I'm sure you've heard of the alternative theory. Adam and Eve contained random genes. All that was necessary for the human race to enjoy variety. In this theory, Adam and Eve could not predict what their next offspring would look like. It would be Oriental or Oriental with a tan complexion. When the races became solidified, in that the parents are forced to accept children that look exactly like themselves is a consequence of degeneration, and yes perhaps a form of de-evolution?

See

• DNA Shows One Mother Of The Human Species
• Changes In Human Traits That We Can Observe
  • Changes To Physical Appearance At Babel
• Babel And Linguistics