DNA ladder - A template for copying the Whole
Because of the obligatory
pairing of adenine-to-thymine and guanine-to-cytosine,
Watson and proposed that one half of the DNA ladder
serves as a template for recreating the other half
during DNA replication.
By 1958, two lines of evidence
can be together to provide proof of this hypothesis.
First, an enzyme was discovered-DNA polymerize-that
adds complementary nucleotides to the template provided
by a half DNA molecule.
Second, an ingenious
experiment used nitrogen isotopes to fellows the
construction of new DNA molecules during successive
generation of bacteria, This showed that one strand
of each NA molecule is passed along unchanged to
reach two daughter cells.
This "conserved "
strand acts as the template for DNA polymerizes
to synthesize a 2nd complementary strand, which
completers each new DNA molecule.