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What are the disadvantages of increasing the sequencing depth of RNA-seq experiment?

I am designing an RNA-seq experiment to study a region of the mouse brain. I am particularly interested in the Orexin system (set of rarely expressed genes). I have the option to sequence at a depth of 60 Million Paired-end reads or 100 Million paired-end reads. From what I have read, I realize that iIshould increase my sequencing depth. (I have decided to have 3 biological replicates from cases and 3 biological replicates from controls.)

If I increase the sequencing depth (say 100 Million Paired-End), will there be any disadvantages that I did not foresee? can this become computationally cumbersome to analyze? I am using a cluster of 64 nodes.

I would really appreciate it if I can get your experienced opinion about this.

ngs rna-seq sequencing depth transcriptome

Seconding the below answer. Sure a good depth is important for lowly-expressed genes but these have low statistical power due to low counts. If you can then do more replicates to gain statistical power, see http://m.rnajournal.cshlp.org/content/22/6/839.full The gain of power is especially notable if you do like four or five rather than two or three replicates. 60M is enough in most cases.

Thank you ATpoint. Thanks for the reference and suggestion.

1 answer

Fastq length doesn't matter like genome size does. I would give some thought to whether you'd be better off with more replicates, even if they are at lower depth.

Thank you swbarnes2

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