What does common ancestor mean

[Creasegirl]

I just got my dna results back and a bit confused as my mums 1st cousin who I know and has also had her dna done is not shown as a common ancestor wth me but a 1st or 2nd cousin. Her father was my grandfathers brother so not sure why that wouldnt be a direct ancestor.

There is also a 2nd or 3rd cousin that we cant find any direct links to and has read both our messages but not replied.  How could they be so closely related but noone knows who they are.

Hope you can help me.

[Gadget]

A direct ancestor is a parent, grandparent, great grandparent, etc. so she would not be a direct ancestor .

Your mother's  1st cousin would be your 1st cousin 1 removed.  The cousin and your mother would share grandparents who would be your direct ancestor (grt grandparents)

Gadget

[Gadget]

Family structure is the basic of genealogy - see for example:

https://www.quora.com/What-are-direct-ancestors

[Creasegirl]

Thanks but I am still confused a bit.

I have a 3rd cousin who is showing as a common ancestor and we share a 2nd great grandfather.  There are also lots of 2nd cousins 1 removed who also show as common ancestors.

[clayton bradley]

If they don't appear under the heading "common ancestor" it can be that there is something different about your tree and theirs and Ancestry's algorithm is not picking up the connection. Maybe somebody has spelled a surname in a different way. Also, if one of you hasn't linked their tree Ancestry can't link you up however clear the relationship.

[Pheno]

I think you are misunderstanding the Ancestry report.

A common ancestor indicates, that from the use of other trees Ancestry can ascertain that you have an ancestor in common, a direct ancestor to each of you.

If you click on the match, on the left hand side of the resulting screen will be the names of the common ancestor.  Underneath will be a link, which if you click on it, will show you the relationship that Ancestry thinks there is between you, descending from the common ancestor.

Be warned - do not take these as totally correct.  The descendancy is only as good as the Ancestry trees from which the info is taken.

Hope that helps, Pheno

[Gadget]

Thanks but I am still confused a bit.

I have a 3rd cousin who is showing as a common ancestor and we share a 2nd great grandfather.  There are also lots of 2nd cousins 1 removed who also show as common ancestors.

As the others have said, it's because the common ancestor is  not in the other person's online tree and cannot be ascertained from other sources.  Neither my niece or a few other close relatives are shown in my Common Ancestors listing as she and they have put up a tree from other lines. 

[Creasegirl]

Thanks for all the replies.

I take it though that the dna is correct even if the people haven't done trees so wouldnt pick up a common ancestor from the tree that way.

[Gadget]

I take it though that the dna is correct even if the people haven't done trees so wouldnt pick up a common ancestor from the tree that way.

Yes. My niece shares 1846 cMs with me and her children share 1100 cMs and 836 cMs with me. Also, a  second cousin shares 340 cMs with me. All are proven links but none are classified as sharing  Common Ancestors by Ancestry.  A first cousin shares 603 cMs with me. He is in my  Common Ancestors list as he has a tree which shows our common grandparents and our fathers .