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DNA mismatch repair

  1. Nov 11, 2011 #1
    i understand that methylation helps to differentiate between parental strand and daughter strand with mismatch nucleotides. (newly synthesised DNA is hemimethylated)
    then GATC endonuclease and GATC exonuclease will nick the mismatch nucleotide sequences.

    however, i don't understand how the faulty daughter strand are distinguished from normal daughter strand?
  2. jcsd
  3. Nov 11, 2011 #2


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    What is recognised is the mismatch surely? A distortion of the normal DNA double helix.

    What text are you working from and does it not say that somewhere?

    And is it talking about a bacterial system (6-adenine) or mammalian (5-cytosine) methylation system?

    If there is a mismatch the enzymes could not distinguish which strand was 'right' i,e, parental and which 'wrong' i.e. daughter without the methylation.
    Last edited: Nov 11, 2011
  4. Nov 11, 2011 #3


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    In DNA replication you start out with one double stranded DNA consisting of two parental strands. After replication, you have two double stranded DNA and each of these DNA molecules contains one parental strand connected to one daughter strand. Therefore, you don't need to distinguish between daughter strands as they are on different molecules of DNA.
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