DESeq2:Why is there an oblique line in my MA picture, which happened before, what caused this?
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@xuyao15927402897-20826
Last seen 17 days ago
Germany

My sample is RNA-Seq data from human Esophageal tissue, 9 control groups（normal）, 2 experimental groups（Esophageal cancer），The result is Figure 1.

I use featurecounts to count genes, this is my counts array

deseq2 cancer • 345 views
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@mikelove
Last seen 1 day ago
United States

Those lines are from genes with very low counts of genes, e.g. 2 counts in the treated group, 1 count in the control group. If you want to remove them you can perform some minimal filtering, e.g.:

keep <- rowSums(counts(dds) >= 10) >= x
dds <- dds[keep,]


Where you choose x to be a small number of samples.

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Will removing these low counts have any bad effect, will I ignore the low-expression genes?

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It's pretty hard to achieve power for DE when there are say, only 2 samples with counts above 10. So setting x <- 3 will be fairly conservative in terms of FNR.

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Ok, thank you very much！