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Biotech Science

Stem Cells Change Man's DNA 171

Posted by Zonk
from the oh-man-science-is-weird dept.
An anonymous reader writes "After receiving umbilical cord stem cells to replace bone marrow as treatment for non-Hodgkin's lymphoma, Greg Graves temporarily had three different sets of DNA. Eventually, one of the two sets of cells transplanted into his bone marrow took root, leaving him different DNA in his blood from the rest of his body: 'If you were to do a DNA test of my blood and one from my skin, they'd be different,' Graves said. 'It's a pretty wild thing.'"
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Stem Cells Change Man's DNA

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  • by h890231398021 (948231) on Friday October 05, 2007 @05:23PM (#20873675)
    Perhaps this is the beginning of the end for the use of DNA as "incontrovertable" evidence in criminal cases?
  • by pohl (872) on Friday October 05, 2007 @05:24PM (#20873683) Homepage
    Does this mean Mr. Graves is the world's first man-made chimera [wikipedia.org]?
  • by corsec67 (627446) on Friday October 05, 2007 @05:30PM (#20873789) Homepage Journal
    Like this: http://en.wikipedia.org/wiki/Lydia_Fairchild [wikipedia.org]

    Summary: Woman is a Chimera (two sets of DNA), and gets a paternity test, first one fails, second succeds because they take from another part of her body.
  • by Anonymous Coward on Friday October 05, 2007 @05:35PM (#20873859)
    Or you could just NOT bleed all over the crime scene...
  • in that episode, there was a man who cleverly attempted to avoid culpability in a murder because his blood was a different genotype than the rest of him, because he was a chimera [wikipedia.org]. the csi team spends much time in vain trying to pin the murder on the murderer's brothers, because genetic tests indicate he is related to the "real" murderer

    real but extremely rare, it developmentally consists of nonidentical twins in the womb whose embryos fuse very early on, when that is still possible (when they are only a couple of hundred cells, for example)

    then the organism consists of one individual, but one organ system might be a completely different genetic makeup than another organism. so sombody's nervous system could be genetic code A, while his spleen could be genetic code B. chimeras can go through life having no idea what they are, but sometimes, you can see it on their skin (a subtle zebra striping)

  • by MyrddinBach (1138089) on Friday October 05, 2007 @06:14PM (#20874241)
    Watch the Documentary from Discovery channel titled "I am my own Twin"

    This happens naturally in lots of people.

    It even touches on the subject of pigmentation - where babies of interracial couples are born with "checkberboard" skin.

  • by edwardpickman (965122) on Friday October 05, 2007 @06:26PM (#20874337)
    What this shows is that a true Chimera is possible mixing human and foreign DNAs. It's amazing that multiple DNA sequences can be supported by the body. Rejection becomes an issue but I'm curious if the body would be more accepting for foreign tissue if it's producing the tissue. The immune system obviously isn't designed to detect foreign DNA but the tissue the DNA is producing is foreign. I'm just curious how far this process can be taken before rejection becomes an problem?
  • by CustomDesigned (250089) on Saturday October 06, 2007 @09:54AM (#20879095) Homepage Journal
    Everyone has multiple sets of DNA. Some of your mothers stem cells migrate to your body before and during birth. There, they been documented to become immune cells, heart cells in the case of an infant with a weak heart, and other needed parts to help an infant survive. The average person has about 50 million of his mothers cells still alive in his or her body in adulthood. The chances of this affecting a standard DNA sample are infinitesimal, of course. However, 1 in a million adults is a chimera, with significant portions of alternate DNA. Sometimes, twin embryos merge instead of developing separately - the ultimate siamese twin [telegraph.co.uk].

    This leads to heartbreaking legal situations. A mother applied for welfare benefits. When they did DNA testing to make sure the kids were hers, DNA testing showed half were not, and they took half her kids away. Her obstetrician and her husband testified under oath that they had observed the kids birth, but to the bureaucracy, DNA was incontrovertible. Years later, a doctor interested in chimerism noticed her case, took multiple DNA samples from many locations, and showed that she had 2 major and one minor DNA profile. The minor was her mother, the 2 major profiles were her and her fraternal sister. The embryos had merged, and half her eggs were one DNA and half her sisters (or vice versa - it's hard to say if it's her or her sister).

    A winning athlete was accused of blood doping (blood transfusion before the competition to increase stamina) and lost his medal, despite medical testimony that he was a chimera, and had two types of bone marrow DNA, and hence two types of blood.

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