This is the third post regarding anomalies in our family tree. I discovered that my 3rd Great Grandmother, Sarah Ann Fleming, had parents that were first(!) cousins to each other. In the tree segment below, you may notice a bunch of “Fleming” surnames. The Fleming Clan (literally, a clan) originated in Scotland in the 14/1500’s; our branch of the clan settled into what is now West Virginia.
Looking at the family tree segment you will see Sarah Ann linked to her parents Alexander and Mary Eliza Fleming, my 4th great grandparents. In the next column to the right you can see more Flemings; the names of interest here are Mary and Nathan Fleming who were brother and sister. Their parents were William Fleming and Jane Frame who appear at my 6th Grandparent level twice. Of note, Alexander Fleming at top right was a Fleming, but only distantly related to William; as a consequence of this distance, Matthew Fleming who married Mary Fleming, was probably only her distant cousin.
I asked ChatGPT how many ancestors a person has – this is the answer I got:
The number of ancestors a person has depends on how far back in their family tree you’re considering and whether there is any overlap due to shared ancestors. Each generation back doubles the number of ancestors because each person has two parents, four grandparents, eight great-grandparents, and so on.
For example:
- You have 2 parents.
- You have 4 grandparents.
- You have 8 great-grandparents.
- You have 16 great-great-grandparents.
So, if you go back 10 generations, you would theoretically have 2^10 = 1,024 direct ancestors. However, this is a simplified model because it doesn’t account for intermarriages or instances where distant relatives are common to multiple lines of descent, which can reduce the actual number of unique ancestors. Additionally, for practical reasons, tracing back all lineages accurately for many generations is often impossible due to missing records or incomplete genealogical data
There was no mention of the fact that if you go back in the progression 2^x that eventually the number would exceed the entire population of the planet. That’s an interesting concept.