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.
No they wouldn't.
Why not? Here is a page describing the various subspecies of tigers. They differ by color, size, and coat. Here is a page describing the subspecies of Jardines. They differ primarily in coloration. Why could you not describe a small Bushman of Southern Africa, with dark skin and curly hair as different in subspecies from that of a tall North America Lakota Sioux with much lighter skin and straight hair? Is it because it is the "third rail" of anthropology? Is it too political? How are the differences that create subspecies defined? Are humans the only mammals without defined subspecies?
If, on the other hand, racial differences do exist, some differences would be good for society and some differences would be bad for society. Some races would be taller. Some races would be more artistic. Some races would be more intellegent. Some races would be more civilized.
Defining differences in race, even on a DNA scale, can only get a person in big trouble with the PC crowd.
By the way I believe we are all one race, created in the image of God. Please don't ask me what God looks like. I don't know.
Chimps make crude tools, too. They just don't use them as a major survival device.
There must have been a time when man started to depend on tools to stay alive, rather than just something to snag the hard-to-reach fruit off the tree. "Tools" include weapons, and farming implements. Man could then explore other climates and regions, and become a hunter, rather than just lunch.
I once read an article (that I can no longer recollect) that theorized that humanity's final burst of evolutionary change was in changing from another Great Ape into a toolmaker. Full-color stereoscopic vision, optimized for up-close work, is great for a toolmaker. Tools and hands shaped each other, which is why our hands and feet are so different from that of other apes. In fact, the need to carry and use tools put humans on their two feet, and gave them a taller vantage point to scan the rest of the world.
If you want to. But circle-like and circle aren't the same thing. Circle-like is a mental category to make things easier, which is say a construct. That it's based on an underlying reality doesn't make it less of a construct.
Questions of race can be handled similarly.
What questions of race do you have in mind?
Which is to say.
So you're saying that you could easily mistake some children from a Scandinavian family for some children from a Ghanan family?
No, of course you're not. Race is a perfectly obvious phenomenon; it's no more a social construct than gravity is. Scientists who try to obfuscate what is everyday common sense are merely bringing science into disrepute.
The scientific field is called "Taxonomy." There are people who devote their lives to placing things into categories. The oft-raised question is: can humans be categorized by what are commonly called "racial characteristics"? I'm not a taxonomist, it doesn't really matter to me. It apparently does matter to a lot of people. The government is constantly asking me "which race" I belong to. I on the other hand, do care when people want to deny that there are differences between things such as circles and squares. That kind of ignoring the obvious can lead to pseudoscience.
In other news, scientists figure out that there were originally five different sets of marshmellows in Lucky Charms.
I never said there can't be races basic geometric forms but what they are is up to whoever is defining them. Your example is obvious ---but what about not so pale Europeans ovals? Are Greeks and Italians pentagons and hexagons a different race geometric form from Scandinavians circles? Or from Persians and Arabs rhombuses and parallelograms? Or are Persians parallelograms an Asian race actually triangles? I've read people from India hexagons are considered Caucasians ovals which makes sense I guess but racially geometrically they seem different than your Scandinavians circles.
Brilliant! Why didn't I think of that? (Don't answer that...)
Races are a temporary evolutionary phenomenon based upon pre-historic geographical isolation. Now that geographical isolation has been eliminated, the trend will be back to a single more homogeneous race. Ten thousand years from now there will be no distinctive races.
This assumes that there will be constant intermarriage, or at least inter-group breeding, among all presently-existing races. Will this be true for the pygmis, for example? Maybe not. There could be groups that may continue to be genetically isolated. We don't really know.
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