My wife and I both have Scottish ancestry. Turns out there’s a chance a clan I descended from may have nearly genocided a clan she descended from, and if they had completed the job back in the day there’s a good chance she wouldn’t have been born. A few from her clan were let go to spread the word to others to not fuck around, and she’s descended from one of them.

Mitochondrial Eve

Lol, that actually sounds like fun to investigate, and i'm a bit jealous. My SO and I both have family that lived in rural Arkansas up until the early-to-mid 1900s. We stopped asking questions after we discovered that because we don't want to end up having to ask how close is too close. We're definitely not 2nd cousins or anything, and it's doubtful that our respective "rural Arkansas" is the same place. But my grandfather was an orphan, so that side of the family tree is particularly murky...

Oh! Only tangentially related, but I have a second cousin out in Alabama who married her step-brother. They didn't become step-siblings until they were in their late teens, so it's not like they grew up together (well, not anymore so than kids the same age in a small town), but still... Roll Tide.