Posted on 12/21/2002 3:54:34 AM PST by Pharmboy
Scientists studying the DNA of 52 human groups from around the world have concluded that people belong to five principal groups corresponding to the major geographical regions of the world: Africa, Europe, Asia, Melanesia and the Americas.
The study, based on scans of the whole human genome, is the most thorough to look for patterns corresponding to major geographical regions. These regions broadly correspond with popular notions of race, the researchers said in interviews.
The researchers did not analyze genes but rather short segments of DNA known as markers, similar to those used in DNA fingerprinting tests, that have no apparent function in the body.
"What this study says is that if you look at enough markers you can identify the geographic region a person comes from," said Dr. Kenneth Kidd of Yale University, an author of the report.
The issue of race and ethnicity has forced itself to biomedical researchers' attention because human populations have different patterns of disease, and advances in decoding DNA have made it possible to try and correlate disease with genetics.
The study, published today in Science, finds that "self-reported population ancestry likely provides a suitable proxy for genetic ancestry." In other words, someone saying he is of European ancestry will have genetic similarities to other Europeans.
Using self-reported ancestry "is less expensive and less intrusive" said Dr. Marcus Feldman of Stanford University, the senior author of the study. Rather than analyzing a person's DNA, a doctor could simply ask his race or continent of origin and gain useful information about their genetic make-up.
Several scientific journal editors have said references to race should be avoided. But a leading population geneticist, Dr. Neil Risch of Stanford University, argued recently that race was a valid area of medical research because it reflects the genetic differences that arose on each continent after the ancestral human population dispersed from its African homeland.
"Neil's article was theoretical and this is the data that backs up what he said," Dr. Feldman said.
The new result is based on blood samples gathered from around the world as part of the Human Genome Diversity Project, though on a much less ambitious scale than originally intended. Dr. Feldman and his colleagues analyzed the DNA of more than 1,000 people at some 400 markers. Because the sites have no particular function, they are free to change or mutate without harming the individual, and can become quite different over the generations.
The Science authors concluded that 95 percent of the genetic variations in the human genome is found in people all over the world, as might be expected for a small ancestral population that dispersed perhaps as recently as 50,000 years ago.
But as the first human populations started reproducing independently from one another, each started to develop its own pattern of genetic differences. The five major continental groups now differ to a small degree, the Science article says, as judged by the markers. The DNA in the genes is subject to different pressures, like those of natural selection.
Similar divisions of the world's population have been implied by earlier studies based on the Y chromosome, carried by males, and on mitochondrial DNA, bequeathed through the female line. But both elements constitute a tiny fraction of the human genome and it was not clear how well they might represent the behavior of the rest of the genome.
Despite the large shared pool of genetic variation, the small number of differences allows the separate genetic history of each major group to be traced. Even though this split broadly corresponds with popular notions of race, the authors of Science article avoid using the word, referring to the genetic patterning they have found with words like "population structure" and "self-reported population ancestry."
But Dr. Feldman said the finding essentially confirmed the popular conception of race. He said precautions should be taken to make sure the new data coming out of genetic studies were not abused.
"We need to get a team of ethicists and anthropologists and some physicians together to address what the consequences of the next phase of genetic analysis is going to be," he said.
Some diseases are much commoner among some ethnic groups than others. Sickle cell anemia is common among Africans, while hemochromatosis, an iron metabolism disorder, occurs in 7.5 percent of Swedes. It can therefore be useful for a doctor to consider a patient's race in diagnosing disease. Researchers seeking the genetic variants that cause such diseases must take race into account because a mixed population may confound their studies.
The new medical interest in race and genetics has left many sociologists and anthropologists beating a different drum in their assertions that race is a cultural idea, not a biological one. The American Sociological Association, for instance, said in a recent statement that "race is a social construct" and warned of the "danger of contributing to the popular conception of race as biological."
Dr. Alan Goodman, a physical anthropologist at Hampshire College and an adviser to the association, said, "there is no biological basis for race." The clusters shown in the Science article were driven by geography, not race, he said.
But Dr. Troy Duster, a sociologist at New York University and chairman of the committee that wrote the sociologists' statement on race, said it was meant to talk about the sociological implications of classifying people by race and was not intended to discuss the genetics.
"Sociologists don't have the competence to go there," he said.
That was Toba in Sumatra. I've seen estimates that only 5,000 people worldwide survived this incident.
Does Race Exist? A proponent's perspective by George W. Gill. (he says "yes")
Does Race Exist? An antagonist's perspective by C. Loring Brace. (he says "no")
RACE DOESN’T EXIST . (this discusses both views)
The Family Bush
 The branch lengths illustrate the number of genetic differences, not only between species, but among species as well. The pruned bush for humans shows how little genetic diversity exists. (Marco Doelling/ABCNEWS.com) |
I think it's the ability to make tools that has reduced human genetic diversity. It has also reduced the need for genetic diversity.
Rather than waiting for time and evolution to kill off one genetic population and enhance another, humans make tools for themselves that work much faster. Before evolution can kick in, humans have already fixed the situation.
That means that a person's genetic makeup is less important than his ability to use his brain. "Genetically inferior" people can make contributions that overpower the evolutionary threat. Someone once said that if we outlawed eyeglasses, the gene for near-sightedness would disappear, along with the people that carried it. But the simple "tool" of eyeglasses lets these "inferior" people thrive and survive, and contribute more to society than what the glasses cost.
"Brain" short-circuits evolution because it works faster than evolution. Genetic differences become small and meaningless because everybody has the tools needed to survive, regardless of the genes one was born with. If the earth was hit by a killer asteroid, humans would get busy with making new tools, while the other creatures could only "ride it out", and hope that their genes are good enough to get some of them through.
But an Italian and a North African aren't very different. And the North African isn't very different from an Ethiopian, and they're black. It's not the case that's you're simply in one category or another.
The idea of simple categories comes from the historical accident that early America was settled by immigrants from northern Europe and slaves from equitorial Africa.
I bet if they'd look specifically at North Africans, they'd have both European and African markers.
No they wouldn't.
Yup. Last time, it left six feet of ash in Nebraska.
The idea of simple categories comes from the historical accident that early America was settled by immigrants from northern Europe and slaves from equitorial Africa.
The existence of ovals does not mean that that there are no such things as circles or squares.
Given that circles and squares exist, we can take square-ish ovals and place them in the category of square-like objects and we can take round-ish ovals and place them in the category of circle-like objects. Questions of race can be handled similarly.
If Finns and Chippewa get along because they have linguistic and cultural similarities, then you need to take that fact and tell it to the Serbs, Croatians, and Bosnians. After that you can go to Rwanda and talk to the Hutu and Tutsi tribesmen.
The fact that all dogs are descended from wolves does not mean that we can't categorize certain dogs as having features that match a pre-defined description of Basset Hounds or Poodles. The fact that some dogs look like a kind of a mix between a Basset Hound and a Poodle does not mean that we cannot define the difference.
That the difference between humans should be immaterial to the way a government treats someone, or the rights they are entitled to, or to their status in life should not negate an objective look at their differences. Why someone would want to persue such a scientific path is a different matter. The Nazis wanted to prove that Germans were superior. Most grants are given now in an effort to prove there are no differences when such differences clearly exist. Both are persuing a political end not a scientific one.
In the end we are all humans, with dreams, aspirations, and emotions. We all want the best for our children. We all want a government that treats us with equal opportunity yet preserves our ability to seize that opportunity to rise above the mean based on our own knowledge, skills, and abilities even if that equality of opportunity puts some individuals behind other individuals (regardless of race) in outcome.
Freedom. Free to succeed, free to fail.
Security. Safe from failure, safe from success.
Dog breeds are a little different though because whoever decides what the dog is supposed to look like can decide what differences belong and which don't. If I decided to make a breed of red-headed humans, I could say certain hair tones or skin tones didn't fit and throw them out but who gets to say who belongs to one race or another? At what time does one race break off another race? I'm not saying we can or cannot define races but it seems pretty arbitrary and up to the definer and humans aren't quite like dogs because we don't have the same kind of breeding programs. Sort of like Indian tribes now ---who gets to say who is still an Indian ---some of those casino owners don't exactly look that much Indian.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.