Find Brick Wall Ancestors: Son has 8; Each Parents has ZERO?

Question

Hi, My ancestor Speicher-385 has eight duplicate ancestors, using the tool here https://apps.wikitree.com/apps/nelson3486/brickwalls/ - the parents of the above-mentioned, Speicher-327 & Speicher-328, have zero each. Does this make sense? Maybe I am confused?

Answer 1

Hah that's weird. I'll have to poke around and see why.

Answer 2

Because Johann's parents were cousins (something like second cousins once removed), his mother and father had several ancestors in common. Those are the duplicate ancestors that this tool is showing you.

There are no duplicate ancestors within the mother's tree or the father's tree on WikiTree, so the tool isn't showing any duplicates in their individual trees. (But duplicates might exist -- there are a lot of blanks in their ancestries.)

Comments

Thank you, but would not Peter be a duplicate for both (these are Speicher-327 & Speicher-328), and therefore it would be one instead of zero for both?

 

Gertrud and Jakob are first cousins once removed

Gertrud Speicher and Jakob Speicher are both descendants of Peter Speicher.

1. Gertrud is the daughter of Philipp Speicher [unknown confidence] 
2. Philipp is the son of Peter Speicher [unknown confidence] 
This makes Peter the grandfather of Gertrud.

1. Jakob is the son of Johann Valentin Speicher [unknown confidence] 
2. Johann Valentin is the son of Leonhard Speicher [unknown confidence] 
3. Leonhard is the son of Peter Speicher [unknown confidence] 
This makes Peter the great grandfather of Jakob.

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Oh I think I got it now. If Peter was in either parent's tree twice, then it would be one dupe... Thanks.

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Lol Ellen, I wish I had seen your comment before I went analyzing my algorithm.

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When I saw the question I was perplexed and would have hoped for you to review the algorithm, but when I realized the issue was duplicated ancestors (not brickwall ancestors) and saw the duplicates names in the ancestry, all started to make sense.

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Thank you Ellen, he makes a good point and I panicked a moment until I read your response and remembered I'd already been thru this exact examination process when building my tree and discovered incidences of 2nd-4th cousins marrying. I even had a pair of cousins marry another pair of cousins or was it brother and sister marrying their own cousins. Something like that. This is a good tool but this genealogy stuff is funny and can mess with your head.... :)

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In recent days I researched a family (distant relatives of mine) where I found a severe case of cousin marriages and duplications of ancestors. To see how crazy this kind of duplication can be, check out https://www.wikitree.com/genealogy/Huntley-Family-Tree-1823

Jamie's tool says "Out of 2046 possible ancestors in 10 generations, 229 (11.19%) have WikiTree profiles.  164/229 (71.62%) are duplicates due to pedigree collapse."