DaehwanKimLab / hisat2

Graph-based alignment (Hierarchical Graph FM index)
GNU General Public License v3.0
464 stars 113 forks source link

Aligning Ribo-seq reads using hisat2 #329

Open zhiyi1988 opened 2 years ago

zhiyi1988 commented 2 years ago

Hi there,

I need to align several libraries of Ribo-seq reads that are on average 30 nt long to a genome of about 2Gbp. I'm using the following parameters currently, Indexing: ../hisat2-2.1.0/hisat2-build --ss ss.txt --exon exon.txt genome.fa index_prefix

Mapping: ../hisat2-2.1.0/hisat2 \ -x index_prefix \ -k 200 --phred64 --mp 1,1 --score-min L,0,-0.1 \ -U input_1.realclean.fq.gz -S output_riboseq.sam

The overall alignment rates are around 30%-40%. So in order to increase the alignment rate, are there any recommended special parameter values that I should use in generating the index and in running the hisat2 alignment with such short reads?

Thanks for hisat2 and for any suggestion!

Best regards, Zhiyi