This is a test version of Biostars. For the public version, visit https://www.biostars.org.
Computer requirements for RNAseq alignment

Hi,

I plan on analysing the following RNA seq data: cca 30M reads/sample, 15 samples, human data. The aim is to do differential expression analysis. I plan to perform alignment with HISAT2 and I wonder if my computer (specifications below) suitable for this?

  • Processor: Intel(R) Core(TM) i7-4790S CPU @ 3.20GHz, 3201 Mhz, 4 Core(s), 8 Logical Processor(s)
  • Installed Physical Memory (RAM) 16,0 GB
  • HDD: WD Blue PC Desktop Hard Drive (WDC WD10EZEX) - 1TB
  • SSD: Crucial BX100 SSD (CT1000BX100SSD1) - 1TB

If not I, what would my best option be - additional RAM (how much?) on this computer, different alignment tool, cloud computing (like AWS), galaxy?

Any input or experience is helpful! Thanks, Nina

rnaseq alignment computer hisat2

AFAIK, HISAT2 is the best alignment tool for low RAM. 1 TB is way enought to stock your data and output data. I would say, give it a try and if the alignment step failed, look at the output error to know if it is a memory issue or something else. If it is a memory issus you can try to add more RAM or run your alignment under a cluster. I have no experience with galaxy.

2 answers

You could use kallisto : https://pachterlab.github.io/kallisto/about . It uses minimal RAM with similar sensitivity as more "standard" "align-then-count" methods. In general less than 4Gb RAM per sample is required

From kallisto website :

On benchmarks with standard RNA-Seq data, kallisto can quantify 30 million human reads in less than 3 minutes on a Mac desktop computer using only the read sequences and a transcriptome index that itself takes less than 10 minutes to build.

For human genome you need ~30G of RAM for STAR/BBmap (if you are staying with alignments). So it would be advisable to get at least 32G. If you are able to use mapping type methods (noted by @Nicolas) then you could use your present config.

it would better say pseudo-mapping or pseudo-alignment tha mapping methods ;)

Log in to answer this question.