According to our current understanding of the DNA evidence, somewhere around 50,000 to 75,000 years ago, about 600 people, out of the total human population of about 1,500 people, left Africa. The ancestors of those 600 people populated the rest of the earth. The thinking – which is being refined on an almost daily basis as we learn more from massive DNA sampling, among other things – is that they crossed the water somewhere around where the Red Sea changes into the Gulf of Aden and then slowly worked their way along the coast, to south-eastern Europe and India. From India, some humans migrated deeper into Asia. Some of those humans migrated to what we now call China and eventually, even to the Americas while others doubled back to northern Europe.

Just as the migration out of Africa involved a sub-set of the entire human population, each additional migration was a sub-set of the original migration. As a result, there is more human genetic diversity in Africa than the rest of the world put together and way more than, say, in Europe. Because of this, the chances are good that the shortest Olympian would be of African heritage just like the chances are good that the tallest Olympian, DeAndre Jordan, would be of African heritage. Interestingly enough, the chances are that the smartest Olympian is also of African heritage.