I am reading an article for my class presentation and have attached the pubmed link with this http://www.ncbi.nlm.nih.gov/pubmed/27292631
I have several questions on Fig 2A from the article, which is the global chip-seq data for H3K4me3 in the TSS. It would very helpful if someone elaborate on how they obtain the figure and what represents the x and y axis.
Also, there is a drop in the H3K4me3 at the TSS, which contradicts the fact that H3K4me3 is abundant near TSS and is a mark of active transcription. Why there is a lower methylation at the TSS and there is higher methylation at the upstream and the downstream of the TSS.