Feature

Skin colour and race

Lynne Smit

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.

Until recently, few scientists had tried to measure skin pigmentation, shrouded as it is in a veil of political and emotional complexity. “Only a few groups have been courageous or stupid enough to care about measuring skin-colour,” Shriver told delegates wryly.

But the results and findings of such work would undoubtedly help to demystify race, he said.

“If we know more about (skin pigmentation), tell the story of how it happened, it has the potential to remove (race) as a big issue about how populations are different from each other.”

Race, Shriver said, was composed of three elements: ethnic heritage (the social aspect), biogeographical ancestry (the biological component) and the interaction of the two.

But race is complex, and the mixing of cultural and biological aspects of population differences means you can’t talk about one without talking about the other, he said. “Race is a mixed variable and requires deconvolution and deconstruction”.

Responding to Shriver’s address, Irvine chair and Curator of Anthropology at the California Academy of Sciences Nina Jablonski pointed out that racial categories were invented in the past, have been reinvented in the present and are largely worthless, pejorative and harmful.

“What we really need to consider … is humans as individuals. We need ultimately to understand the diversity of humans on earth and not try to cluster them in terms of erroneous and misleading categories that are easy, convenient, occasionally useful with social or medical results, but which are generally of extremely limited utility,” said Jablonski.

“What (Shriver’s) and other research is showing us, is that skin pigmentation as a primary feature of racial classification, is extremely complex and cannot be treated as a single entity”.

Shriver added in his paper that advances in understanding human pigmentation would soon lead to methodological and conceptual breakthroughs about how evolution happened. Scientists were already convinced that there was no such thing as “pure human stock”, that no population was more highly evolved than any other and that population differences have generally been misunderstood and misused.

“We don’t believe in typological race,” he said. Most racial categories used over the last 200 years did not have any benefit of genetic information, added Jablonski. “By continuing to use simple racial classifications based on visual impressions, we are confounding a range of complex biological phenomena”.

More information:

The Beyond Race Conference was organised by the Africa Genome Education Institute - www.africagenome.co.za

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