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From a DNA extraction procedure description (an in-house pharma document I'm translating into Russian):

Preparation of Standards

  • All the standard reactions should be prepared at least in duplicates. The template DNA stock (CHO cell genomic DNA) should not be less than 100 ng/μL concentration.

Does "standard reactions" here mean what it says, or does it really mean "reactions with standards" (reactions using standard samples)?

P.S. It is part of a qPCR procedure to quantify host cell DNA content. The company is producing a monoclonal antibody drug and is describing its internal procedures. As a translator I cannot disclose the document in full.

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In order to quantify a target using real-time PCR, each run must include a standard curve of your target DNA. This is typically done by making serial dilutions of some known quantity of template DNA, with each dilution assayed in duplicate or triplicate on the same plate as your experimental samples of unknown quantity. A standard-curve is also important for determining assay validation statistics like amplification efficiency (reference).

Does "standard reactions" here mean what it says, or does it really mean "reactions with standards" (reactions using standard samples)?

Since your protocol is designed to quantify host DNA, I would interpret the phrase "standard reactions" as referring to the actual qPCR reactions containing standard dilutions, not necessarily to the DNA extraction procedure. The reason there is a specified minimum concentration for the standard template DNA is likley a quality control check to prevent errors caused by degradation of DNA standards during storage or from freeze-thaw activity. The quality of your qPCR data can only be as good as the quality of your standard curves.

Reference:

  • Real-time PCR Handbook, published by ThermoFisher Scientific (Lifetechnologies.com)
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Is this PCR or just DNA extraction and if so, what is the source material?

If it is just DNA extraction, maybe the standard reaction means to extract some given standard sample DNA (CHO cell genomic DNA?) to optimise the yield and reaction conditions.

You would ideally use these same reaction conditions to extract other genomic DNAs.

Also, is the CHO genomic DNA included in the kit?

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  • $\begingroup$ It is part of a qPCR procedure to quantify host cell DNA content. The company is producing a monoclonal antibody drug and is describing its internal procedures. $\endgroup$
    – CopperKettle
    Jul 4 '20 at 3:18

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