DNA Testing and unknown Great Grandfather

[Montes]

From the paper trail, all of my ancestors are South Western English & Western Scottish.

I have one unknown great grandfather, who is rumoured to have been american.

I got an ancestry dna test done. I came back as 89% British, 9% German and 2% Eastern European.

Do you think it is possible that this 11% non british ancestry is my great grandfather? It would make sense, as there were lots of germans in the Americas

It's possible but I really wouldn't put much store in the ethnicity estimates which are notoriously inaccurate.

What you really need to start doing is working through your matches on Ancestry - ignore the ethnicity. Start with the closest matches, those which have the most centimorgans in common with you. Look at their trees, work out whether they are mother's side or father's side and tag them accordingly. If you then start to come up against people who you can't fit in anywhere, contact them and ask them to share information.

It’s possible but it’s quite a tenuous link. Have you got your grandparents birth certificate and checked census records the traditional way? Or was it a war time fling or something?

Have you looked at the parental inheritance thing on ancestry? It’s also on 23andme. You could also use thrulines or look at the map of matches and examine the US ones one by one. Are they clustered in any particular area? Testing on 23andme lets you search relatives by community eg German

Oops sorry, it’s myheritage that has that genetic community search thing, Germans in Midwest etc if you mean American as in US - you could probably expect to have matches in those communities but it might be coincidental.

The other thing I’d say is that the German on ancestry covers a wide area. I should be 50% Dutch but instead it’s a mixture of German and Scando countries so your ancestor may be say Dutch, Austrian, Czech or something else entirely.

Like other posters have said go through the ancestry DNA matches and colour code them or sort in some way so you can figure out who belongs to which ancestor.

I would suggest you read about and then try, the Dana Leeds colour clustering method, as this might help you separate out your lines better and help make it clearer where you need to concentrate your efforts.

Leeds Method

11% could be the right sort of amount from a great grandparent (average would be 12.5%) but it's random what you inherit - nearly 50% of my DNA comes from the exact place in Ireland my paternal grandmother was from, so seemingly I got most of her DNA from my dad with very little from his father. So your German/European blood could be from further back.

Do you have a tree uploaded to Ancestry? You need one that is as thorough as possible for all the lines you do know, then you can look at your cousin matches who have trees and you should find a cluster who match you and each other, but nobody in your tree. They should all have an ancestor in common who could be your gt grandfather if you're lucky or it could be one of his own ancestors - the amount of DNA you share would help you work it out.

Also you can look at Thrulines for potential ancestors and check regularly for ancestors with new DNA matches, last names might have been anglicised over time (Wachs to Wax, Muhleisen to Milliron etc)

The 2 % Eastern European is a tiny amount and could come from many generations back. If you tested on Ancestry they now show you if the EE and German are inherited from the same parent. If the 9% German came from 1 parent, I would use the Leeds method of clustering your DNA matches.

Apart from the indigenous Native Americans, every American is an immigrant, or descended from one. So this sort of test will pick up country of origin, not their nationality.