In My Opinion

Letter to the Editor of DISCOVER:


    I was so dubious of Feldman's conclusions about human origins (page 56, right column, #7) that I looked up the research on which it was based, and it seems he is telling us what he thinks we ought to believe, rather than what the data really implies.
He says:
   "Humans are all so closely related that our entire population shows less genetic diversity than that of a small group of chimpanzees. It's almost as though we all came from the same town ... and perhaps we did."...but, for the truth click here [the comment] is based on a study by Marcus Feldman, a population geneticist at Stanford University;  Noah Rosenberg, a computational biologist at the University of Southern California in Los Angeles;  and Lev Zhivotovsky, a geneticist at the Russian Academy of Sciences, Moscow. They examined short, repetitive fragments of DNA called microsatellites, markers found in every person.  'We used 377 markers that are generally located in non-coding regions of the genome, ones that are likely to be neutral, where there is no natural selection involved,' says Rosenberg.  The beauty of microsatellites is that they mutate frequently, at a steady pace, enabling scientists to infer ... when human populations first diverged from each other. Studying those mutations in 1,056 individuals clustered in 52 populations groups around the world ..."

    Feldman, and his research associates, are mentioned in a paper by David Rotman, called "Genes, Medicine, and the New Race Debate" from Technology Review; Jun2003, Vol. 106, issue 5, pg. 41. The abstract mentions the "danger of looking for genetic variations among racial groups."
    The danger of these genetic discoveries! If the data really indicated that 'we are all the same' and 'we are all Africans', (as the media science-writers confidently assure us) would these researchers think that is 'dangerous'? You know better; but we don't have to infer their views: they tell us, in that paper, what they fear and why. First, they tell us that the HapMap "will make it possible to spell out in great detail the genetic differences between people from different parts of the world". [Those differences that Feldman claims hardly exist!] So, "Sociologists, bioethicists, and anthropologists worry that the genetic data could be manipulated to give an air of biological credence to ethnic stereotypes, to revive discredited racial classifications, & even to fuel bogus claims of fundamental genetic differences between groups." [my emphasis] 
    "Here's the rub", says Troy Duster, a sociologist, "...The danger" [there it is again, that danger] is that people will associate those differences with racial groups, and Jonathan Kahn, bioethicist, suggests that, "it is all too easy for biological and genetic categories to become conflated with racial ones." No doubt they will, because that is exactly what the data implies: Feldman's own researchers reported " ... detailed data on gene samples from individuals from 52 populations..." and, bottom line: "how people categorized themselves - whether they called themselves black or white or asian - correlated closely with the genetic categories."
    Duster thinks that ordinary folk are not to be trusted with this "dangerous" genetic knowledge: he says that " map differences between various populations while avoiding the dangers of racial stereotypes is a conundrum without an answer." He doesn't quite say the truth should be withheld from us vulgar rabble, but it is clearly implied that genetic researchers had better come to the right conclusions when reporting research.  Feldman's DISCOVER comments seem to be an example of concealing that "dangerous" truth!
    Feldman claims those 377 microsatellites show so little diversity we could all be from one village, but this is the same data-set, that is discussed in Does Race Exist, Sci. Am., Dec 2003. That article grudgingly admitted the race-genetic correlation. "...we needed  60 polymorphisms to assign individuals to their continent of origin with 90% accuracy. To achieve nearly 100% accuracy, however, we needed to use about 100...". This article reveals that Noah Rosenberg and Jonathan Pritchard, formerly of Feldman's laboratory used 375 of those sets of polymorphisms from 1000 people of 52 ethnic groups to find that, " looking at varying frequencies of these polymorphisms they were able to distinguish five different groups of people whose ancestors were typically isolated by oceans, deserts, or mountains: sub-Saharan Africans; Europeans and Asians west of the Himalayas; east Asians; ... Melanesia; and Native Americans." They were also able to identify subgroups within each region that usually corresponded with each member's self-reported ethnicity". [What a village!] That information is all extracted from the variation among those microsatellites that Feldman characterizes as having "less diversity than a chimpanzee troop". While perhaps technically true, the impression imparted is deceptive.
     Feldman asserts that we "are all so closely related" because there is 'so little diversity' among those carefully chosen microsatellites. Here's a quote from the abstract of, Human Genetic Diversity: Lewontin's Fallacy, A.W.Edwards, Bioessays Aug 2003; Vol. 25: (8) 798-801
that gives perspective on Feldman's conclusions. "In popular articles that play down the genetical differences among human populations, it is often stated that about 85% of the total genetic variation is due to individual differences within populations and only 15% to differences between populations or ethnic groups. ...this argument ignores the fact that most of the information that distinguishes populations is hidden in the correlation structure of the data and not simply in the variation of the individual factors." In other words, this is a deceitful argument, and those who make it know that.

     Even the NY Times, that bastion of PC, is beginning to admit the truth about Lewontin’s error, albeit only in an OP-editorial. On March 14, 2005, ARMAND MARIE LEROI wrote specifically about Lewontin, in the aptly titled, A Family Tree in Every Gene:

“The [Lewontin’s] error is easily illustrated. If one were asked to judge the ancestry of 100 New Yorkers, one could look at the color of their skin. That would do much to single out the Europeans, but little to distinguish the Senegalese from the Solomon Islanders. The same is true for any other feature of our bodies. The shapes of our eyes, noses and skulls; the color of our eyes and our hair; the heaviness, height and hairiness of our bodies are all, individually, poor guides to ancestry. But this is not true when the features are taken together. Certain skin colors tend to go with certain kinds of eyes, noses, skulls and bodies. When we glance at a stranger's face we use those associations to infer what continent, or even what country, he or his ancestors came from - and we usually get it right. To put it more abstractly, human physical variation is correlated; and correlations contain information.

Genetic variants that aren't written on our faces, but that can be detected only in the genome, show similar correlations. It is these correlations that Dr. Lewontin seems to have ignored. In essence, he looked at one gene at a time and failed to see races. But if many - a few hundred - variable genes are considered simultaneously, then it is very easy to do so. Indeed, a 2002 study by scientists at the University of Southern California and Stanford showed that if a sample of people from around the world are sorted by computer into five groups on the basis of genetic similarity, the groups that emerge are native to Europe, East Asia, Africa, America and Australasia - more or less the major races of traditional anthropology.”

Read the second question and answer How genetically diverse are humans? especially the paragraph starting with Obviously, humans are not at the low end of the genetic diversity spectrum, particularly in relation to other mammals., found in this site


More on this subject at: The Genetic Reality of Race

                     [In My Opinion Printer Friendly]