edgeR: How is FDR calculated for logFC? (False Discovery Rate)
1
0
Entering edit mode
jol.espinoz ▴ 40
@jolespinoz-11290
Last seen 3.1 years ago

I'm having difficulty conceptualizing how significance of logFC is calculated with `exactTest()` and `Benjamini-Hochberg` adjusted FDR calculation with `topTags()`.  

Let's say you had `100 genes` with `5 control replicates` and `5 experimental replicates`,  how are p-values for the logFC calculated and then how are they adjusted using the `Benjamini-Hochberg` method?  For example consider `gene_1`, what if the control samples for `gene_1` were: `u = [5, 6, 5, 7, 5]` and the experimental replicate samples for `gene_1` were: `v = [9, 10, 11, 10, 8]`.  Does the algorithm just do a t-test or wilcoxon between `log2(u)` and `log2(v)` to get the p-values?  If so, wouldn't you need quite a bit of samples to get a reliable p-value? 

Is this how the p-value is calculated? If so, how the FDR calculated from this?  Sorry for all the questions, I'm just having trouble visualizing it.  I just ran `edgeR` on a dataset with 3 control replicates and 3 experimental replicates.  I'm not sure how the p-values and the FDR values are calculated and I'm trying to avoid blackboxing (i.e. using algos I don't understand conceptually).

edgeR bioconductor fdr statistics differential gene expression • 7.7k views
ADD COMMENT
2
Entering edit mode
@james-w-macdonald-5106
Last seen 1 day ago
United States

There's no need to 'blackbox' anything. There is a user's guide that explains all, along with references if you really want to get down to the nitty gritty.

ADD COMMENT
0
Entering edit mode

Thanks for that!  So does it use a negative binomial distribution of the controls and then find the likelihood of the experimentalsnto fit that model? 

ADD REPLY

Login before adding your answer.

Traffic: 457 users visited in the last hour
Help About
FAQ
Access RSS
API
Stats

Use of this site constitutes acceptance of our User Agreement and Privacy Policy.

Powered by the version 2.3.6