Shared Matches v. Common Ancestors

[Gadget]

Hi

In Painter, 47cMs suggests a range of possibles with more or less equal probabilities, including a high incidence of 'removes'. Do you know the age of your match so that a remove is possible?


Gadget

[Gordon163]

Hi,

She was born about 1955, so 65ish.

How does the 'remove' idea work, please?

Gordon

[Gadget]

If your parents are ,say, second cousins with a match, then you would be second cousin once removed .

e.g

a   b 1st cousins
|    |
c    d 2nd cousins
|   
e  2nd cousin once removed  to d

[Gadget]

Here's a snip from Painter showing the difference in range between 2nd cousin and 2nd cousin once removed

PS this applies to all levels of cousinship and removes.

[Gadget]

As a statistician, you might be interested in this:

https://isogg.org/wiki/Cousin_statistics

[Gordon163]

Many thanks for this information - most interesting.

Gordon

[LizzieL]

A couple of days ago I had a new "Common Ancestor" match thrown up (person A).
Thrulines. She is not a new match as it is showing as previously viewed. She has not logged in for 3 - 11 months, so has not recently updated her tree.
I have not updated that branch of my tree for years and I misspelt the surname of the man who married my 4 x great grandfathers sister (who were her 4 x great grandparents).
I can only assume, someone else has added to their tree and in doing so provided our missing link.
I have checked her tree (9 people) and the interlinking trees and records they cited and cannot find any obvious faults, so I think she must really be my 6th cousin. Our shared matches are a first cousin once removed and a second cousin (daughter of the 1C1R) who are from the same line and should share the DNA of the same branch. So that all fits together nicely.
An unusual surname popping up in her line, led me to search trees for that name and location in all my DNA matches. One came up (Person P) who has a larger tree (908) and includes the name of my 4 x great grandfather's sister, so is also a 6th cousin of mine. He is a 3rd cousin of my first match. But he and I have no shared matches.
My match with A is at 13cM, with P it is 8cM. I know that shared matches have a cut off (20 possibly??), Shared Ancestor's don't, I have several with 6 and 7 cM matches. But I'm surprised that P has no shared match with my 1C1R and 2C.
This match has been significant because it is another bit of evidence to confirm my 4 x great grandfather and makes the couple who I think are my 5 x ggp more likely

[Flemming]

I know that shared matches have a cut off (20 possibly??), Shared Ancestor's don't

Is this bit true - that Ancestry will show matches lower than 8cM if you share a common ancestor with them?

[Gordon163]

I have a common ancestor with 6cm

Gordon