PeakSeq

PeakSeq identifies and ranks enriched genomic regions (peaks) from Chromatin Immunoprecipitation followed by sequencing (ChIP-seq) data to detect transcription factor binding sites and chromatin modifications.

Key Features:

• Two-Pass Strategy: Employs a two-pass analytical approach to differentiate genuine binding sites from background noise caused by open chromatin and mappability biases.
• Control Integration: Incorporates input-DNA controls for normalization to distinguish true enrichment from regions of naturally open chromatin.
• Scoring Approach: Computes enrichments and significances by comparing ChIP-seq signals against normalized control datasets to rank peak regions.
• Experimental Design Optimization: Estimates required sequencing depth for desired coverage and assesses the marginal information gain from increasing replicates beyond two.

Scientific Applications:

• Transcription Factor Binding Site Mapping: Identification and ranking of genome-wide transcription factor binding sites from ChIP-seq experiments.
• Chromatin Modification Profiling: Detection and characterization of genome-wide chromatin modifications using ChIP-seq data.

Methodology:

Performs a two-pass analysis to separate true signal from background related to open chromatin and mappability; integrates input-DNA controls for normalization; applies a scoring method that compares ChIP-seq data to normalized control datasets to calculate enrichments and significances; estimates sequencing depth requirements and evaluates replicate number effects (noting marginal gains beyond two replicates).