that my DNA cousin matches there are mostly outside the UK and those that are in the UK don't tend to have very extensive trees. I like the My Heritage triangulation feature though.
 
CliveR said:
Did you get the results of your My Heritage DNA test and were they any different from those from your uploaded DNA?
Click to expand...
Not yet - the sample only arrived at the lab a few days ago.
CliveR said:
I have only uploaded (Ancestry) DNA to My Heritage. I find that my DNA cousin matches there are mostly outside the UK
Click to expand...
That'll be the case at every site - partly because the descendants of emigrants are more likely to take a DNA test, but also because the greater natural resources in the New World allowed the population to grow more quickly.
 
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