Replicating
Forks
At a point where the two strands are separated a replicating fork is formed. The fork appears in the form of a Y and advances during replication. In bidirectional replication the separated strands between the two forks appear as a 'bubble' or an 'eye' under the
electron microscope.
The speed or extent of movement of the two forks in opposite directions need not be the same.
In E. coli there are generally two replicating forks, while in eukaryotes there may be several thousand. The large number of replicating forks in eukaryotes is due to the fact that replication begins simultaneously at many points along chromosomal DNA.
