And why would you want to know that? I don’t see how that information helps anyone except for someone trying to figure out the origin of an obscure disease/mutation.

This exists already, GEDmatch can run an analysis using raw data and tell you if your parents are related. No, my parents were not related
Far back I don’t think there is a way to tell or even that it really makes any difference.

@zenvelo someone posted a pic of some hillbillys, and I wonder how far back if ever my bloodline looked like these inbred meth heads….

My great grandmother married her father’s cousin. I know this through genealogical research, and through my great grandmother, who did her best to cover it up.
We did a DNA test, and there was no indication that something like this was detected.
Looking at the science, I doubt this could be done.

My response is in the whiny room.

You will need to have the DNA of many family members analyzed to get a useful answer to this question. I used to work in medical genetics.

I wouldn’t care at all if back in my lineage cousins made an ancestor of mine. Friends of mine are married first cousins. I would hate to know a father raped his daughter and that resulted in a pregnancy, but if it’s 8 generations back I can’t do anything about it.

I would only have to go back to my paternal grandparents. They were second cousins (or something like that) and didn’t know it until after they had been married a few years.