Hello, I need some help with deciding the best way to present data. I have UNT and treated samples between a control and knock-out sample. I currently have the data presented as normalised gene counts in a heatmap, as I think this better represents what’s going on in my samples. Whenever I do log2FC I feel like it hides a lot of data and is not telling the true story. Is it okay to present normalised gene counts in a heatmap? Thank you.
2 answers
It is absolutely fine to present normalised gene counts. The most common way that we present data is median-scaled gene counts (gene-wise centering by the median). In R it would be something like:
centred.matrix <- assay(rlog.dds.object) - rowMedians(assay(rlog.dds.object))
In the Deseq2 workflow section 4.3 (Sample distances) you can see (with coding) how to normalise, calculate sample distances, and plot the heatmap "to assess overall similarity between samples: Which samples are similar to each other, which are different? Does this fit to the expectation from the experiment’s design?"
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its arguably even better than presenting log2FC. you can ballpark a log2FC from counts, reverse isnt true.