Tuesday, 1 July 2008

biochemistry - How do multiple replication forks function without 'colliding', and what is the benefit of this method?

I'm currently reading a little about DNA replication, and have come accross the following statement;




Replication starts from a fixed point and is bi-directional ... In Eukaryotes, there are multiple replication forks, each progressing in a bi-directional fashion.




If there is a single, long strand of DNA in a Eukaryotic cell, I see potential problems with this:



These forks involve opening up a section of double-stranded DNA, and each strand becoming a double strand in a newly synthesised piece of DNA. At some point, before any single fork has become two new double-stranded molecules, another fork could 'collide' with this, causing it to attempt to replicate the non-finished section.



Simply, how can one replication fork meet another without either exponentially increasing the number of strands being replicated?



Also, on a more general level, I would be quite interested to know the actual benefit of this, when, typically, only a single copy of the double-stranded molecule needs making.

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