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General => Ancestral Family Tree DNA Testing => Topic started by: bethanyyd96 on Sunday 18 May 25 21:54 BST (UK)
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Hi I've just got my dna results in and I've got a question.
I've matched to a certain person that ancestry states is my 2nd great grandfather and it says I am the first matched to him and that there is no dna match with any other person. How accurate is this?
This person in question is the second husband of my 2nd great grandmother and in reality I should have no shared dna with him.
There is a question regarding the paternity of my great grandmother and if thrulines is true, this means the man in question is her father?
Kind regards
Bethany
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We do need a bit more information to help.
Birth dates of each person in your 2xGreat GM’s line.
The cM of the DNA match.
The match should have other matches who you both Share, it is very unusual not to have any Shared Matches. That said Ancestry only shows Shared Matches where the share is 20cM or greater, unless you subscribe to Pro Tools when you can see Shared Matches of low cM matches.
Thrulines accuracy can vary from 100% to 0%, you have to look at each individual in the proposed line and determine the accuracy of each one. They are, for want of a better expression, “cobbled together” from the trees that are on Ancestry and we know how inaccurate they can be.
I do not follow what you are writing that Ancestry is predicting, a DNA match is your 2x Great Grandfather as the likelyhood of that is that he was born c1900. My own 2xGGF’s were born in the mid 1800’s.
DNA is very accurate at determining actual biological relationships, questionable with very low cM, but above 20cM you can be confident that you are biologically related.
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I'm still trying to understand everything but I've added a screenshot the man in question, the lady next to him is his second wife, my 2x great grandmother.
Does this mean it's only a suggestion based on other trees? Because it's saying there are no dna matches?
Any help appreciated.
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I'm still trying to understand everything but I've added a screenshot the man in question, the lady next to him is his second wife, my 2x great grandmother.
Does this mean it's only a suggestion based on other trees? Because it's saying there are no dna matches?
Any help appreciated.
Hi Bethany,
That screen shot is from thrulines, which does not show you actual matches, it shows suggested ancestors based on a mixture of your tree and other ancestry trees. If you have a match with another tester that also shares the same relative in there tree, it would in theory show them when you click on that person in the thrulines page. However like Biggles says, it is not 100% proof of a relative its just a suggestion based on the trees ancestry has selected.
now in your case because its showing zero matches, there is no DNA connections (yet) its just a tree suggestion.
Richard
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That's fantastic thank you for your reply!
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That's fantastic thank you for your reply!
The suggestion is that you post the details of your (presumed) relevant line of ancestry: names, dates; and an overview of your shared matches: on the profile of your match there is a tab "shared matches" - overview the levels of cM show there.
Really, IMO, it's probably necessary to have someone have full access to your account who is familiar with DNA genealogy. Plus your tree. And that may only be a starting point. More often than not unknown matches can lead to inconclusive data, maybe just clues, partial ideas of ancestry etc. Depends on the amount and quality of DNA matches.
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Thrulines can sometimes be wrong though as they are based on what other people put in their tree. For example someone in my thrulines from the US didnt know about the Scottish naming convention so totally missed a generation and linked to wrong person.
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I'll just clarify that on ThruLines, the fact that you are related to someone through shared DNA is indisputable. What is sometimes incorrect is the way that Ancestry suggests you are connected. That is based on the content of other people's trees. Some people seem to have very reliable hints through ThruLines and others say it is really bad. I would say that mine has been 95% correct.
Zaph
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Yes you are related to the actual DNA test match but thrulines is based on what people have put into their own trees so if they just keep adding in lots of ancestry suggestions without verifying the actual record then the tree will be wrong in thrulines.
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Thrulines are only as good as the trees it uses and if those trees are wrong the thruline suggestion will be wrong too. Many just follow the paper trail and ignore the DNA when it contradicts the paperwork. An NPE or incorrect assumption about a parent are all it takes to throw a thruline suggestion out.
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I'm still trying to understand everything but I've added a screenshot the man in question, the lady next to him is his second wife, my 2x great grandmother.
Does this mean it's only a suggestion based on other trees? Because it's saying there are no dna matches?
Any help appreciated.
Yes, there can be discrepancies between what Thrulines show and actuals.
I rarely use Thrulines, I prefer to be within DNA > Matches, then apply Common Ancestors which is within the Filters menu.
I have worked through all my DNA Matches where the filter has been applied and link each of them into my Family Tree, being careful to validate correctly each one. Once they have been included in my Family Tree they are then assigned to a specific Group and each is then given a * to signify that they are included in the Family Tree and presently there are 149 DNA matches who have the *. Thus it is easy to see the status of those who still require research, those who are a mystery are assigned to a special Group.
Hope this helps.
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Thrulines does not consider clusters of DNA matches. It just looks to see if any presumed ancestors of yours is a presumed ancestor in your matches' trees.
My grandmother was born out of wedlock, and Thrulines suggested the entire line of her biological mother's later husband (not her father) was her own. Simply because he was from the same area, and among my matches happened to be ones who shared parts of his ancestry - enough to suggest that all of his lines and he himself was my ancestor. But there was no intersection of those matches. The alleged common ancestors were pulled out of multiple matches' trees who weren't related to each other.
This is the big issue for newcomers, there is a process and quite a bit of knowledge to doing this properly. It is easy for newcomers to just pick something out of Thrulines or their matches, where there isn't really a connection.
In particular if most of your ancestry is in a very concentrated geographical area, this can seriously muddy the intersections/overlaps of the matches. I have so many matches that come up with shared matches from multiple clusters, from maternal and paternal sides. I even suspected that one of my lines had infidelity on it. But it's just that almost every DNA match from that line, was also a DNA match from another line. I also have a few closer matches who are matches on both lines, and it's been those that have been key for unsorting those intertwined lines.
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Thrulines does not consider clusters of DNA matches. It just looks to see if any presumed ancestors of yours is a presumed ancestor in your matches' trees.
My grandmother was born out of wedlock, and Thrulines suggested the entire line of her biological mother's later husband (not her father) was her own.
Very much like my tree though my grt grandmother was married to Thomas but fell pregnant to 'John' with the last child (my grandmother). My tree shows John but is the only one to do so and the '1c' matches that only share 350cM just overlook the obvious as Thrulines uses the dozens of trees naming Thomas that are paper based.