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Biological differences among races do not exist, WU research shows

Biological differences among races do not exist, WU research shows

By Tony Fitzpatrick

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.

Alan R. Templeton, Ph.D., professor of biology in Arts and Sciences, 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 type of qualitative 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, there is no such thing as race.

"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," Templeton said. "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 cautioned. "There are differences, but they don't define historical lineages that have persisted for a long time."

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

"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," said 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," Sussman continued, "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 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 said. "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 said. "Rather, all of humanity is a single long-term evolutionary lineage."

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