DNA replication

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DNA replication recombination
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Semi-conservative replication
Klug, Cummings Spencer, 2006
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Klug, Cummings Spencer, 2006
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The Meselson-Stahl experiment
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Semi-conservative replication in Eukaryotes
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DNA replication
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In eukaryotic DNA replication begins at
numerous sites replicons
Proceeds in both directions from each replicon
until neighboring replicons fuse and all of the
DNA is duplicated
Passarge, 1995
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A new nucleotide cannot be attached at the 5-OH
end of the new nucleotide chain only at the 3
end.
New DNA can be formed continuously in the 5 to
3 direction but NOT in the 3 to 5 direction
Klug, Cummings Spencer, 2006
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DNA replication process
STEP 1 The DNA helix must be unwound
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STEP 2 Initiation of DNA synthesis requires an
RNA primer
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STEP 3 Antiparallel strands require continuous
and discontinuous DNA synthesis
Passarge 1995
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Along the 3 to 5 strand - lagging strand new
DNA is formed in small segments of 1000-2000
bases (Okazaki fragments)
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Proofreading and error correction
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