chipenrich

ChIP-Enrich is a sophisticated method designed to facilitate gene set enrichment testing for ChIP-seq data, enhancing the biological interpretation of the results. Recognizing the impact of gene locus length (encompassing both the gene body and adjacent non-coding sequences) on the likelihood of identifying one or more peaks within a gene set, ChIP-Enrich introduces an empirical adjustment for this factor. This adjustment is crucial as gene locus length is often positively correlated with peak presence, and many biologically defined gene sets disproportionately contain genes with either longer or shorter gene locus lengths.

Distinct from other gene set enrichment methods, ChIP-Enrich can accommodate the diverse relationships between gene locus length and peak presence observed in ENCODE ChIP-seq datasets. Through evaluations using permuted ENCODE ChIP-seq datasets, ChIP-Enrich demonstrated a well-calibrated type I error rate, in stark contrast to the inflated error rates and bias encountered with other commonly employed methods, such as Fisher's exact test and the binomial test used in the Genomic Regions Enrichment of Annotations Tool (GREAT).