Bulk RNA-Seq Read Length Normalization across different samples I have 20 samples out of which 14 are 100 bp in length and 6 are 150 bp. Is there a way to normalize the read length for cross-sample differential expression comparison? What would be the best way to approach this?
Note: The samples are NOT from reference/model species.
The simplest thing to do is to trim the 150 bp fasts so that they are 100 long.  I don't think there is an easy way to correct for the fact that the 150 bp long reads will have a higher unambiguous rate of alignment and gene assignment than the 100 bp long reads.
If you have a mix of all the experimental conditions across all the lengths, you can include length as an element in the design, so that DESeq2 may be able to model the difference between the two batches.