About ATAC-seq peakcalling
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Hi
Genrich is a wonderful tool for ATAC-seq data. I have used it in my cell metabolism paper (DOI: 10.1016/j.cmet.2021.06.004). And I'll used it again in my new project.
I have one question about the peak calling. I was told by other senior analyzer that only nucleosome-free (NFR) reads should be considered for peak calling. Does Genrich containing steps to remove Mono nucleosome reads and Nucleosome reads, and do peak calling only using nucleosome-free (NFR) reads?
Thanks for the question. There is no option in Genrich to filter fragments based on size. While it is true that ATAC-seq fragments follow a characteristic size distribution, it is not the case that all fragments above a certain size (~150bp) are derived from DNA segments surrounding one or more nucleosomes. I do not know of a method to separate reads derived from longer fragments into those that surrounded nucleosomes versus those that did not.