I have a question regarding the MEDIPS.meth output. I have 2 data sets (no replicates) and I would like to get the differential methylation coverage between them. I undestand that the log2FC are calculated: log2 (Mset1-Mset2) but when I check the output I see that in some cases I got log2FC<0 when the counts are higher in Mset1 than in Mset2. So I wonder how is it calculated? using normalised counts?
Code should be placed in three backticks as shown below
mr.edgeR <- MEDIPS.meth(MSet1 = bam_clon,
MSet2 = bam_wt,
CSet = CS, #COUPLING SET
p.adj = "bonferroni",
diff.method = "edgeR",
MeDIP = T,
minRowSum = 10,
CNV = F,
diffnorm = "tmm")
# and this is the output
mr.edgeR[105:106, c(1:10,15:20)]
chr start stop CF H827_12.bam.counts H827_wt.bam.counts H827_12.bam.rpkm H827_wt.bam.rpkm H827_12.bam.rms H827_wt.bam.rms
105 chr1 10401 10500 6 14 9 1.90 1.44 0.29 0.25
106 chr1 10501 10600 7 6 5 0.81 0.80 0.22 0.21
MSets2.rpkm.mean MSets2.rms.mean edgeR.logFC edgeR.logCPM edgeR.p.value edgeR.adj.p.value
105 1.44 0.25 0.29504070 -4.564983 0.6778166 1
106 0.80 0.21 -0.07439969 -5.406249 1.0000000 1
#In lane 105 with Mset1 counts > Mset2 counts I get a log2FC > 0
#In lane 106 with Mset1 counts > Mset2 counts I get a log2FC < 0
I´m guessing there is some normalisation underneeth that I am not aware of and that would be the reason for that.. I would appreciate your help with that. Thanks!!