[Paleopsych] Racial groupings match genetic profiles, Stanford study finds

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Racial groupings match genetic profiles, Stanford study finds

[Thanks to Ted for finding this article.]

    Contact: Amy Adams
    [3]amyadams at stanford.edu
    [4]Stanford University Medical Center

          Racial groupings match genetic profiles, Stanford study finds

    STANFORD, Calif. - Checking a box next to a racial/ethnic category
    gives several pieces of information about people - the continent where
    their ancestors were born, the possible color of their skin and
    perhaps something about their risk of different diseases. But a new
    study by researchers at the Stanford University School of Medicine
    finds that the checked box also says something about a person's
    genetic background.

    This work comes on the heels of several contradictory studies about
    the genetic basis of race. Some found that race is a social construct
    with no genetic basis while others suggested that clear genetic
    differences exist between people of different races.

    What makes the current study, published in the February issue of the
    American Journal of Human Genetics, more conclusive is its size. The
    study is by far the largest, consisting of 3,636 people who all
    identified themselves as either white, African-American, East Asian or
    Hispanic. Of these, only five individuals had DNA that matched an
    ethnic group different than the box they checked at the beginning of
    the study. That's an error rate of 0.14 percent.

    According to Neil Risch, PhD, a UCSF professor who led the study while
    he was professor of genetics at Stanford, the findings are
    particularly surprising given that people in both African-American and
    Hispanic ethnic groups often have a mixed background. "We might expect
    these individuals to cross several different genetic clusters," Risch
    said. This is especially true for Hispanics who are often a mix of
    Native American, white and African-American ancestry. But that's not
    what the study found. Instead, each self-identified racial/ethnic
    group clumped into the same genetic cluster.

    The people in this research were all part of a study on the genetics
    of hypertension, recruited at 15 locations within the United States
    and in Taiwan. This broad distribution is important because it means
    that the results are representative of racial/ethnic groups throughout
    the United States rather than a small region that might not reflect
    the population nationwide.

    For each person in the study, the researchers examined 326 DNA regions
    that tend to vary between people. These regions are not necessarily
    within genes, but are simply genetic signposts on chromosomes that
    come in a variety of different forms at the same location.

    Without knowing how the participants had identified themselves, Risch
    and his team ran the results through a computer program that grouped
    individuals according to patterns of the 326 signposts. This analysis
    could have resulted in any number of different clusters, but only four
    clear groups turned up. And in each case the individuals within those
    clusters all fell within the same self-identified racial group.

    "This shows that people's self-identified race/ethnicity is a nearly
    perfect indicator of their genetic background," Risch said.

    When the team further analyzed each of the four clusters, they found
    two distinct sub-groups within the East Asian genetic cluster. These
    two groups correlated with people who identified themselves as Chinese
    and Japanese. None of the other genetic groups could be broken down
    into smaller sub-sections. This suggests that there isn't enough
    genetic difference to distinguish between people who have ancestry
    from northern Europe versus southern Europe, for example. Risch
    admitted that few people in this study were of recent mixed ancestry,
    who might not fall into such neat genetic categories.

    This work could influence how medical research is carried out. Often
    researchers ask study participants to identify their race and
    ethnicity at the beginning of a clinical trial. The researchers can
    then follow people of different racial/ethnic groups to see which
    group is more likely to get a particular disease or respond well to a
    new treatment. This information can help future doctors know which
    patients may need additional disease screening or should receive one
    treatment over another.

    But recently some researchers have moved to examining genetic
    differences between participants rather than relying on race and
    ethnicity. Their reasoning is that genetic differences may be a more
    precise tool for tracking groups of patients. Risch points out that
    this genetic analysis is costly. If people fall into the same groups
    using self-identified race as using genetics, then that could bring
    down the expanding cost of medical research.


    Other Stanford researchers who participated in this work include Hua
    Tang, a graduate student now at the Fred Hutchinson Cancer Research
    Center, and Tom Quertermous, MD, the William G. Irwin Professor in
    Cardiovascular Medicine.

    Stanford University Medical Center integrates research, medical
    education and patient care at its three institutions - Stanford
    University School of Medicine, Stanford Hospital & Clinics and Lucile
    Packard Children's Hospital at Stanford. For more information, please
    visit the Web site of the medical center's Office of Communication &
    Public Affairs at [5]http://mednews.stanford.edu.

    PRINT MEDIA CONTACT: Amy Adams at (650) 723-3900
    ([6]amyadams at stanford.edu)
    BROADCAST MEDIA CONTACT: M.A. Malone at (650) 723-6912
    ([7]mamalone at stanford.edu)


    3. mailto:amyadams at stanford.edu
    4. http://med-www.stanford.edu/MedCenter/MedSchool/
    5. http://mednews.stanford.edu/
    6. mailto:amyadams at stanford.edu
    7. mailto:mamalone at stanford.edu
    8. http://www.eurekalert.org/pubnews.php
    9. http://www.eurekalert.org/emailrelease.php?file=sumc-rgm012705.php

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