EdgeR, only 1 DEG between 2 groups, Is it necessary to remove non-coding RNA before DEG analysis?

Question

[TM]

I am doing gene expression profiling of 3 structures(A,B,C). I compared (A vs B&C), (B vs A&C), (C vs A&B). I found 1, 2 and 20 DEG respectively between groups comparison. Are there any problems with these results, do I need to remove non-coding RNA before DEG analysis? I tries to find document and script to do so but I couldn't find one. Can you help me solving these problems?

Answer 1

[ATpoint]

Is it necessary in terms "must I do it" => no

Can it be helpful, yes. If you have low power and/or much dispersion and/or low sample size (that all is basically interconnected) then removing genes to lower the multiple testing burden can help. You could run filterByExpr() first, then do the testing and then remove all but the non-coding genes before calling topTags(). Be sure to do a QC, e.g. by PCA or MDS (see edgeR manual) to see why you have few DEGs.

[TM]

Thanks for your comment, could you tell me the function to remove non-coding gene ?