Thanks for your answer.

As we know except for the skin colour, the races share other common physical characteristics, too. Like for example, the upper leg bone (femur) of Africans is straight while that of Europeans for example is curved.

And I am sure you are familiar with the Galapagos finches who consist of 14 species but have one ancestor species. They came into existence through a geographical separation on many islands and today, those species cannot cross-breed and produce fertile progeny.

You do not think that the species homo sapiens sapiens could have undergone the same changes if the races would been separated locally for longer times?