There's a pretty old hypothesis that explains the lack of genetic variation in humans: "And God created man in His own image, in the image of God He created him; male and female He created them." The more we learn the more we see evolutionist assumptions refuted by real science.
Actually, you missed a better parallel... That of the Flood.
I posted a thread on the "We Dodged Extinction" article HERE.
Which brings us sorta full circle, since the several chapters of Genesis after the Flood tell how the different races and ethnicities sprang from the sons of Noah.