Puzzling DNA results

[Mary from Italy]

I have a couple of lines where DNA results have thrown up enormous problems.
This is the first one.

I have a female cousin (F), who is my 3rd cousin on paper. Her great-grandfather Thomas Mallet was the brother of my great-grandmother Caroline Matilda Mallet. We have a 16 cM match on MyHeritage. That was a bit smaller than I expected, but I realise DNA is variable.

I also have a male cousin (M), who on paper is the 4th cousin once removed of both me and F. His 2xG-grandfather Henry Mallet was the brother of John Mallet, Thomas and Caroline's grandfather.

M recently tested with MyHeritage, and the results were a bit of a blow. He has a 40 cM match with F, but no match with me!

This is the branch of my tree that I knew most about when I started: I have the family bible, with names and dates.

Before I post the full details, which are quite complicated, I wonder if anyone can answer what is probably a silly question.

I tested with Ancestry, and then uploaded my results to MyHeritage, whereas F and M tested directly with MyHeritage.

Could this have made a difference to the results?

I've noticed that MyH tends to give larger cM numbers than Ancestry for the same test, but I wouldn't have thought that testing with two different sites would cause an entirely false negative result.

[kiterunner]

Once you are further removed than 2nd cousins, there is a chance of no DNA match at all. So you will have to take the fact that M is a match to F and F is a match to you as enough proof.

I don't think that uploading from Ancestry to MyHeritage makes a difference.

[Mary from Italy]

Once you are further removed than 2nd cousins, there is a chance of no DNA match at all. So you will have to take the fact that M is a match to F and F is a match to you as enough proof.

Ah, OK, thanks.

In that case it probably isn't worth posting the full details.

What worried me is that although I have my great-grandmother Caroline Mallet's date of birth in the family bible, and I've found her baptism with the right parents, there's no sign of a birth registration (although she was the 4th of 5 children and the births of all the others were registered), so I was beginning to wonder if she was the illegitimate child either of her mother Matilda or her mother's spinster sister Caroline.

That would explain why I matched with F but not M, but that theory seems to be disproved by the fact that I have DNA matches with descendants of several relatives of John Mallet's wife Mary Ann Bentley, and the only way I can be related to Mary Ann is through her son Thomas Mallet, the father of Caroline Matilda and her brother Thomas.

I don't think that uploading from Ancestry to MyHeritage makes a difference.

OK, thanks for the confirmation.

[Phoenix]

I am starting wonder what value DNA results actually are, except to the commercial companies. I attended a zoom lecture on Saturday, where the speaker said exactly what Kite has said.

The trouble is that I am really not interested in close relationships. The lines that interest me are pre-census, which takes them outside the scope of reliable DNA matches. I have one or two where I am related to 4th grandparents via 3 or 4 children's descendants matches, but that is vanishingly rare. (and they are within the scope of censuses)

[Mary from Italy]

The trouble is that I am really not interested in close relationships. The lines that interest me are pre-census, which takes them outside the scope of reliable DNA matches.

Same here, which is why I have a few ongoing problems.

I have some lines where there's an abundance of DNA evidence but a tenuous paper trail, and some with a very good paper trail and little or no DNA evidence.

[Mary from Italy]

I was still a bit worried about my wretched Mallets, because there are another couple of people on Ancestry that I should have a match with but don't; however, right on cue a new match has just come through (a descendant of Henry Mallet's uncle James) that definitely confirms my Mallet connection, so that's a great relief. i don't even need to check out his tree, because I already had his grandfather and ancestors on my tree.

I probably wouldn't even have noticed the match, as it's only 8 cM, except that Ancestry did the Thrulines thing. Luckily I check my unread Common Ancestors occasionally.

I was initially sceptical about Thrulines, because it's presumably entirely automated, but I've found it extremely helpful on several occasions.

[Kit]

Don't give up on distant matches.

I have a match for a 5th g grandma. She married 3 times and we are descended down different lines so the only relationship is that 5g grandma.

[Mary from Italy]

Oh, I agree, I have some really good small matches like that.

[marquette]

I am starting wonder what value DNA results actually are, except to the commercial companies. I attended a zoom lecture on Saturday, where the speaker said exactly what Kite has said.

The trouble is that I am really not interested in close relationships. The lines that interest me are pre-census, which takes them outside the scope of reliable DNA matches. I have one or two where I am related to 4th grandparents via 3 or 4 children's descendants matches, but that is vanishingly rare. (and they are within the scope of censuses)


I am the same, its nice to find the close relationships, but I am looking for DNA matches to my Dads 3g grandmothers and grandfathers as the parish records are missing or useless.

However, small DNA matches with good family trees from several people show me that my choice to research a particular family seems to be correct as Ancestry is showing up common ancestors.

I have a couple of anomalies - like my daughter who has a match to a man whose family tree matches up with ours, but he has no DNA match to her grandfather. And a common ancestor is suggested by Ancestry for one of Dad's 3g grandfathers, but they don't have a good enough tree and I don't think the dates match up very well.

I am always surprised that even 5cM of common DNA is so distinctive among people who have 5xg (or greater) grandparents in common.