Should we accept that Africa is the birthplace of the human race ( many do not ) and that some people left the continent and populated most habitable areas all over the world, why are there then so many races ? Races that differ in appearances, culture, the languages they speak, their levels of development, their economic activities etc. Even the African racial groups differ in many ways.
Accepting that all races possess the same genes, what then is responsible for the obvious differences? The geneticists' explanation is that races possess the same genes but in different proportions. If that is the case then how did the proportions change since homo sapiens made its first appearance?
Some believe that Darwin's theory of "Evolution" explains the changes, but there are also other highly plausible explanations. Genetic mutation is one. An example of mutation is a recent case where an orange farmer near Citrusdal in the Western Cape noticed that baboons were targeting one tree in his orchard weeks before harvest time. A genetic mutation had changed that tree so that its fruit could be harvested sooner. A mutation causes dramatic change much faster than evolution.
There are however also two othet forces, much like evolution that might effect differences. They are "genetic drift" and the "founder effect". Genetic drift refers to random changes in genetic frequencies that can occur over time especially in small populations. In a small population such a change can become permanent.
The "founder effect" is a more severe form of "genetic drift" If for instance a person in an isolated group possesses a rare gene , that gene may become more common in a small group than it would have become in a large population. The great Kenyan middle distance runners who are concentrated in a small area, might be good example. One of the small number of Dutch Settlers who arrived at the Cape in 1652 had Huntington's disease. Today it is much more common in South Africa than in Holland.
That the population groups (races) are different and that they change with time are facts and it will be to our advantage if we accept our differences and live together like civilized beings we claim to be. Races have different cultures but there are moral rules or principles that are accepted almost everywhere. If everybody abides by these rules there will be little friction in society.