Any German-DNA Australian truckers in your family tree? and other DNA frustrations

Question

I have a couple different issues here.

I have taken my DNA test on FamilyTreeDNA and added on GedMatch. I have a slew of  3rd to 5th and 4th to distant cousin matches who are Australian/New Zealanders and whose family tree is Australian/New Zealand until you get back to English/Scottish ancestors who immigrated there many generations back. I know a good bit about my more recent ancestors and am sure that from my great-grandparents down that no-one has been there expect my grandmother when she was well past having children. I know my 2% English DNA which doesn't line up with their's and 94% of the rest is likely German/West European. (4% came up as not statistically significant split between Finland and what has to be my Polish Robaskievicz DNA)
In fact, my first brick wall is my great-great-grandfather who was supposed to be a trucker that knocked up my great-great-grandmother. She was unwed and gave the baby to her married sister and her husband. Most of my searching is hoping to find out more about him. (The baby- my great-grandmother, is the profile I added below. She was given her uncle's surname Green at birth. Her aunts and mother's maiden name should be Lisk)

I also have a ton what are supposed to be 2-4th cousins and 3-5th cousins who I can only find a link 10 generations back. I do have one that I've found three different branches with links to- 10th cousins, 11th twice removed and I forget the third way. The DNA chunk should be too large to just be tiny bits from 10th-great-grandparents added together though.

I know my DNA didn't get swapped at the lab because I do have matches with known relatives. So either that trucker really got around, or somethings not adding up right.

So does anyone have any German-DNA Australian truckers in your family tree? Or similar problems with matches?

Comments

No GDNAATs in my tree, but I've experienced the cousin-matching issue.  The DNA algorithms seem consistently to underestimate the distance to my Acadian cousins.  If they predict 4-5th cousin, it almost always turns out to be at least 6-8th.  Still, I think it would be interesting to run down 8) one of those truckers and see how the connection works.

---

Populations like the Acadians/Cajuns have a small gene pool, and you will likely share many ancestors with any other Acadian/Cajun person. That's likely why you're 6th and 8th cousins are appearing as 4th and 5th cousins. This is not the case for every ethnic group.

---

From my brick wall page : Out of 2046 possible ancestors in 10 generations, 378 (18.48%) have WikiTree profiles.
2/378 (0.53%) are duplicates due to pedigree collapse.
124 ancestors are missing at least one parent:

I don't think that's a high amount of pedigree collapse? It's really bothering me that I have what statistically should be closer matches due to DNA size. For instance, one match says I share 52 centigrams, with 11 being the largest block and that he should be fourth cousin- our only link is 11 generations back and his tree is more complete than mine. I lost the page he sent me on how much DNA to expect from how close of relationships.

I woke up in the middle of the night last night and couldn't go back to sleep until I started a matrix spreadsheet of Australian relatives and whether they matched each other and other matches. Its going to take a while to re-sort whose Australian though. 

Thankfully my dad finally decided to do DNA, so I'll hopefully be able to triangulate some stuff a little better.

---

I think that's a small amount of pedigree collapse.  But the stats and percentages only apply to the ancestors you know about.  72% of your tree is terra incognita.  When I see really large discrepancies between the predicted distance and the closest link I can find (like you describe), I suspect there might be a closer link behind one of those brick walls.