9 October 1998

Genetically Speaking, Race Doesn't Exist In Humans

Race doesn't matter. In fact, it doesn't even exist in humans. While that may sound like the idealistic decree of a minister or rabbi, it's actually the conclusion of an evolutionary and population biologist at Washington University in St. Louis.

Alan R. Templeton, Ph.D., professor of biology in Arts and Sciences at Washington University, has analyzed DNA from global human populations that reveal the patterns of human evolution over the past one million years. He shows that while there is plenty of genetic variation in humans, most of the variation is individual variation. While between-population variation exists, it is either too small, which is a quantitative variation, or it is not the right qualitative type of variation -- it does not mark historical sublineages of humanity.

Using the latest molecular biology techniques, Templeton has analyzed millions of genetic sequences found in three distinct types of human DNA and concludes that, in the scientific sense, the world is colorblind. That is, it should be.

"Race is a real cultural, political and economic concept in society, but it is not a biological concept, and that unfortunately is what many people wrongfully consider to be the essence of race in humans -- genetic differences," says Templeton. "Evolutionary history is the key to understanding race, and new molecular biology techniques offer so much on recent evolutionary history. I wanted to bring some objectivity to the topic. This very objective analysis shows the outcome is not even a close call: There's nothing even like a really distinct subdivision of humanity."

Templeton used the same strategy to try to identify race in human populations that evolutionary and population biologists use for non-human species, from salamanders to chimpanzees. He treated human populations as if they were non-human populations.

"I'm not saying these results don't recognize genetic differences among human populations," he cautions. "There are differences, but they don't define historical lineages that have persisted for a long time. The point is, for race to have any scientific validity and integrity it has to have generality beyond any one species. If it doesn't, the concept is meaningless."

Templeton's paper, "Human Races: A Genetic and Evolutionary Perspective," is published in the fall 1998 issue of American Anthropologist, an issue almost exclusively devoted to race. The new editor-in-chief of American Anthropologist is Robert W. Sussman, Ph.D., professor of anthropology in Arts and Sciences at Washington University in St. Louis.

Sussman and his guest editor for this issue, Faye Harrison, Ph.D., professor of anthropology at the University of South Carolina, have enlisted the talents and expertise of anthropologists across the discipline's four subdivisions -- biological, socio-cultural, linguistics and archeological anthropology -- plus Templeton and literary essayist Gerald L. Early, Ph.D., Merle Kling Professor of Modern Letters in Arts and Sciences at Washington University in St. Louis, to provide a renewed perspective on race, a topic that historically is linked closely to anthropology.

"The folk concept of race in America is so ingrained as being biologically based and scientific that it is difficult to make people see otherwise," says Sussman, a biological anthropologist. "We live on the one-drop racial division -- if you have one drop of black or Native American blood, you are considered black or Native American, but that doesn't cover one's physical characteristics. Templeton's paper shows that if we were forced to divide people into groups using biological traits, we'd be in real trouble. Simple divisions are next to impossible to make scientifically, yet we have developed simplistic ways of dividing people socially." Single Evolutionary Lineage

Templeton analyzed genetic data from mitochondrial DNA, a form inherited only from the maternal side; Y chromosome DNA, paternally inherited DNA; and nuclear DNA, inherited from both sexes. His results showed that 85 percent of genetic variation in the human DNA was due to individual variation. A mere 15 percent could be traced to what could be interpreted as "racial" differences.

"The 15 percent is well below the threshold that is used to recognize race in other species," Templeton says. "In many other large mammalian species, we see rates of differentiation two or three times that of humans before the lineages are even recognized as races. Humans are one of the most genetically homogenous species we know of. There's lots of genetic variation in humanity, but it's basically at the individual level. The between-population variation is very, very minor."

Among Templeton's conclusions: there is more genetic similarity between Europeans and sub-Saharan Africans and between Europeans and Melanesians, inhabitants of islands northeast of Australia, than there is between Africans and Melanesians. Yet, sub-Saharan Africans and Melanesians share dark skin, hair texture and cranial-facial features, traits commonly used to classify people into races. According to Templeton, this example shows that "racial traits" are grossly incompatible with overall genetic differences between human populations.

"The pattern of overall genetic differences instead tells us that genetic lineages rapidly spread out to all of humanity, indicating that human populations have always had a degree of genetic contact with one another, and thus historically don't show any distinct evolutionary lineages within humanity," Templeton says. "Rather, all of humanity is a single long-term evolutionary lineage."

Templeton's analysis gives impetus to the trellis model of evolutionary lineages, as opposed to the candelabra model, still popular among many anthropologists. The candelabra model generally holds that humanity first evolved in Africa and then spread out of Africa into different populations in Europe and Asia. Picture a candelabra, then imagine three distinct populations emerging from a single stem, each of them separate genetic entities that have not mixed genes, and thus are distinct, biological races.

The trellis model pictures humanity as a latticework, each part having a connection with all other parts. It recognizes that modern humans started in Africa about 100 million years ago, but as humans spread, they also could, and did, come back into Africa, and genes were interchanged globally, not so much by individual Don Juans as through interchanges by adjacent populations.

"If you look down at any one part of a trellis, you see that all parts are interconnected," Templeton explains. "Similarly, with modern molecular evolutionary techniques, we can find over time genes in any one local area of humanity that are shared by all of humanity throughout time. There are no distinct branches, no distinct lineages. By this modern definition for race, there are no races in humanity."

Out of Africa

The candelabra model often is used to justify the "out of Africa" replacement theory, whereby modern humans descended from a single African population, expanding out of Africa and replacing the less advanced Old World humans in Europe, Asia and Africa.

Templeton's analysis suggests a less hostile scenario. "Traits can spread out of Africa to all of humanity because all of humanity is genetically interconnected," he says. "Spreading traits doesn't require spreading out and killing off all the earlier people. They're spread by reproducing with people -- it's make love, not war."

Sussman says one of his motivations in devoting his first issue of American Anthropologist to race was to show the relevance of anthropology both in the academic world and in our everyday lives.

"Historically, race has been a key issue in anthropology," says Sussman. "Since about 1910, anthropologists have been fighting this lack of understanding of what people are really like, how people have migrated and mixed together.

Anthropologists such as Franz Boas, W.E.B. Dubois, Margaret Mead, Ruth Benedict and Ashley Montagu were in the forefront of warning people about the dangers of Nazism during the '30s and '40s, yet the anthropologists' profile on key issues in America has been so low recently that when President Clinton appointed a committee on race in 1997, there wasn't a single anthropologist on it.

"Anthropology, in some ways, has become too esoteric. One of my goals with the journal is to show what anthropologists are doing and how they relate to how we think and how we live."