4th-6th cousin surprises with 30-40 cm.matches

[brigidmac]

I like to think the DNA matches are quite logical mostly and 4th- 6 th cousin matches have helped me join dots in past ...as long as i can get at their trees.

I experiment a bit with shared matches to see if anything new shows up ..sometimes even if they have a closed tree their user name gives me hints that im on right track .

I suppose as matches get more distant the science gets less dependable but maybe someone can explain this

My dads sister  has a 3rd cousin from DNA
"Ann" shares same scottish  STEVENSON great grandparents
And matches as 3rd cousin on ancestry at 122 cm across 8 segments
So not surprisingly i come out as a 4th cousin ..ie 1 generation down
59cm shared across 6 segments with Ann.

So... i did a shared match test and found Gordon who comes up as 4th cousin to me 33cm shared .
His tree is open but only 1 surname in common so i cant work out relationship ..he does have some Scots from.lanarkshire

BUT for some reason he matches my aunt less than me at only 16cm across 3 segments .

I have  my fathers scottish blood so what could make the difference ?

Any theories or similar occurances ?

[brigidmac]

By the way i have no idea what number of segments refers to or implies .

If distant cousins marry will you get more segments matching from their descendants .its way over my head .i hope someone can explain in simple terms

[Craclyn]

Your Dad and your aunt will have inherited different DNA from the ancestors they share with Ann. If the cousin levels you mention are those taken from the ranges on Ancestry then you also need to take a look at potential relationships based on the cM level. A useful too for doing this is the Shared cM tool at DNA Painter. https://dnapainter.com/tools/sharedcmv4

[brigidmac]

Thanks cracyln
Im looking at.the table and tried putting 33cm in i dont.know where to add segment numbers

Im trying this on my phone maybe need to get to a computer screen to have a proper go .

When i work it out i.ll try it out on the matches we know.

Your explanation.is very clear thanks ..i understand that my dad and aunt would have different amounts but still wouldnt expect that i.d have double the amount she had ....does it mean  my father would have had 66cm ?

[Craclyn]

Don’t worry about the number of segments when you are trying to calculate the relationship. The shared cM tool only takes the size of the match, not how many segments.

[sugarfizzle]

To use DNA painter effectively, it is important to make sure the correct relationship is identified.

I may have misunderstood you, I think you are saying that your aunt and Ann have great grandparents in common, which would make them 2nd cousins, not 3rd, and you would be 2nd cousins once removed.

2G grandparents in common would be 3rd cousins, you would be 3rd cousins once removed, not 4th cousins.

Useful links -

http://www.cousincountry.com/site/cpage.asp?cpage_id=180010891&sec_id=180004334

http://www.cousincountry.com/home/180004334/180004334/Cousin%20Chart%20Snippet%202.jpg

As Craclyn says, the amount of DNA inherited by your father and his sister could be very different. At this level, your aunt might have inherited none at all from these particular ancestors.

A great benefit of having a close relative testing as well as you, especially if you have access to their matches, is that you get a wider picture.

Regards Margaret

[brigidmac]

Thanks sugar fizzle
Yes its great that i can check my aunts matches too.

I think id assumed from what she told me that Anns  gran."Mary BLAiR Stevenson was named after her grandmother like my grandmother Mary( Polly) BLAIN STEVENSON and it was another  example of a cousin with.a slightly different spelling .

But when she told me about order of birth and name of her great aunt I realised that her gran was youngest daughter of The original Mary McBLAIN/ BLANE/ BLAINE (named after her mother ...1st daughter was  amed after William Walker STeVENSON .s mother Euphemia RAMSEY no evidence so far of an earlier daughter named after Isabella Clyde ...Mary McBLANE s mother .
Ann s gran married Alexander Barton ROBERTSON and emigrated to Canada but came back in recession .now her grandchildren live in Australia

The ancestry definition gives 3rd cousin.but the thru lines says 2nd cousin.

So 
William Walker STEVENSON b1851 and Mary BLAIN  are  :
 parents to Mary BLAIR STEVENSON Anns gran
 
Gparents of
 my gran Polly MARY BLAIN STEVENSON B 1903

 great Grandparents to my aunt Mary and Ann

& great grandparents to me

The DNA summary indicates 3rd cousins but thru lines correctly has 2nd cousins for aunt Mary and Ann

So i am 2nd cousin once removed .

Bonus
 Ann now knows who her great grandparents were
I know more about their life in Scotland and Canada  the theory that  STEVENSON women live to their 90.s
Upheld by our mutual grandmas and their sisters

And Aunt Mary will learn she has 3... 2nd cousins in Australia

 i havent used the painter chart yet .

[brigidmac]

Now to look at some of those "4th " cousin matches with gordon and other 30+ cm matches
 
It goes to show that matches are sometimes closer than you think .several of my mothers "3rd cousins were actually half 2nd cousins or generations  removed because paternal  grandparents both had first marriages  and maternal grandmother had another family .

Another advantage of having tests from older generation is that you can see known links across you ger generations and it helps speculate links with ancestors.

[sugarfizzle]

Thanks sugar fizzle

The ancestry definition gives 3rd cousin.but the thru lines says 2nd cousin.

Worth remembering that it is only an estimate that ancestry gives, not a definition.

I have several matches descending from one couple, my 2G grandparents, the same number of generations, that is, we are all 3rd cousins.

My highest match is 153 cMs, the only one predicted to be a 3rd cousin. The lowest match is 17 cMs, predicted to be 5th to 8th cousin.  There is another one at 19 cMs.

Daughters of the 153 cMs show as 28 cMs and 27 cMs, even though they are a generation later, 3rd cousins once removed.

It's a lottery how much you inherit from each ancestor.

Regards Margaret