Posted by:
Lot's Wife
(
)
Date: July 03, 2023 07:45PM
You and Dave are exploring different questions.
His analysis is what I presented in this thread:
https://www.exmormon.org/phorum/read.php?2,2473611,2473648#msg-2473648It's standard stuff but does not purport to distinguish unique ancestors from potential ancestors. In short everyone's family tree has a number of redundancies that expands exponentially as you increase the number of generations.
That's why virtually all Western Europeans are directly descended from William the Conqueror, Charlemagne, and almost all other famous people from long ago not once but dozens if not scores of times. And if some interloper from abroad, be it the occasional Othello or Chinggis Khan or Attila the Hun, managed to reproduce with Westerners several times, a few centuries later his DNA would have entered the common pool and eventually have touched almost all European family trees.
To take the argument to its extreme, there were points in early hominid history at which environmental factors reduced entire HSS populations to just a couple of hundred individuals regionally or globally. There are accordingly episodes whose survivors number among the ancestors of all of us not through one or ten lineages but through tens of thousands of them.
So yes, any of our trees would inevitably have a very large number of redundancies.