Previous qPCR test on pooled samples determined these 4 primers would be run on known samples. Ran qPCR as previously described.
Results from qPCR on known samples:
Two runs had to be done to be able to include all samples.
Results
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- contamination in no template controls (NTC)
- unknown when contamination could have occurred
- Water used for NTC seems unlikely since similar amplification is occurring in each sample
- Possible contamination in primers, master mix, or DNase
- Tris-EDTA added to lyophilized primers?
- used 2017 DNase for RT
- Tris-EDTA added to lyophilized primers?
- unknown when contamination could have occurred
- contamination in no template controls (NTC)
Regardless, there is non-specific amplification which also occurred in the last qPCR run on pooled samples.
The non-specific binding could instead be the presence of leftover DNA from a less effective DNase (since it was from 2017). In order to test this:
-
- one RNA sample left (G38) that hasn’t been DNased
- run qPCR on 4ng RNA from G38 (equivalent to RNA amount run in previous qPCRs)
- Include NTC to test if primers are contaminated as well
- run qPCR on 4ng RNA from G38 (equivalent to RNA amount run in previous qPCRs)
- one RNA sample left (G38) that hasn’t been DNased
I can dilute my cDNA 1:10 to try to make it last longer which can be seen in amplification image. I used up a substantial portion testing the 4 selected primers during these runs.
Next, Sam suggested I run pooled samples at a gradient of temperatures to identify an ideal temperature with reduced non-specific binding.