Genetics
DNA replication
DNA replication is the process in which a cell’s entire DNA is copied, or replicated. The identification of
the structure of DNA suggested that each strand of the double helix would serve as a template for
synthesis of a new strand. DNA replication process occurs during the Synthesis (S) phase of the eukaryotic
cell cycle. As each DNA strand has the same genetic information, both strands of the double helix can
serve as templates for the reproduction of a complementary new strand. The two resulting double
helices, which each contain one "old" strand and one "new" strand of DNA, are identical to the initial
double helix. DNA replication is said to be semi-conservative because of this process of replication, where
the resulting double helix is composed of both an old strand and a new strand.
The semi-conservative mechanism of replication was one of three models originally proposed for DNA
replication:
Semiconservative replication
would produce two copies that
each contained one of the original
strands and one new strand.
Conservative replication would
leave the two original template
DNA strands together in a double
helix, with the new DNA composed
entirely of two new strands.
Dispersive replication would
produce two copies of the DNA,
both containing a mixture of old
and new material.
