[Paleopsych] Scientists Reveal Map of Human Genetic Variation and Warn That It Does Not Reflect Racial Differences

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Scientists Reveal Map of Human Genetic Variation and Warn That It Does Not
Reflect Racial Differences
News bulletin from the Chronicle of Higher Education, 5.2.18
http://chronicle.com/prm/daily/2005/02/2005021805n.htm

[We should watch for cutbacks in these warnings.]

    [45]By LILA GUTERMAN

    Washington

    Scientists from a company in California revealed on Thursday a map of
    genetic variation across populations. Hailed as possibly a significant
    step toward an era of personalized medicine, the map also raised
    concerns that it would be publicly misunderstood as proving a genetic
    basis for race.

    The scientists, from the genetics company Perlegen Sciences, announced
    their findings at the annual meeting here of the American Association
    for the Advancement of Science. Their results will also be published
    in today's issue of the journal Science.

    The map's importance derives from the fact that many diseases and
    medicines affect people differently, at least in part because of
    variation in genes. But single genetic differences often do not
    explain the differences in responses to diseases or drugs.

    David R. Cox, Perlegen's chief scientific officer, said on Thursday
    that looking simultaneously at multiple genetic differences among
    people could produce a sort of "bar code" to predict the
    susceptibility of a given person to cancer, for instance, or whether a
    drug would lower an individual's blood pressure.

    He and his colleagues looked at 1.6 million sites in the human genome
    where differences in DNA are common among people. At those sites,
    people have one of two chemical letters. The scientists analyzed which
    letter occurred at each of the 1.6 million sites in the DNA of 71
    Americans -- 23 of African ancestry, 24 of Asian ancestry, and 24 of
    European ancestry. They found that, for most of the sites, all three
    groups bore both chemical spellings, but often in differing
    frequencies.

    The scientists plan to use their results to look for different genetic
    spellings associated with susceptibility to various diseases or
    responses to drugs. Scientists would do that by checking for
    differences between smokers with cancer and those without, for
    instance, or between people whose blood pressure goes down after
    taking a drug and those whose blood pressure stays the same. The
    company has made its data publicly available on its [62]Web site. The
    data are also available on the California Institute for
    Telecommunications and Information Technology's [63]Web site.

    In an essay that will be published with the Perlegen paper, two
    scholars -- David Altshuler, of the Broad Institute of Harvard
    University and Massachusetts Institute of Technology, and Andrew G.
    Clark, of Cornell University -- write that the company's data are "of
    exceptionally high accuracy."

    For about 18 percent of the sites, however, only one of the ethnic
    groups bore two spellings; the other groups had only one spelling. But
    Dr. Cox emphasized that such a pattern does not mean the genetic
    variations underlie race.

    "Trying to use DNA to define race is like putting a square peg in a
    round hole," he said.

    In an interview, Troy Duster, a professor of sociology at New York
    University, agreed. He said he was concerned that studies like
    Perlegen's could "give a kind of imprimatur of scientific authority"
    to the notion that race is biologically determined.

    He pointed out that the 71 individuals do not represent all of the
    genetic diversity of their races, and that genetic differences would
    exist between any two small groups of people.

    "If you took a group of people from the East Coast and the West Coast
    ... you'd find differences," he told The Chronicle. "You wouldn't
    conclude there were genetic differences between the two coasts. But
    with race or ethnicity, people are preprogrammed at a cognitive level
    to think in terms of these genetic categories."

    Mr. Duster writes, in another essay in Science, that studies like
    Perlegen's "should always attach a caveat or warning label like this:
    '[Genetic] frequencies vary between any selected human groups -- to
    assume that those variations reflect 'racial categories' is
    unwarranted.'"

    More studies are sure to appear shortly. An international group of
    government-backed scientists is working on a similar project, called
    the International Haplotype Map Project ([64]The Chronicle, October
    30, 2002), and in recent months, the Perlegen scientists have joined
    forces with them.
      _________________________________________________________________

    Background article from The Chronicle:
      * [65]International Team Begins New Map of Human Genome, Seeking
        Variations Within Large Blocks of DNA (10/30/2002)

References

   45. mailto:lila.guterman at chronicle.com
   62. http://genome.perlegen.com/
   63. http://research.calit2.net/hap/wgha/
   64. http://chronicle.com/daily/2002/10/2002103001n.htm
   65. http://chronicle.com/daily/2002/10/2002103001n.htm

E-mail me if you have problems getting the referenced articles.