Skin colour and race are all too often assumed to be the same thing, according to Pennsylvania State University’s Mark Shriver. Giving the keynote address at yesterday’s opening session of the “Beyond Race” conference in Somerset West, Shriver said that such an assumption was simplistic and stereotypical. Skin colour and race “are really not the same thing,” he told the 120 conference delegates who have gathered from more than a dozen countries around the world.
The conference, organized by the Africa Genome Education Institute, has been called to consider the genetics and social-ethical aspects of human variation in colour and disease. This includes the biology of pigmentation, along with other related topics. Shriver explained in his address that skin-colour varies across as well as within continents. There was an enormous amount of variation especially within Africa, he said. He compared the light skin-colour of the Khoisan, for instance, with the dark colour of the Senegalese. There are also dark-skinned people in India who have evolved dark skins independently from people with dark skins in Africa, he said. Likewise, north Europeans and east Asians are both light-skinned, for different evolutionary reasons.
The variation was a clear indication of how complex skin colour could be. “There are dark-skinned populations in most parts of the world and extensive variation in pigmentation in most regions”. However, by measuring skin-colour and looking at how it is affected by ultraviolet light, scientists have made some fascinating conclusions about how human beings have evolved, according to Shriver. “Skin colour and ultraviolent light intensity are correlated and this, with other features, makes us think that it has evolved as part of the process of natural selection”.
A high pigment content protects people from sunburn, some types of cancer, prevents the suppression of the immune system and protects folic acid from photolysis. A low pigment content allows for enhanced Vitamin D synthesis, the beneficial suppression of the immune system (necessary to prevent ailments such as multiple sclerosis and diabetes) and protection from cold damage. “Pigmentation is quite fascinating and a beautiful aspect of human biodiversity,” said Shriver. But much was imagined and it would be hard to “take the human out of the equation”. Skin-colour and appearance were politically-charged and were likely to remain so.
>> Lynne Smit <<