How to downsize my 4Go FASTQ file to an 1Go FASTQ file?

Hi Galaxy community,
I’m new here and first of all I’m absolutely not into bioinformatics and coding, everything is quite new to me! I’m trying to upload my fastq files here to first see if my sequences are good enough to work downstream. My files are 4Go and I would like to “cut” them into 1Go files - without any trimmering. Could anyone help me? Thanks a lot!!

Welcome, @dhebinger

There are a few ways to downsample a fastq files. These two tools are good basic options.

  • Sub-sample sequences files e.g. to reduce coverage
  • seqtk_sample random subsample of fasta or fastq sequences

Search the tool panel at the UseGalaxy server where you are working at to find these, then scroll down on the tool form itself to reach tutorials with examples.

For the quality assessment steps, a tutorial like this one might be helpful if even just as a reference. These tools can definitely process a full 4 GB fastq file if that would be interesting to you, along with the smaller file chunks.

And finally, if you are not familiar with all of the different types of fastq files, or not sure how those are labeled and used with tools in Galaxy, this quick guide is a great resource!

If I misunderstood, and you need to create smaller files because you are having trouble getting the data into Galaxy, please clarify and we can offer more help. This guide is also a good summary with link-outs to advanced strategies.

Let’s start there, thanks! :slight_smile: