You were suggesting in your original post that Muhammad is the ancestor of everyone on Earth, basically. That implies that everyone else who lived in his time was a genetic dead end.

I replied to your post that everyone on earth in 10,000 years will be the descendents of just a handfull of people alive today.

Do you see the similarity in these statements? You basically made a Darwinian conjecture, that nature selected Muhammad's descendents to dominate the earth (which I think is BS). What are your reasons for believing Muhammad is the ancestor of everybody? Why not Joe Blow who lived next door to him?