There are x8 Regions of the World
There are x8 Races of the World.
Each Region has and should have, a representation of each of the Races.
To use one race as an example: The Red Rangas
...in the northern hemisphere, they are smaller and mass produced. In the Southern hemisphere they are taller and more individual - just ask Blanka of South America!

There were x3 'Ancient' pre-Sapien races: One was in Europe (& Middle-East) - Neanderthal, One was in Asia - Denisovian, One was in Africa - unnamed. All three were exterminated and outbred by Homo-Sapiens.
Pure-breeding in Humanity is a genetic fragility.
It's the Mixed-Blood/Mongrels that are mentally and physically more adaptable and versatile.
...even now, new races are being born.