My lab is going to work on ATAC for the first time and I have been asked as to what is amount of sequencing we need to do. We want to end up with 50million aligned reads. So my question is what is the ballpark mapping rate that is observed for ATAC data. We are planning on doing 100bp paired-end reads.
My search led to this post where it seems the mapping rate can vary between 50% to 90% (https://www.biostars.org/p/170294/). Any further light on what is generally seen would be helpful.
It has varied for me from study to study. A study we did in dogs had an alignment rate of 50-55%. While, another study we did in xenopus tropicalis had an alignment rate of 80-90%. It's unlikely that the organism has anything to do with these results, but just showing the variety of data we have gotten. I posted a question about this a while back that I think would be good for you to read. We discussed a lot of the pitfalls and problems one can come across when looking at ATAC output. C: What is the reason for trimming reads to 30 bp for ATAC-seq aligning?
Lastly, it's important to remember that a large proportion of your reads will align to the MT region. There are newer methods (example) that can deplete these reads depending upon your needs.
What species are you working with?
We think it will be mouse.