Is Unknown father also a match.

[Sinann]

I was recently given access to my 1st cousin's DNA on Ancestry, I have my own and my sister's.

Looking at my 1st Cousin's matches on her mother's side I am really starting to understand the difficulties some people face with low cMs, and lack of trees, I've only confirmed one DNA match on her mother's side.

There is one match in particular on her mother's side I'm trying to get my head around that I'd love your opinions on.

1st C and DK share 338cM
1st C and AP share 100cM
DK and AP share a common ancestor ER.
ER is DK's grandmother via her daughter E
ER is AP's great grandmother via the same daughter E
BUT the daughter E had first child with Unknown father, (DK's mother)
than married and had another daughter AP's grandmother.

It seems clear enough that 1st C is some how related to ER BUT
AP is also a match on 1st C father's side, to me at 37cM and my sister at 13 cM
I can trace this connection, we all share great great grandparents.

Am I right in thinking that AP's 100cM would be divided (probably unevenly) between both sides and given she is only one generation further down the line than DK at 338cM than 1st C could be related to both DK's mother E and Unknown father?

[brigidmac]

i.ll take a look at this when my head is clearer .
have lots of examples from recomposed marriages to compare to

+ have a man who married his deceased wifes neice had children with both 1870-early 1900

which is the kind of thing that can skew calculations

im sure dna experts will copy links to the charts and steps for you to unravel

pm me if you want personalised tutorial

B

[Biggles50]

With any DNA match I like to key in the cM value into DNA Painter are look at the percentage probabilities.

Among them for the 338cM are 1/2 1C or 1C1R both @ 49%
OR
2C or 1/2 1C1R or 1C2R both @ 46%

So these give a good idea of where the link occurs which is probably at or since Great Grandparent level.

As a rough guide, my 100cM ish matches tend to by 3C.

Beyond that, below 50cM they can be anywhere from 4C to 7C, its so imprecise and hence needle in haystack.

Also if the families concerned are from a close community then there can easily be Cousins marrying Cousins, so what I term Cross Pollination between the tree branches can very easily have occurred which in tern will screw with any assumptions.  ie In one tree I made for a family friend I found that one Grandparent pair were 2C to each other.

DNA division is not necessarily equal, so do bear this in mind in assumption made.

You could always create a family tree to put into DNA Painters WATO tool to see the hypothesis that it suggests.

[Sinann]

Thank you. I'm not having any luck finding 1st C connection to ER, lack of records isn't helping so looks like I can't even get over the first step at the moment but I haven't given up still a few more irons in the fire.

[brigidmac]

It's most likely to be the generation before what's coming out as first cousin level will be half second cousin look to see it the great grandparents had a first and second marriage

I haven't checked from says but the person I'm helping now is having hard time getting his head around the DNA indicating first cousin match when it could also be half uncle or first second cousin
Age of thetestres not significant could be a child of unwed single woman brought up by grandparents

Do check dna painter cager for all scenarios