Volcano plot from Posterior probabilities instead of p-value

Question

[Thibault D.]

Hi !

I'm currently diving into isoforms differential expression analysis results. I use the duo RSem-EBSeq to perform this work. I'd like to build a volcano plot of my data.

RSem-EBseq returns posterior probabilities (PP) and no p-values (PV) at all. I am aware, that both PP and PV allows me to answer the same question. I know that PP goes from 0 the lowest probability to 1, the highest. So I could just multiply those values b -1 to have a volcano plot in the same orientation as a "classic one".

Is it acceptable to do such a thing ?

[WouterDeCoster]

It sounds valid to me to use the PP, but I'm not sure what you mean whit "classic one" and orientation.

[Thibault D.]

If I do not multiply by -1, the volcano plot with PP would be reversed horizontally: the maximum value would be 0, the worst PP