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is "quant_reading" DNA concentration in some units or total DNA

Open Rob-murphys opened this issue 1 year ago • 5 comments

I am confused if quant_reading in the introduction is total DNA or DNA concentration in some units. If so are there any specific units?

I have the issue of having some samples which did not have enough DNA for sequencing before pooling. So I re-PCRed those samples and pooled them all or partially together and am wondering how I then give a final value to decontam for my concentrations?

Rob-murphys avatar Apr 25 '23 12:04 Rob-murphys

The units don't matter as long as its the same units throughout. In other words, only the relative DNA concentrations are used by decontam, not the absolute values.

benjjneb avatar Apr 25 '23 14:04 benjjneb

Okay thank you :)

What should I do for samples when I had to pool PCRs? (A stupid question I know but I can't find a solid answer on how to handle that)

Rob-murphys avatar Apr 25 '23 14:04 Rob-murphys

What should I do for samples when I had to pool PCRs?

At what step are you measuring DNA concentrations? If you measured before you pooled separate PCRs into a common sample, then sum those measurements. If you measured after pooling separate PCRs into a common sample, then use as the measured DNA concentration as is.

benjjneb avatar Apr 25 '23 19:04 benjjneb

I measured before pooling but when pooling I did not always take the same volume. For example it may have been 40 ul of one and 8 ul of another to make the total DNA reach the acceptable sequencing threshold. Can I still just sum them?

Rob-murphys avatar Apr 26 '23 08:04 Rob-murphys

However you did your sample combination, you want the number of the combined sample to represent the same type of number as you measured in the other samples. Assuming these are all in terms of DNA concentrations, then I guess your combined samples are some sort of weighted average of the concentrations in the original samples that were combined.

benjjneb avatar Apr 28 '23 18:04 benjjneb