This is a test version of Biostars. For the public version, visit https://www.biostars.org.
generating genome indexes with STAR

Hi, I am trying to generate mouse geneome indexes with STAR to align my RNAseq data. I downloaded the mm10 genome in tar.gz format (Mus_musculus_UCSC_mm10.tar.gz). Do I have to gunzip this first before trying to index the genome? Thank you!

rna-seq star

3 answers

Yes, you'll need to untar it first.

Thanks so much! After untar-ing when I tried indexing, I don't think it worked.

The command used:

STAR --runThreadN 4 --runMode genomeGenerate --genomeDir Genome_data/star \
--genomeFastaFiles Genome_data/Mus_musculus_UCSC_mm10.tar.gz

Result: Jun 23 14:20:03 ..... Started STAR run Jun 23 14:20:03 ... Starting to generate Genome files Killed: 9

I don't think it was indexed. Do you know what the problem might be?

STAR is known to require plenty of RAM (30+G) for operations. How much memory do you have access to?

You are still using the tar archive for the fasta files. Use the fasta files extracted from the tar archive

You can try the following:

STAR --runThreadN 4 \
--runMode genomeGenerate \
--genomeDir /path/to/genomeDir \
--genomeFastaFiles /path/to/genome/ref.fasta \
--sjdbGTFfile /path/to/annotations.gtf \
--sjdbOverhang 149

--sjdbOverhang is ReadLength-1

I had the same problem, for me it was becuase I was using a database of all human viruses as opposed to a genome. This had too many contigs, I read in a google post to increase the genomeChrBinNbits 14, that did it.

Log in to answer this question.