converting log-odds ratio to p-value in HOMER

Question

[sumithrasank75]

I used scanMotifGenomeWide.pl for a certain motif and the output is a bed file which reports the log-odds score for finding the motif at a given chromosomal location. I want to know how to convert the log-odds ratio to a p-value so that I can filter the bed file by a p-value cutoff. Thanks

[Fabio Marroni]

A quick google search led me to an online tool for computing p-values from log-odds, and to a nice blog showing how to perform the computation in R. Not being an expert on the topic, I do not know if they are formally correct. But on a fake example they gave the same result!