by jimwalton » Thu May 23, 2019 3:31 pm
> how did all humans become so genetically different from one another?
No one really knows the origins of humanity's racial differences. It is thought, obviously, that the various racial traits evolved, but tracing that all down has proved, so far, to be unproductive.
Geneticists tell us that if we trace everyone's genetic line backwards, there are a few points of convergence (TMRCA values) in biological history (people to whom we are ALL related: are universal genealogical ancestors but not universal biological ancestors). One would be a couple about 8000-10,000 years ago (Swamidass hypothesis), and the next would be a couple about 750,000 years ago. Interesting that we all, despite our racial differences, trace back to a common line somewhere along the genetic thread. After the event about 8000 yrs ago, however, there was an immediate, exponential population growth.
> What was Adam and Eve's skin color in your opinion?
There's no way to know the answer to this question. It's pure speculation to guess at it, and not a worthwhile pursuit.
> They look white in all the human representations, but then how could millions of their descendants end up being very black-skinned, for example?
Don't go by the representations of European artists. That's not to be considered to be authoritative about their appearance.