Matches, MRCA, intermarriage, endogamy and My Heritage tools

+3 votes
Good Morning.

My dad’s mother’s side, Nova Scotia and New Brunswick planters and loyalists whose families before they came or subsequently intermarried considerably, meaning when you are looking at multiple MRCA and internal endogamy in either or both sides of the matches.  

When autoclusters came out (and as I discover supplemented with clues from theories of family relativity and maps), they promised that would provide the ultimate avenue to cutting through all the above confusion created by the above situation - prevalent here and of course in the American colonies now constituting New England in my example.


Yesterday, I received a coast to coast enquiry about a decent sized match with my dad.  Both of us had reasonably developed trees which also helped.

As we walked through the possibilities, we came across one and then a second couple of my dad’s third  great grandparents.  Now i have found actual DNA matches to one of these couples - but not through her (and of course that does not mean that we are not related through them). but had we we not had the autocluster, we would have stopped there,  

But she was in my autocluster 14 and on working on all the group, I came across the ACTUAL common couple related to that match, there was only one common couple, who happen to be both my dad’s fourth great grandparents and 5th great grandparents (We descend from an older and a younger daughter).  In fact, because of that nuance, we can determine which of the couple that it came from.  

So my question is what will that do to the language of analysis.  We may have most recent common ancestors MRCA - might we need to add to our vocabulary ADCA (actual DNA common ancestors) who may or may not be the most recent-or the only recent  - and of course on some cases, this may be shared if there are multiple independent segments.

I should note that will these tools, based on a scan of my dad’s remaining 20 autoclusters, the predominant number due to large families and 100s of samples that I will actually be able to hive off several actual accurate pinpointed DNA matches.

So it seems that in these cases which are not that uncommon, the traditional acceptable match statement will become woefully inadequate and in fact misleading and confusing.  

As an afterthought, it shows that some very legitimate paper matches will still be accurate but that portion may not have been passed down in one or the other matching pairs - so non matches should not lead to false conclusions and it may be reassuring to some potential testers.

We don’t change for change sake but when it is successful, we need to do so or become irrelevant it seems.

Any common experience or thoughts on the matter?
WikiTree profile: Enid Newcombe
in The Tree House by Lloyd de Vere Hunt G2G6 (7.6k points)
It is for this reason that I also tested my parent's remaining siblings, because I had noticed marked differences in the matches that my brother and I ended up getting.  I reasoned that by testing parent's siblings we would increase the chance of capturing the "last match in the line" ie the people that shared DNA with one sibling but not the other.  My father and his sister have three autoclusters each that the other does not share, as well as innumerable non shared matches at Ancestry.
Hi, I think the dna painter website would be a good tool for you to help compare your dna common ancestors with your dna matches.

Basically it allows you to make a family tree for your dna where you can keep track on which ancestors go back to which chunks of dna.

They have a video to help new users figure out the site.  It is free to use.

Good luck!

2 Answers

+2 votes
Nice Work, Lloyd!

I'm looking forward to the day when those of us with endogamy have mapped the chromosomes sufficiently that we will have developed little (or big!) segment charts that new-found cousins can compare against - and thus know which set of ancestors those segments were likely to come from!

My tangled branches are near yours; mine are in the Peticodiac and include some planters and loyalists as well as Palatinate-type Europeans.  There may be some common factors in our search!

My focus for now has been on trying to document 100 DNA matches (a number picked at random, but obviously i will need a lot) who have complete trees where some lines go back to the Peticodiac and the rest clearly don't.  Obviously having only one line going back would be a big bonus!  But as you mentioned in your case, very well developed trees are necessary to draw any conclusions.

I am very interested in your observation that this work will push our vocabulary!  Please keep us all posted on what you discover!


by Shirlea Smith G2G6 Mach 6 (63.8k points)
+1 vote
What you may be missing is that for a genetic relationship of that distance, you need to have a triangulated match between three testers.  Presumably the third tester is from the auto-cluster you described.  The MRCAs in this context are the closest ancestor(s) that all three testers share.  It doesn't matter that two might be related in a different way because the third tester shows that that chunk of DNA came from a different ancestor.
by Kerry Larson G2G6 Mach 8 (83k points)
There  are 4 on the group which are related to a single ancestor and will find more when I join in those slightly below the autocluster size requirement. I have between 12 to 15 autocluster which will each proved heir unique ancestors - and so on ....

The other people I mentioned were the MRCAs who where not part of that actual DNA match for this one - which came from the fourth and fifth double great grandparents for me
The two individual testers whose match is listed on the profile are father and son.  For a triangulation there would need to at least two more individuals descending from different legs of the MRCA who all match each other in the same place on chromosome 3.
You need to have a triangulated match for Wikitree confirmed button. You don't need triangulation to actually prove a more distant ancestor, though. A good DNA network is just fine.
Sorry I have no idea what you are talking about

I said that I have a father who has multiple common ancestors with a massive number of matches.  They are divided up fortunately by several auto clusters which each number 3 or more.  As a result, I will be able to determine what is the Actual DNA couple - or individual match

I have not entered each one in Wiki because none of the hundreds that would end up there use Wiki - so I am not sure whether it might be a violation of privacy to actually lay out their tree or reference them - unless I could simply enter them in up my line

The issue there of course is that in the first couple or three generation you would have scores or entries until each breaks off to rest at the actual DNA match

So maybe WikiTree is not fully amenable to this level and precision within the current template and it best remain - elsewhere and abandon WikiTree

However as described above each element working together with the documentary flow which is essential to filter in and out based on migration, and rogins and these other factors and also filtering in DNA

The other problem that the lack of rigor overcome by the above process is that in cases such as I have illustrated and would be fairly common in the CO-traveller and endogamy mix - is that otherwise invariably most of the “proven DNA” would be pointing to the wrong couples creating further confusion among the community of true matches shown in the testers for that common ancestor. So that is the big while in your present system

Any suggestions on how WikiTree might improve to adjust to more precision than is currently available?
Hi Davis

I was typing my response when yours came in on mobile so didnt see it pop up - this looks like a good lightweight approach
Hi, well any living people on WikiTree without an account will be unlisted.  So it is okay to fill out the world tree down to your matches and send an email invite to wikitree and leave anyone living as unlisted.

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