The Polymerase Chain Reaction
(PCR) in detail
The first round of PCR in step (c) generates two long
fragments that run off the 5'
ends of the target region. In the second round in step (e), extension again
generate variable length strands. Thus,
the first two rounds of PCR
not generate short DNA products
to the interval between the primers. Only in the third round in step (g) are 'unit length' products
generated uniformly for the first time.
Compare the process illustrated in this
diagram with that in the simplified
which shows the process as it works beginning in the fourth
round of amplification.
Figure ©2002 by
Griffiths et al. ; text ©2014 by Steven M. Carr