possion distribution of ChIP-seq

Question

[Ben]

I want to use MACS to call peaks, the MACS used possion distribution to detect significant peaks. Does anyone know how to used possion distribution to detect peaks?

[Ram]

It is spelled "Poisson", with the capital P :)

[PoGibas]

You never know: https://www.ncbi.nlm.nih.gov/pubmed/?term=possion
"Multivariate possion regression analysis was applied ..." :)

Answer 1

[Devon Ryan]

It's generally presumed that a background (either an input sample or non-enriched regions) will have signal following a Poisson distribution. Consequently, one can track the lambda from that (see the --llocal and --slocal options) see if a given spot has siginificantly more signal than expected given that distribution. This is then given a p-value accordingly and you have your peak.

Edit: The wiki from MACS2 may be helpful.