Did Noah and his boys or their wives carry the marked genes of Cain? Or, did the mark of Cain die with Cain? The post-Flood amalgamation that resulted in "certain races of men" is not the result of scientists uniting animal and human genes in a laboratory. Hopefully we can agree on this point. Therefore, we are left with two options (I'm sure somebody else can think of other options) - 1) "certain races of men" are a result of natural copulation, and 2) "certain races of men" are a result of genetic manipulation in laboratories.

The fact that people in Africa, as well as other southern climates have a history of predominantly living out in the open/nature, versus others who had to build climate shelters and thus naturally lived in them year round, among other factors, led to this skin adapting change over time, with not much reasons for a reversal either way after that in succeeding, much shorter, sheltered and comfortably living generations.

When we look around us today and see all of the different physical characteristics in people and relate this to Adam, who was the first man, we can see that in Adam the potential combination of genes was enormous. ...

Considering this fact, it is easier to understand how Adam produced all the different varieties we see in people today. Also very important is the evidence that after a number of generations, there appears to be strong evidence that certain genes become dominant and the variability of characteristics is limited.22 This does not mean that other genes are not present. However it does mean some genes, once they reach a point, become dominant and continue to be dominant in future generations. This only occurs with in breeding or selective breeding.

An example was my FDS (Field Dog Stud Book) registered Irish Setter "Bryan's Red Sun" (we just called him "Sam"). He was the product of selected breeding over many generations. As a dog breeder, one basic rule I quickly learned was that to produce an Irish Setter, I had to breed a male and female Irish Setter. This is where the term "pure breed" comes from. In other words, in Sam's historical blood line for several hundred years only dogs of the same family were bred together. No other breed of dog was allowed to "cross breed" into his blood line. The key to producing a particular breed is in isolation from other breeds. The genes which produced the red-colored hair and general physical appearance of the Irish Setter have become dominate by selective breeding, and consistently produce the same characteristics over and over again in every generation.

Through the example of Sam, we see that isolation of a group of dogs from other groups of dogs produces what could be called "race." Note, however, that even within the "race" or "breed" called Irish Setter there is still much potential for variation.

... In this paper we have seen that the decedents of Noah's three sons were generally dispersed over all the earth. Also, the physical characteristics of any of his sons were not exclusive to his progeny. Each could and did produce different colored offspring.

The most important factor in reaching an explanation for the origin of race is the understanding that as the migration from the Middle East proceeded, contact with other groups became less frequent, and finally each group became isolated from all others, and the groups became smaller. Because of this isolation men and women married within their own group. Thus in breeding took place within an isolated group and between kin.

An example of how isolation caused particular characteristics in a group of people would be the American Indian. The American Indian originated from oriental peoples who came across the Bering Strait which connected eastern Asia and Alaska. As they migrated south and east, they became isolated from the peoples of Asia. American Indians are considered to be Mongoloid people, but differ from Asian Mongoloids of China and Japan. One must assume that genetics caused the American Indian to be somewhat different from other Mongoloids of Asia. By moving into North America they became isolated from other Asian peoples. Their group was at first small and they married among their kin from within his group. The dominant genes of the group surfaced within a few generations and began to produce the general characteristics which are common to the American Indian today.

Some groups moved further south into Mexico and South America, and they, too, became isolated. This isolation caused somewhat differing physical appearances in each group. Thor Heyerdahl, the anthropologist, studied the people of North America and the Pacific islands for years. He has shown that the Polynesian people came from North America and migrated (in boats) to the Pacific Islands. The isolation of these people produced the Polynesian peoples.

Without isolation it is unlikely that "race" would have ever occurred. It is a vital part of understanding how genetics caused the different physical characteristics of isolated groups of people which we call races.

http://www.bible-truth.org/race.htm

The idea that Canaan was named after his mother's ancestor, Cain, and, therefore, most probably shares his black skin color, seems too far fetched to consider seriously, wouldn't you say?