[Paleopsych] ABC: Ancient DNA may be misleading scientists

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News in Science - Ancient DNA may be misleading scientists - 18/02/2003
    Tuesday, 18 February 2003

    Ancient DNA in skeletons has a tendency to show damage in a particular
    region, resulting in misleading genetic data and mistaken conclusions
    about the origin of the skeleton, British scientists said.
    A group of researchers at the [4]Henry Wellcome Ancient Biomolecules
    Centre of the University of Oxford, in Britain, made the finding while
    studying Viking specimens. They found that about half of the specimens
    had DNA that suggested they were of Middle Eastern origin.
    But more detailed analysis revealed that many of the genetic sequences
    in the double helix molecule, which carries the genetic information of
    every individual, were damaged at a key base that separates European
    sequences from Middle Eastern genetic types - damage which made the
    skeletons appear to have originated in the Levant.
    The results are published in the February 2003 issue of the
    [5]American Journal of Human Genetics.
    Damage events appear to be concentrated in specific 'hotspots',
    indicating that a high proportion of DNA molecules can be modified at
    the same point. These hotspots appear to be in positions that also
    differ between different human groups. In other words, the DNA damage
    discovered affects the same genetic positions as evolutionary change.
    "Now that this phenomenon has been recognised, it is possible to
    survey the ancient sequences for damage more accurately, and determine
    the correct original genetic type - open the way for more reliable
    future studies," said Professor Alan Cooper, director of the centre.
    Cooper has hopes the finding may have implications for future
    research. "It also appears that we can use damage cause after death to
    examine how DNA damage occurs during life - a completely
    unanticipated, and somewhat ironic result," he said. "Potentially this
    allows us to get uniquely separate views of the two major evolutionary
    processes, mutation and selection."

                                       Danny Kingsley - ABC Science Online


    4. http://abc.zoo.ox.ac.uk/
    5. http://www.journals.uchicago.edu/AJHG/home.html

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