Question #a3407

1 Answer
Stefan V.
Feb 11, 2015

I think that the program uses too little exposure time for the last step of the polymerase chain reaction, or PCR.

In order, the steps that must be taken in order to obtain a successful amplification are:

  • Denaturation
  • Annealing
  • Primer extension (or elongation)

Primer extension is done by heating the DNA template to temperatures ranging between #70# and #80^@"C"# - usually at #72^@"C"# - for a period of time that depends on how long your DNA sequence is.

In this step, new complementary DNA strands are synthesized by DNA polymerase.

As a general rule, you get approximately 1 minute of exposure for every 1000 bp of DNA. For your sample, this would mean a total of approximately 2 minutes, not 30 seconds as the program uses.

Here's another video on the process:

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