Thanks, GenoMax. Do you know how to use the output of pre-alignments by bowtie2 as an input file for alignments like below? Or Should I use some package like SamToFastq and use this output for 2nd round bowtie2?
bowtie2 -k 1 -D 20 -R 3 -N 1 -L 20 -i S,1,0.50 -X 2000 --rg-id \
-x GRCm39 \
-1 pre_1.fq.gz \
-2 pre_2.fq.gz \
-S pre.sam
bowtie2 --very-sensitive -X 2000 --rg-id \
-x GRCm39 \
-1 pre.sam \
-S filtered.sam