system
A chat on subreddit /r/NoStupidQuestions
human
That doesn't make since because the whole family would keep reproducing with each other with no out side DNA coming in. The human race would not have survived.
gpt
The human genome is large and complex enough that the original humans could have had the genetic potential to account for all of the races we see today. 

Quite a bit of our diversity now is adaptation anyway, so I don't see this being that much of a problem.