Eukaryotic DNA replication: a model for a fixed double replisome.

To duplicate their genomes, eukaryotic cells have to overcome some formidable chemical and topological hurdles, considering the number of nucleotides that have to be polymerized faithfully and the sheer physical size of the DNA molecules that have to be disentangled and partitioned in an orderly way. This article tackles one particular aspect of the process: the organization of the apparatus that advances the replicative growing forks along the DNA molecule. Here, I suggest a solution to the difficulty of separating the daughter molecules in an orderly way and propose an alternative to the current models, which reconciles the use of a single polarity of synthesis by the DNA polymerases with the need for parallel polymerization of two strands of opposite polarity.