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General => Ancestral Family Tree DNA Testing => Topic started by: Towdlass on Sunday 14 June 20 17:07 BST (UK)
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I have a theory that the father of my paternal grandmother might also have been her grandfather. Is it possible for me to be able to tell if this might be true from my DNA results? Please don't be too technical when trying to explain to me. I have to admit that I am still learning about how to use DNA results. Thanks for any help or advice.
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I have a theory that the father of my paternal grandmother might also have been her grandfather. Is it possible for me to be able to tell if this might be true from my DNA results? Please don't be too technical when trying to explain to me. I have to admit that I am still learning about how to use DNA results. Thanks for any help or advice.
No, I don't see how you could determine this based on your DNA results.
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Do you mean that the man alleged to be her grandfather is actually her father? Would the birth mother be the wife of the "grandfather" or a woman from a younger generation? It could be possible to figure out but will require a lot of people testing and some luck. A little more information is needed for me to be clear.
Look at her alleged birth mother. Can you find other people who have had their DNA tested that match to any common ancestors in this line? Can you track down descendants of the alleged birth mother and persuade them to test? If you find matches to this maternal line, what about the alleged grandfather's wife's line? Negative results are not very informative but they can help.
It should also be possible to see the difference in numbers, but this will require some luck and a lot of descendant testing to be sure. Though until I can be clear on the scenario it is hard to say what to look for.
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Do you mean that the man alleged to be her grandfather is actually her father? Would the birth mother be the wife of the "grandfather" or a woman from a younger generation? It could be possible to figure out but will require a lot of people testing and some luck. A little more information is needed for me to be clear.
Look at her alleged birth mother. Can you find other people who have had their DNA tested that match to any common ancestors in this line? Can you track down descendants of the alleged birth mother and persuade them to test? If you find matches to this maternal line, what about the alleged grandfather's wife's line? Negative results are not very informative but they can help.
It should also be possible to see the difference in numbers, but this will require some luck and a lot of descendant testing to be sure. Though until I can be clear on the scenario it is hard to say what to look for.
If I read it right, the "also" in the original post meant that there was a suggestion that the great great grandfather had impregnated his own daughter.
If so, I don't see how looking at the poster's DNA could help with the query, especially given that this is now going back 3 and 4 generations. Identifying other descendants of the great great grandfather (not via the great grandmother) and comparing the amount of shared DNA could give an indication, but not with a high degree of confidence.
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Yes, it would impact on the amount of DNA shared with other matches who are from the same ancestral lines.
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DNA may help you with this. Could your father or any of his siblings take a DNA test?
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I have a theory that the father of my paternal grandmother might also have been her grandfather. Is it possible for me to be able to tell if this might be true from my DNA results? Please don't be too technical when trying to explain to me. I have to admit that I am still learning about how to use DNA results. Thanks for any help or advice.
In theory it is possible but in practice very unlikely to show anything significant.
I have been looking at DNA results of 5 daughters of one man where one daughter was claimed (by her mother, who had no reason to mention the subject to me (long story)) to be the daughter of his father (i.e. the grandfather of the other 4).
When their DNA is compared there is so little difference it is all within the margin of error and no conclusions can be made.
One thing is certain the daughter in question cannot have the same father as the other daughters as he was in prison at the time of conception, but even that could be in doubt if the birth was delayed.
Cheers
Guy
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In Guy's scenario though, that is the mother and the paternal grandfather conceiving. However, if the child was a product of incest between mother and maternal grandfather (i.e. her father), then surely that would skew the DNA results considerably?
https://genetics.thetech.org/ask-a-geneticist/identifying-incest-dna#:~:text=Look%20at%20Mom%20and%20Dad%27s%20DNA&text=We%20know%20that%20on%20average,their%20DNA%20with%20each%20parent.
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Yes I am suggesting that my grandmother's father might actually have been her mother's own father. I realise that this is not good and I am hoping that it isn't true but his wife would seem to have had dementia. Not sure at what age this started but the daughter (my gran's mum) never left home and stayed with her mum even when dad was away on business. Yet she managed to get pregnant twice. She was 44 when her father died and her mother had died 11 years previously. One week after he died she got married and moved out of the family home.
Now, I realise that I am putting two and two together and making twenty two but I thought it was a possibility and might be something worth checking before trying to work out who else it might have been. I understand that this was something which went on quite a lot back then - well, more than we actually think it did. It sounds as though it might be more difficult to prove than I had thought. My father is no longer with us and every one of his siblings have also passed. So I guess it back to the drawing board.
Thank you everyone for your replies and thoughts on the matter.
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Where did you test Towdlass? Has anyone more closely related to your paternal grandmother also tested, or your siblings and cousins, or any descendants of your gt-grandmother's siblings?
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Could the father of her children be the man she eventually married ?
You couldnt eliminate either theory unless you can find third or fourth cousins who connect to that lineage ..
I havent read the article but am guessing that descendants of an incestuous relationship would have a higher cm connection than predicted ones .
If that makes sense ie 3rd cousins could show up closer to 2nd cousin amounts
it would be interesting if anyone had examples of that
But they probably wouldn't want to share
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I did my DNA test with Ancestry. The nearest relative I have on my results list is my half cousin. She does share the same grand mother though and so this would affect her too. All the rest are related on my mothers side but only a couple of those. Mainly it's all 4th - 6th cousins. Does any of this help at all? The man my gt.gran eventually married was younger than her and would have been 11 and 14 when her children were born. One of the first things I checked because it would have been a nice closure to the situation.
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A half-first cousin is very useful for DNA - you share the same grandmother but have different grandfathers?
Have any descendants of your gt-grandmother's siblings, or her father's siblings tested? You may find that other relatives have tested at FamilyTreeDNA or MyHeritage, so you could upload there too.
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I really have no idea as I only know them through my family tree searching. I'll see what I can find out.
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My gran and her sister were both born out of wedlock. Her sister was born in 1879 and my gran on 6th Jan 1883. So I had a look at the 1881 census and made a list of all the men on that road of a possible age (some more possible than others it has to be said) I have been going through them one by one looking for any with matching DNA using Public Members trees on Ancestry. It's tedious but I thought it worth a try. However, I have had a hit but I'm not sure that it can be a DNA match for the reason I'm looking for. The match is only 7cMs across 1 segments. What do you think? If he was my great grandad it would be a higher number wouldn't it?
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7cm does seem small if your match is the same generation but would make sense if you were once or twice removed
I have a7cm proved match which goes back to 4 xgreat grandparents
But most at that amount are 6th cousins
Ps I admire your Detective work looking at names of all local men
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Thank you brigidmac I feel I deserve that pat on the back. It is so tedious, especially when there are no guarantees that it will bring forth an answer. I am now in touch with the lady who has this neighbour in her tree but don't know yet what relation he actually is to her. The 7cMs refers to the connection between she and I doesn't it? If he is a distant relative then I suppose that could be the reason why the cMs are so low? I find DNA quite difficult to get my head around, I must admit. One minute I think I've got it, I understand what it's about, but then I lose it again. Hey ho! ??? :o ;D
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When you say you are going through the names one.by one
Do you mean you are putting the Surnames into the DNA search filter.
It also shows if any of your matches with private trees have that name ...
It took me ages to work that out .
And that even if they.have unlinked trees you can sometimes. Find the names on there.
Good luck
Look forward to hear how you get on
Ps. Before dna test my mum looked at potential men for her mum's birth father turned out that one she'd discarded was his father .so when we had DNA and traced 3rd cousins or half 3rd cousins she had found a great grandfather as well as a grandfather . The ethnicity helped us too.
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No having looked at the 1881 census I had names and ages plus place of birth. So then I went on to Public Members Trees and put these details in, one at a time. The results for each one I looked at to see if they had had their DNA tested and if so was it matched to mine. As I say I have one match that I'm looking at with the help of the members tree I matched with. Watch this space. :)
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I have been working on the tree of the chap who I suspect might have been my great grandad and have found two more people with whom I share DNA. One has 16 cMs across 1 segment and the other only 6 cMs across 1 segment. Can someone please tell me if this is looking more likely that he is my grandfather or less likely. I do struggle to understand DNA but I would have thought that the figure would be higher??? Unless they are quite distant relatives of the chap in question? Am I understanding this right?????? ??? ??? ???
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Have you tried my tip of going to DNA matches and choosing search option with magnifying glass a symbol
put his surname in the appropriate box
Then you will see if there are any more DNA matches with.closed trees or unlinked trees
The more matches you have the more chance there is
Is it a common surname .?
I.recommend not ticking the alternative spellings box but.doing a separate search then
Other searches with location only
I'm going to play around with this to see what results come up to compare to your statistics
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Yes in fact my 19cm was. 3rd.cousin match but only surname.in common was our.mutual great grandfather
She was descended from his daughter's daughter so if we.hadnt traced our own.trees back.so.far we wouldn't have linked .
You could.add.the putative father tentatively to your tree ..with.a tag."hypotheses " this is controversial
Using location search.I come up with.some.20cm 3rd.cousins who I know come from my.grandgathers recomposed family so are actually half second.cousins thru his half siblings
So knowing the fact that the first cousins in your chain only share 1 grandparents you can expect smaller cm.in.future generations
I'm.watching this space .!
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I have started to add the details of the chap and a few of his closest relatives onto my tree in a tentative way in the hope that it might throw up something from ThruLines. I know I shouldn't really do that but to be honest people shouldn't take things they find on others trees as gospel without checking it for themselves, should they? I do look at other peoples finding for clues but always check their findings for myself.
Anyway, the lady I found first who has the connection of 7cMs says that she has no direct relationship to my chap but that his brother was the 2nd husband of her great aunt. So I think that would explain why the link is so small, don't you think? I don't know what else I can do to try to prove that he is my great grandad, do you? Though I do think that it is quite likely.
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I have to admit though that I am quite relieved that my original theory is proving to be wrong. :D
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Thru lines only show up if you have their descendants on your tree
+ Spell them the same
Some of my known matches don't show up because they've put their ancestors nicknames or shortened names
Shared matches is a better option
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Just to update you. I have re-read the email sent to me by my 7cMs match. The connection was via my chaps brother who was the 2nd husband of her 3 x great aunt. So very slender thread, eh?
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The DNA can't link thru marriage
So you'd have to trace your matches great grandparents and all their descendants .
Do the localities fit ?
Still admiring your persistance
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I went on to Ancestry DNA and put each surname I've generated so far into the search box for my results list. One of them brought up something good. One of the husbands surnames brought up a match of 2nd to 3rd Cousin with 270cMs. What do you reckon to that?????????
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That's fantastic ! Do they have a tree ?
Congratulations your persistance is paying off
You could have a grandparent or set of grandparents in common . depending if they are same generation as yourself .
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Yes they do have a tree but the name which brought them up is only one person on her tree from back in the 1700s so not sure if that will be our main connection. Seems unlikely. She and I have already been trying to locate where our connection can be for the last 18 months. I'm beginning to lose my impetus, I really am. I have more puzzles than you can shake a stick at. I've already managed to solve one but still have three more, including the current search. It is so difficult to keep going when you seem to hit so many dead ends. However, I'm not spent yet and shall keep going.
The thing is when you use the search box on the DNA results page it brings up everyone who has that surname in their tree but that can be a complete red herring. That's why I tried to do it the other way around and searched in Public Member Trees for the person you're investigating and then search the trees which have that person in them and look for someone who also has a DNA connection to me.
There may be other ways of searching and I am completely open to any help regarding this. At present it feels a bit like banging my head against a brick wall. Why don't more people take the DNA test? This could make my task so much easier. ;D
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Can one of you just clarify this for me please. The person I found who shares 7cM across 1 segment has the connection as being - the brother of the person I think might be my great grandfather was the second husband of her great aunt. Now, I know that's a lot to get your head around but what I don't have a clue of knowing is - would that connection give a result of 7cMs????? I don't understand DNA enough to be able to work out if it would or not.
I have been extending his tree in all directions but I can't seem to bring up anyone with a closer DNA match and my brain hurts. ???
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That doesn't sound right because the person wouldn't share any DNA with his aunt's husband unless they had a blood connection further up . 7 cm is very little
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Ah she did say that they had two daughters. I'm rather fuzzy about DNA Brigid. The 7cMs is the connection between me and her isn't it? So we could be cousins about 3 or 4 times removed????? If the chap I found brought her up as a DNA connection that must mean that the MAIN connection between him and me must be somewhere around there mustn't it? I feel like the proverbial blind man in the darkened room looking for something which I think might be there. I'm feeling totally bemused.
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I don't understand what you mean by " The chap who brought her up as a DNA connection "
Or who had 2 daughters
Maybe you could use initials when referring to your potential great grandfather + his brothers
It is hard to get your head around DNA
Have you asked your dna match if she has any matches which match you or your other DNA match ?
It's positive that you have more than one match from your unknown side .but 7cm could be from a known line just too small to show up .
I suggest giving DNA puzzle a rest for a while ..look at other people s stories and how they resolved them and come back to it when you have a few more matches
I'm working in my mum's link thought it was to a sister of her grandfather but think it might be a sister of her great great grandmother.thats a 28cm match !
+ They anglicised their names from Russian/ Yiddish so very hard to find
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Yes I think that you are right. I don't have very many close matches from my DNA results. I have only 3 in the hundreds and all the rest are 70cMs and less. So it's like knitting without much wool. It's years since I did my test though. I did hope that the lockdown would have prompted a few more to do a test. Oh well I think I will take your advice and give it a rest for a while. Thanks for your input over the last few weeks. Take care.
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It still hasn't arrived. When is the cut off point from being patient and waiting and getting in touch to complain it hasn't arrived? Last year it was possible to download certificates. It would have made sense to have brought that back again during the last few months.
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I'm taking a tip from your book and looking at names
For comparison have found a potential 2nd cousin with 32 cm 3 segments and several 6x cousins all born between 1980,-2000
Of 11-13cm descending from 3,daughters of potential great aunt
It really helps if you have a second family member test DNA +a wide range of generations
so you can eliminate random results
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I can't think who else I can ask. I shall put my thinking cap on. Would one of my children (not children any more of course) be ok or should it ne someone on my line ie. cousin?
I'm really pleased for you that you managed to find all that out. I've been watching a u-tube video about understanding cousins. I watch it and I'm understanding all that's being explained to me and he carries on and I'm with him all the way and then suddenly my brain just lets go of it. Like it's a step too far. I shall keep watching it in the hope that I will hopefully retain a little more each time I watch it. :-[
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Having a child test may be useful
Most of my close matches are approx half amount of CMS to my mum but occasionally distant matches have more CMS for me
But we're talking in range of 6cm- 15cm
But so distant probably 6th - ,8th cousins so wouldn't help your search that much .some of these matches are showing up because young people are testing .