Primer-DNA RNA?

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student12
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Primer-DNA RNA?

Post by student12 » Mon Jun 12, 2006 7:53 am

In my text relating to DNA replication it refers to the RNA primer. However, relating to PCR-DNA amlification it refers to the DNA primer.

First of all why is this the case - DNA relpication:RNA primer, PCR:DNA primer?
Secondly when I look at the definition for a primer - it states that it is an RNA stand...so what's with the DNA primer?

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canalon
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Post by canalon » Mon Jun 12, 2006 2:15 pm

In DNA replication, RNA primers are sythesized by an RNA polymerase which can start the synthesis of a nucleic acid with just a template and no primer. No DNA polymerase can. But they could start with DNA primers if such thing was available (and they do when repairing DNA).

When scientist are doing PCR they use a DNA polymerase,and it nedd a primer. RNA primers could be used but they are unstable and Rnases are frequent and really hard to get rid of, while DNA is easy to synthesize artificially and is way more stable. So when we are working in vitro, the use of DNA is for convenience.
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