DNA match on MyHeritage but not on Ancestry

[David Nicoll]

Hi,
   A couple of further points.

   Yes heritage matching is a game, based on the companies database.
   Hence the recent change in the Ancestry database results.
   I have gone from about 60% Scot’s to 60% Germanic, both correct, but from a genealogical point of view the revisal is pointless. It is simply saying that a vast percentage of the population of the UK came from the continent in the last 3 thousand or so years, so we share a lot of DNA.

  The Timber algorithm does not have a specific cM cutoff, it is simply that if you have a match who shares multiple short matches, this is likely to be a more distant relative.
  The white paper shows that for the Timber algorithm, they have made assumptions that may be true in the USA, though not for longer established families. Which is that people are unlikely to be doubly related.
  This is I would say wrong in Europe, before the Industrial Revolution people did move but generally populations were much more stable. So people were much more likely to be doubly related.
  The Timber algorithm means that they deliberately throw away match data, (partly at least on financial grounds), which are matches at the 7th to 8th generation level.
  This means that you may miss that critical match to the family who know more about their ancestry, and take you back to 1700 or beyond.
   In the USA it means that long established families may not be able to match their DNA in Europe, similarly hamstringing research.
   See the Ancestry white paper on matching for the detail.

https://www.ancestrycdn.com/support/us/2025/01/2025matchingwhitepaper.pdf

[Steve3180]

I am trying to understand why someone's Ancestry DNA profile is showing as no match on Ancestry but yet shows 60cM on MyHeritage?

We have both done Ancestry DNA tests, linked them, and then imported the DNA profile into MyHeritage.

Can anyone please help explain this?

I'm not sure there is a simple explanation for this, neither Ancestry's Timber nor MyHeritage imputation would account for it as, as has been said, both sets of data originated on Ancestry and were imported to MyHeritage.

I would start by getting a third opinion, GedMatch would be best as it gives you more control over the matching parameters, but FamilyTreeDNA would also work.

You actually have a really good opportunity to examine the differences between Ancestry and MyHeritage matching but it would involve a fair bit of work.

[David Nicoll]

I assume, and John may correct me, that the 60cM match is made up of several low cM segments in which case Timber is very much in play.

[ABradley]

Hi I did not expect to find so many people withe the same problem.
Some time ago I uploaded my DNA from Ancestry to My Heritage.
Recently MH have matched me with two first cousins once removed (different families)
I have checked out both families and found nothing in common.
They don't know me nor I them. I contacted the sister of one who was on Ancestry who was not a match to me.

Has anyone been matched so close?

Andrew

[David Nicoll]

Hi,
   I have had a not dissimilar situation, but I was fortunate in the person in questions father had also tested. From that I could see that the child had matches from both father and mother, he had about twice the cM match to me than his father. I was fortunately able to trace back and find the MRCA on both sides. This was in fact around 1770.
More localised pedigree collapse can also make the MRCA seem much closer than it really is.
   

[AnotherDay]

Hi Andrew.

How much DNA (in cM) do you share with these new '1st cousins once removed' (1C1R) on MyHeritage? Usually, 1C1Rs share around 400 cM.

MyHeritage does sometimes seem to inflate the amount of shared cM - but that tends to be for distant matches (e.g. 45 cM instead of 22 cM; 60 cM instead of 35 cM; 35 cM instead of 20 cM).

If MyHeritage says you share 350 cM or 400 cM or 450 cM with a match, then that's probably going to be pretty accurate.

Do these new 1C1R match each other? Does the one with the sister on Ancestry match you on all the family lines that you should match? Does her sibling on MyHeritage match you on all the lines? Does the Ancestry person (A1) match you with people who are on MyHeritage? Do the new 1C1Rs on MyHeritage (MH1, MH2) match you with people who are on Ancestry?

Is your age similar to the ages of A1, MH1 and MH2? Do A1, MH1 and MH2 have ancestors from the same area as your ancestors? Have you been able to narrow down the family line on which you match A1, MH1 and MH2?

[LizzieL]

I would start by getting a third opinion, GedMatch would be best as it gives you more control over the matching parameters, but FamilyTreeDNA would also work.

Gedmatch helpfully tells you where the data is imported from
I have looked at a few people who like me have imported from Ancestry.
Ancestry seems consistently a few cMs lower than Gedmatch
JR  Ancestry 62  Gedmatch  67.6
GW Ancestry 37  Gedmatch  52.1   (unweighted on Ancestry 48, which is also longest segment)
MK  Ancestry 32  Gedmatch  37
ID  Ancestry 32  Gedmatch 36.3

GW was the surprising one until I checked the unweighted cM

[ABradley]

To.   AnotherDay

Hi thank you for your interest. The following are hopefully the answers to your questions.

MH1 matches with me --- 344.6cM
MH2 matches with.       --- 288.4 cM
MH1 does not match me even on the extended tree I have constructed for him.
His sister on Ancestry is not a match for me.
MH1 would appear to be about 20 years younger than me. His sister on Ancestry is 8 years younger than me.
I also “ share” 29 other matches with MH1. His niece matching 197.3 to me as second cousins daughter and 2017.3 with him. The remainder are 3rd to 5th cousins to both of us.
Yes MH1 has family connections to the area I was born. In fact he was born quite close.
Among the ten top matches four share the same family connections. Although two of them are siblings.
MH1 and MH2 do not share any matches.  MH2 is rather more difficult due to lack of detail on the person involved.
If my MH1 and MH2 are related to me , it cannot be to the degree shown.
I have no maternal uncles and I think it safe to say all my known paternal uncles are accounted for. MH1 has a known father on his tree.

Andrew

[David Nicoll]

Hi,
    Have you put these numbers into DNA painters shared cM Tool?

     https://dnapainter.com/tools/sharedcmv4

     It is quite informative.

     You would seem to have one of two scenarios, or a mixture.
     
      An NPE somewhere
      An example of pedigree collapse.

      From your description of shared matches at the 3rd to 5th cousin level, pedigree collapse seems the most likely.

      The DNA painter site is suggesting that without pedigree collapse the ling could be 6 generations back.  Have you got back that far?
      Are there any known cases of cousins or second cousins marrying? These will both skew the numbers.
      To understand this you are going to have to build as big a tree including as many of your matches as you can.
      The What are the odds tool (WATO) may help you here.

Happy Hunting