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HarrysMum
02-03-22, 06:36
If you have 8% cM and less than 1% shared DNA……..5th to 8th cousin, are you always related? Or can some DNA be shared by people who are not related until they get back to Adam and Eve?
Phoenix
02-03-22, 07:27
An 8th cousin argues an ancestor born probably c 1700 or even much earlier. Potentially over 500 ancestors in that generation. I doubt that even the Queen could name every single one of her ancestors that far back. So I don't think you could argue you are NOT related to somebody, simply because you can't find the link.
HarrysMum
02-03-22, 09:24
An 8th cousin argues an ancestor born probably c 1700 or even much earlier. Potentially over 500 ancestors in that generation. I doubt that even the Queen could name every single one of her ancestors that far back. So I don't think you could argue you are NOT related to somebody, simply because you can't find the link.

Maybe I didn’t word that question well…… I’m more wondering if there could be others out there who have that much of the same DNA but are not related.
I was reading about this research into genetics where the researchers found people who were quite close genetically but they could not find any family relationship. One was a very English lady in Devon who was very fair in colouring, tiny, sweet lady. Genetically close was an Australian Aboriginal man. Once again completely different in appearance and background.
I suppose I’m a bit annoyed at having so many of these people in my DNA matches and they have no trees……so no way of connecting us. They also do not answer messages.
kiterunner
02-03-22, 09:39
Surely the Australian Aboriginal man could have a bit of DNA from a white ancestor?
Phoenix
02-03-22, 09:54
If a gene mutates randomly, then there has to be the possibility that two people will have bits of identical DNA which they have acquired independently. What I don't know is how many cM the DNA has to be before you cannot put it down to chance, but must accept a relationship.
maggie_4_7
02-03-22, 12:36
Surely the Australian Aboriginal man could have a bit of DNA from a white ancestor?

Indeed especially with the amount of transported convicts. I expect if the lady traces her ancestors back there's a convict in there somewhere.

I have found another two, siblings of a direct ancestor.
HarrysMum
07-03-22, 21:19
I guess my question is more…….could anyone get 8cM and less than 1% shared DNA with a person not related or related so far back, as in the Stone Age?
kiterunner
07-03-22, 21:48
You might like to read this, Libby:

https://lianejensenresearch.com/2017/02/22/how-to-tell-when-dna-matches-might-be-false-positives/
HarrysMum
08-03-22, 00:23
Thank you. That answers my question. I have a few of 8cM and a couple cannot find any connection. I know there could be the unknown adoption, surprise baby, but I also think some are not really related to me, just randoms.
Kit
09-03-22, 00:43
Blaine is really knowledgeable, he has an FB group and he is also very lovely. That article explains what I was badly trying to work out how to say in my head.

Mind you do look at the ones with trees. I have a 7cm match and assuming her tree is accurate (I haven't looked closely but have no reason to doubt at this point) we match on a single 5g grandmother only. She married 3 times and we descend from different husbands. I should look into that more now I know a bit more about DNA but it was exciting to pinpoint 1 exact relative that we match on.