Making sense of 2nd 3rd .4 th cousins when ancestors remarry or unmarried

[brigidmac]

I.m working out links and knowledge and facts link up exactly so far

Ancestry result.
1st cousin  yes she shares both gparents

2nd cousin is child of someone who shares these gparents

3rd cousins two people who share great grandfather

Then I have two 4th cousins who share a great grandfather with me.... different g gmother

 1)  why would the son of one of these come up as a closer match ..          ..3rd cousin ? 

2) if someone has  1 grandparent in common with me will .... they show up as second cousin

I have a second cousin match with no common names on tree

could it be half sibling of my unknown grandmother .. unfortunately the match hasn't answered my message
 #. Oops I meant child of gmother ....my mother's half sibling

[familydar]

Are you talking DNA testing?

Jane :-)

[brigidmac]

Yes those results were from ancestry DNA test ...

Though i.m also interested in how you term relationship ...if someone shares granparent even if the other grandparent is from a different marriage or unmarried relationship ..i.d still call them my cousin !

[familydar]

I'd apply the same rule as you regarding cousins.  It's quite common for people to have two families by different partners - nowadays often through divorce and remarriage but in the old days it was because a man needed a wife to look after a brood of young children, if their mother had died in childbirth for instance, or a young widow needed a financial provider.  I'd expect the children of the half-siblings to regard each other as first cousins.  But bear in mind that on census forms "cousin", "aunt", "uncle" and "-in-law" were sometimes used in ways we wouldn't expect, you need to keep an open mind.

Genetically if only one grandparent is shared between DNA matches the match will look like a 2nd cousin rather than a 1st cousin, with the principle carried on down through 2nd, 3rd, 4th etc cousins.  But if through the generations the amount of DNA inherited was slightly more from one side than the other, it's easily possible for someone to have significantly more or less of one particular GGF's DNA than of the other seven GGPs and this could skew the results.  If I'm reading your post correctly you have a closer DNA match with the son of what you are calling a 4th cousin than you have with that 4th cousin him/herself.  I would say you're either looking at a double relationship - through the son's other parent - or it's coincidence.  If you upload your DNA results to GEDMatch and to FTDNA there are all sorts of tools you can play with and you might get extra matches which will help clarify things.

I can't fault your logic that someone sharing just one of your grandparents will be considered by Ancestry DNA to be a 2nd cousin, but rather than that person being a half-sibling of your unknown GM I'd say they are more likely to be the direct descendant of that GM, or indeed of your GF (he might have fathered a child outside marriage and the mother kept his identity secret).  It's a shame the match hasn't responded to your contact but it's possible he/she is an adoptee and thanks to you has found out who they are, but feels under no obligation to reciprocate the favour.

There are lots of very knowledgeable people who haunt RC's DNA board, you might want to ask the mods to move your post.

Jane :-)

[brigidmac]

Thanks so much 

You confirmed my hypothesis

sorry I got confused at end cos it's my mum's test and thought clearer to write from her point of view * have added ps to that script

I posted this topic on DNA board because I thought that's where I'd get best advice
Where do you suggest I move it to ??

I want to upload my results but don't know anything about Ged  files
I'm hoping someone technological will talk me thru it step by step ie not from written instructions but I will make an attempt to follow the instructions on the site

If I don't reply in the next few days i.ll be lost in cyberspace . 

[familydar]

sorry brigidmac this is indeed the DNA board   Having a senior moment 

[brigidmac]

Haha yes I did wonder if you thought it was on common room page

I'm following download instructions

I wonder if I could already have viewed raw data  didn't realise I had to download it .

It's a bit scarry ..says "do not close browser" and press only once !

What if  I accidentally pressed twice

How long should it take

[brigidmac]

Panic .....screen on smartphone has gone back to saying download DNA raw data
Rang the helpline..can't download to smartphones so have done it to my computer next challenge will be to retrieve it from computer and put it on the other place you mentioned

[brigidmac]

our DNA tests : the unknown second cousin is indeed son of grandma's half brother

I have linked others this way too by comparing how the people with one  known grandparent in common
 or and great grandparent show up on test and then try to guess how others may be related

So far American  4th cousins bear out this hypothesis
My  previously  unknown "4 th "cousin shares a great-grandfather ..and has shared a picture of him !
But for some reason her nephew come out as a closer link ..3 rd cousin ...I wonder if further up his line some cousins married so he has more of them" FELLMAN" blood

A 5th cousin of Jones  is somehow related to my Roberts line ..by tracing all of both our great great great grandparents children we may find the connection .common names are hard to research

Location and maps are important
Wales  is not enough ..if you can pinpoint a village of origin it helps

I found some of her Jones on 1850 census were carpenters which matches profession of my great great  grandfather    And 1 son

order of children's births helps identify same family across the years

 a few more original first names would help

Making progress