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  1.  (1368.1)
    Identical twins apparently do not have identical DNA.

    “When we started this study, people were expecting that only epigenetics would differ greatly between twins,” said Jan Dumanski, a professor of genetics at the University of Alabama at Birmingham and an author of the study. “But what we found are changes on the genetic level, the DNA sequence itself.”
  2.  (1368.2)
    Ah, ah, proof! I always thought that it would make sense for someone's genetic make-up to actively change during their life span. I guess this has ramifications for natural selection as a process?
    • CommentAuthorStefanJ
    • CommentTimeMar 12th 2008
    This is going to totally muck up any number of CSI episodes.
  3.  (1368.4)
    I guess this has ramifications for natural selection as a process?

    Yes. This will be very interesting to see who makes the connection and how it unfolds in the news.
  4.  (1368.5)
    exciting :D
    I've always hated the nature vs nurture argument for being too polarised, and this throws a big spanner into the workings. Imo, nature and nurture is evidently a self-influencing circular process.
    • CommentTimeMar 12th 2008
    Yeh it's like any argument where it's X or Y, clearly it's neither one nor the other, it's a mix of both.

    And CSI is full of nonsense anyway I'm told.
  5.  (1368.7)
    Imo, nature and nurture is evidently a self-influencing circular process.

    My thoughts too. Some people are really not going to like this article.
    • CommentTimeMar 12th 2008 edited
    Someone please correct me if I'm wrong, but from what I understand, don't identical twins have identical DNA in terms of what genes they actually possess, but they can differ to quite an extent in terms of how, to what extent, or if at all, those genes are expressed depending on differing environmental and developmental pressures?
    • CommentAuthorKosmopolit
    • CommentTimeMar 12th 2008
    T.B. this article is saying that even supposedly identical twins actually do have slightly different genes - not just different patterns of gene expression (or epigenetics as its referred to in the article).

    Off the top of my head, I suspect these differences are probably caused by minor mutations during cell division in the early stages of pregnancy after the original embryo splits to form the twins.
    • CommentAuthorkozmund
    • CommentTimeMar 13th 2008
    To me, the really interesting part here is not that grown, identical twins have non-epigenetic differences. The really interesting part is that identical twins are being shown to be a good tool for studying how and where copy number variations (CNVs) contribute to disease. CNVs are a little more involved than a simple hand-waving mutation. Most likely there's some hints in there about other things, but the big part seems to be right there.

    It's been supposed for by various researchers, to various extents, for various reasons, that identical twins aren't. Identical. As I understand it, the fact that this is the first study to show that fact is closely linked to the fact that this is one of the first times that knowing that for sure would be applicable to genetic diseases.

    With any luck, this will lead to more full sequencing of identical twin pairs so that the genetic variation caused by things like retrotransposons can be studied from the same data. But hey, who wants to drop the fat grant cash on that sort of thing this early, just so that studies on a tiny portion of our genome can be properly correlated with studies of what's going on in the rest of the genome. Right?

    Fine, fine. I have some sort of NIH budget hobbyhorse. I admit it.