Map protein–DNA interactions. Reveal chromatin state.
End-to-end Chromatin Immunoprecipitation Sequencing (ChIP-Seq) analysis for genome-wide mapping of transcription factor binding sites and histone modification patterns — from raw reads to annotated peaks and motif enrichment.
Genome-wide mapping of protein–DNA interactions
Nucleome Informatics offers end-to-end ChIP-Seq data analysis services for genome-wide mapping of transcription factor binding sites and histone modification patterns.
ChIP-Seq combines chromatin immunoprecipitation with high-throughput sequencing to identify regions of the genome bound by a protein of interest, providing insight into gene regulation and chromatin state.
Our analysis combines sequencing quality control, reference alignment, duplicate and quality filtering, peak calling suited to narrow (transcription factor) or broad (histone mark) binding profiles, peak annotation and motif enrichment analysis.
- Sequencing data quality assessment and preprocessing
- Reference genome alignment and read-level processing
- Duplicate removal and quality filtering
- Peak calling for narrow and broad profiles
- Peak annotation relative to genes and genomic features
- Motif enrichment analysis
- Differential binding analysis across conditions or replicates
- Secure delivery of raw, intermediate and final analysis files
Narrow & Broad Peak Support
Transcription factor binding produces sharp, narrow peaks. Histone modifications often span broader domains. Our pipeline selects the appropriate calling strategy for your target.
Quality-Controlled Throughout
Library complexity, cross-correlation and fraction-of-reads-in-peaks (FRiP) metrics are tracked at every stage — so you know your enrichment is real.
Built for chromatin biology
Flexible peak calling, comprehensive annotation and reproducible reporting — designed around the questions chromatin researchers actually ask.
Flexible Peak Calling
Narrow-peak calling for transcription factors and broad-peak calling for histone modifications, using established approaches.
Reference Genome Support
Analysis against GRCh38/hg38 or a client-specified reference build, as appropriate to your study.
Peak Annotation
Annotation of peaks relative to nearest genes and genomic features — promoter, exon, intron, intergenic.
Motif Enrichment
De novo and known transcription-factor motif enrichment analysis within called peaks.
Quality-Controlled Analysis
Library complexity, cross-correlation and FRiP metrics tracked throughout the workflow.
Reproducible Reporting
Structured peak sets, QC summaries and project reports delivered in a consistent format.
From first principles to frontier methods
New to chromatin biology? Start with Foundations. Already running experiments? Jump to Practitioner or Expert. Each level builds on the one before it, so you can read the page as a short course or dip in where you need to.
The big idea in plain language: ChIP-Seq tells you where on the genome a protein, or a chemical mark on histones, is sitting. That location map is the first step to understanding which genes a cell can switch on.
DNA is packaged, not naked
Each human cell fits roughly two metres of DNA into a nucleus by wrapping it around histone proteins. This DNA–protein complex is chromatin, and how it is wrapped helps decide which genes can be read.
Transcription factors are the readers
Transcription factors (TFs) recognise short DNA sequences and turn nearby genes up or down. Knowing where a TF binds shows which genes it can regulate.
Histone marks are the annotations
Chemical tags on histones, such as H3K4me3 at active promoters or H3K27me3 in Polycomb-silenced regions, label the functional state of each stretch of genome.
ChIP-Seq is a molecular snapshot
Proteins are glued to DNA, the DNA is cut into pieces, an antibody pulls out the protein you care about, and the DNA it was holding is sequenced. Think of it as a molecular highlighter for the genome.
A peak is a pile-up of reads
Sequenced fragments are mapped back to the genome. Where many fragments stack up, the protein or mark was probably present. That stack is called a peak.
The input control is your blank
Some regions look sticky or open for purely technical reasons. A matched input sample, without the antibody pull-down, shows that background so it can be separated from true signal.
For scientists planning or interpreting a project: how experiment design, depth and quality metrics translate into trustworthy peak sets.
Narrow vs broad targets
TFs give tight peaks a few hundred bp wide, while many histone marks form kilobase-scale domains, so peak callers run in different modes. ENCODE4 asks for at least 10 M usable fragments per replicate for TFs (more than 20 M recommended); broad marks need at least 20 M (more than 45 M recommended).
Replicates and controls
ENCODE4 expects two or more biological replicates, and every ChIP needs a matched input control with the same run type and read length. Replicates are what let you separate biology from noise.
The QC ladder
Q30 and adapters, then mapping rate, library complexity (NRF, PBC1, PBC2), strand cross-correlation (NSC, RSC) and FRiP. Each rung catches a different failure: poor sequencing, wrong reference, over-amplification or weak enrichment.
Peak-calling statistics
Callers model local background against input with a Poisson-type test, correct for multiple testing (FDR or q-value) and report summit position, fold enrichment and significance for each peak.
Annotation and motifs
Peaks are assigned to nearest genes and features (promoter, exon, intron, intergenic). Motif analysis then asks whether the TF's own recognition sequence is enriched near summits, a built-in sanity check on the antibody.
Differential binding
To compare conditions, replicate-aware count models work on a consensus peak set, normalise library sizes and test log2 fold changes with FDR control.
For computational biologists and reviewers: reproducibility frameworks, artefacts, quantitation and the machine-learning models now built on ChIP-seq-type data.
Reproducibility with IDR
The Irreproducible Discovery Rate ranks peaks across replicates and keeps those with consistent rank. ENCODE4 also uses pseudoreplicates: the rescue and self-consistency ratios should both stay below 2.
Artefact control
Blacklisted regions, hyper-ChIPable high-occupancy loci and antibody cross-reactivity can create convincing but false peaks. Blacklist filtering, motif checks and orthogonal controls protect your conclusions.
Absolute quantification
Standard ChIP-seq is relative. Adding spike-in chromatin from another species (ChIP-Rx or quantitative ChIP-seq) gives a reference that can reveal global gains or losses of a mark between conditions.
Base-pair resolution
ChIP-exo and ChIP-nexus trim DNA with exonuclease to expose protein–DNA footprints, and BPNet-style neural networks trained on such data describe motif syntax at single-base resolution.
Multi-omic integration
Combining several marks into chromatin states, then layering accessibility, 3D contacts and expression, turns peak lists into regulatory maps of promoters, enhancers and silenced domains.
Sequence-to-function AI
Models such as BPNet, ChromBPNet, Enformer and AlphaGenome learn from epigenomic tracks to predict how non-coding variants change regulatory activity, helping prioritise variants for follow-up.
- Peak
- A genomic region with more reads in the ChIP than expected from the input.
- Summit
- The single position of highest signal inside a peak; used to centre motif searches.
- Input / control
- Matched sample processed without antibody enrichment; models background.
- FRiP
- Fraction of Reads in Peaks, a signal-to-noise summary of the immunoprecipitation.
- Fragment length
- Size of the DNA pieces captured; estimated from the shift between forward and reverse reads.
- Pseudoreplicate
- A random half of the reads from a sample, used to test self-consistency.
- Motif
- A short, recurring DNA sequence pattern that a TF prefers to bind.
- Blacklist region
- Genomic locus known to give artefactual signal; excluded from analysis.
How a protein's address becomes a peak
ChIP-Seq turns a snapshot of where proteins sit on DNA into sequencing reads, and statistics turn those reads into binding sites.
From raw reads to annotated peaks
Each sample passes through a quality-controlled analysis workflow designed to move from raw sequencing data to annotated, high-confidence binding-site datasets.
Raw read QC
Per-base quality, adapter content, read-length distribution; trimming where needed.
Reference alignment
Reads aligned to GRCh38/hg38 or a client-specified build; primary alignment and mapping quality recorded.
Filtering
PCR duplicates, low-quality and multi-mapped reads removed; problematic regions can be masked.
Fragment modelling
Strand cross-correlation estimates fragment length and separates enrichment from background.
Peak calling
Narrow or broad mode against input control, with significance and FDR control.
Replicate concordance
Peaks compared across replicates and pseudoreplicates to retain reproducible sites.
Annotation & motifs
Nearest-gene and feature annotation, plus known and de novo motif enrichment.
Differential & report
Optional differential binding across conditions, then QC and project reports delivered securely.
Data QC & Pre-processing
Sequencing quality, read quality and adapter content assessed; quality filtering applied.
Reference Alignment
High-quality reads aligned to the selected reference genome for downstream peak analysis.
Duplicate Removal
PCR duplicates and low-quality or multi-mapped reads removed for reliable peak calling.
Peak Calling
Enriched regions identified relative to input/control — narrow or broad as appropriate.
Peak Annotation — Called peaks annotated relative to nearest genes and genomic features.
Motif Enrichment — Peak sequences analysed for known and de novo sequence motifs.
Reporting & Delivery — Peak statistics, annotation summaries and QC metrics delivered securely.
Differential Binding Analysis
Where multiple conditions or biological replicates are available, differential binding analysis can be performed on the same processed data to identify condition-specific or treatment-responsive binding regions.
Reading the diagnostic plots like a reviewer
Good ChIP-seq papers show their quality control. These are the plots reviewers look for, with the community reference values from the ENCODE consortium so you can benchmark any dataset.
reads in peaks ÷ total usable readsSignal-to-noise of the pull-down; compare between similar targets and antibodies.
distinct mapped positions ÷ total mapped readsFraction of non-redundant reads; low values mean over-amplification.
n₁ ÷ n≥1 · n₁ ÷ n₂n₁, n₂ = positions with exactly one or two reads; n≥1 = positions with at least one.
NSC = CCmax ÷ CCmin · RSC = (CCfrag − CCmin) ÷ (CCphantom − CCmin)Normalised and relative strand cross-correlation from Figure 4.
p = P(X ≥ k | λlocal), λlocal = max(λbg, λ1k, λ5k, λ10k)Poisson test against a locally estimated background, as used by MACS-family callers; q-values apply Benjamini–Hochberg correction.
rescue = max(Np,Nt) ÷ min(Np,Nt) · self = max(N1,N2) ÷ min(N1,N2)Peak counts from true replicates (Nt), pooled pseudoreplicates (Np) and self-consistency pairs (N1, N2).
What the peaks actually look like
Aggregate profiles, signal heatmaps and reproducibility plots are the standard way to show that peaks are real, well-centred and consistent across replicates.
The remainder are distributed across exons, introns and intergenic space, typical of distal regulatory elements.
Compare conditions, integrate marks
Differential binding shows what changes between conditions. Combining several histone marks reveals the chromatin state of each region: active promoter, enhancer, transcribed gene or Polycomb-silenced domain.
Structured outputs, ready for biology
At project completion, clients receive a structured set of sequencing, analysis and reporting outputs via secure shared storage.
Raw & Processed Data
FASTQ files — raw and appropriately processed sequence data.
QC Reports
Sample-level QC including library complexity and enrichment metrics.
Alignment Files
Processed BAM files with associated index files.
Peak Calls
Narrow- or broad-peak files (BED/narrowPeak) per sample and condition.
Annotated Peaks
Peak sets annotated with nearest genes and genomic features.
Motif Results
Known and de novo motif enrichment outputs within called peaks.
Summary Report
Sample-wise QC, alignment, peak-calling and annotation statistics.
Secure Delivery
Project files via secure shared storage or cloud-based access.
What we accept
Flexible input options for sequencing-plus-analysis or analysis-only projects.
ChIP DNA & Controls
We accept chromatin immunoprecipitated DNA (ChIP DNA) and matched input/control DNA, as well as pre-generated sequencing data where analysis-only services are required.
Project-specific requirements for DNA quantity, concentration, library preparation, sequencing depth and read configuration are finalised according to the target protein, study design and sequencing strategy.
Contact us for a project-specific sample submission checklist and recommended sequencing depth.
ChIP DNA + matched input/control
or pre-generated FASTQ
Proven on real chromatin datasets
Production metrics from transcription-factor and histone-modification ChIP-Seq projects.
Transcription Factor Binding-Site Mapping
Narrow-peak calling · Matched input control
| Mean raw-data Q30 | 92.1% |
| Mean primary alignment rate | 98.6% |
| Mean FRiP score | 0.09 |
| Peaks called (high-confidence) | ~18,400 |
| Peaks annotated to promoters | ~34% |
The dataset achieved high sequencing quality and alignment rates, with high-confidence peak sets and annotated outputs delivered alongside a project summary report.
Histone Modification Profiling
Broad-peak calling · Replicate cohorts
| Peak mode | Broad domain |
| Enrichment metrics | Consistent |
| Replicate reproducibility | High |
| Differential binding | Supported |
| Domain calls | Reproducible |
In production histone ChIP-Seq datasets, we have observed consistent enrichment metrics and reproducible broad-domain peak calls across biological replicates, supporting robust differential binding analysis where required.
Where chromatin profiling is heading
ChIP-seq remains the reference method, but a new generation of in-situ assays and sequence-based AI models is changing how regulatory genomes are mapped and interpreted. Here is how they relate.
Sensitivity for H3K4me3 peaks in mouse haploid round spermatids
| Assay | Principle | Strengths | Watch-outs |
|---|---|---|---|
| ChIP-seq | Crosslinked chromatin immunoprecipitation | Reference standard with community QC rules and public data | Needs more cells; higher background; antibody-dependent |
| CUT&RUN | Antibody-guided nuclease cleaves DNA in situ | Low background; small inputs | Can be weaker for some TFs; accessibility bias |
| CUT&Tag | Antibody-guided Tn5 tagmentation in situ | High signal-to-noise; very low input; single-cell formats | Bias to open chromatin; recovers a subset of ChIP-seq peaks |
| ChIP-exo / nexus | Exonuclease trimming to the crosslink boundary | Near-base-pair footprints | More complex protocol and library requirements |
CUT&RUN and CUT&Tag
Antibody-guided nuclease or transposase acts inside intact nuclei, which lowers background and allows profiling from small samples, including single cells. Peaks should be interpreted with the assay's accessibility bias in mind.
Multimodal single-cell chromatin
Single-cell CUT&Tag and nanobody-based variants profile histone marks cell by cell, and some formats read several chromatin features in the same cells, resolving regulatory heterogeneity within tissues.
Spike-in normalisation
A fixed amount of foreign chromatin and a species-specific antibody target let reads be scaled to an internal reference, so global increases or decreases in a histone mark become measurable.
Service highlights
End-to-end support for research and translational chromatin-biology projects.
End-to-End Analysis
From raw sequencing data through QC, alignment, peak calling, annotation and reporting.
Narrow & Broad Peaks
Analysis suited to both transcription-factor and histone-modification binding profiles.
Comprehensive Annotation
Peak annotation relative to genes and genomic features, with motif enrichment analysis.
Transparent QC
Library complexity, enrichment and FRiP metrics incorporated into project reporting.
Flexible Study Design
Support for individual samples, replicate cohorts and differential binding projects.
Secure Data Delivery
Raw, intermediate and final datasets delivered through secure project storage.
Frequently asked, in plain language
basicWhat is ChIP-Seq in one sentence?
basicDo I need to do the sequencing as well?
basicWhy is an input control needed?
intermediateHow much sequencing depth should I plan?
intermediateMy FRiP is low. Has the experiment failed?
intermediateNarrow-peak or broad-peak calling: which should I use?
advancedShould I use CUT&Tag or CUT&RUN instead of ChIP-seq?
advancedHow are differential binding results kept reliable?
advancedCan ChIP-seq data feed machine-learning models?
Key literature & standards
Selected sources that underpin the reference values and methods on this page. Figures labelled "simulated" are illustrations generated for this page, not client data.
- Landt SG, et al. ChIP-seq guidelines and practices of the ENCODE and modENCODE consortia. Genome Research 2012;22:1813–1831. Link
- ENCODE Project. ENCODE4 transcription factor ChIP-seq data standards and processing pipeline. encodeproject.org
- ENCODE Project. ENCODE4 histone ChIP-seq data standards and processing pipeline. encodeproject.org
- Zhang Y, et al. Model-based analysis of ChIP-Seq (MACS). Genome Biology 2008;9:R137.
- Li Q, Brown JB, Huang H, Bickel PJ. Measuring reproducibility of high-throughput experiments. Annals of Applied Statistics 2011;5:1752–1779.
- Amemiya HM, Kundaje A, Boyle AP. The ENCODE Blacklist: identification of problematic regions of the genome. Scientific Reports 2019;9:9354.
- Ross-Innes CS, et al. Differential oestrogen receptor binding is associated with clinical outcome in breast cancer. Nature 2012;481:389–393 (DiffBind).
- Orlando DA, et al. Quantitative ChIP-Seq normalization reveals global modulation of the epigenome. Cell Reports 2014;9:1163–1170.
- Heinz S, et al. Simple combinations of lineage-determining transcription factors prime cis-regulatory elements required for macrophage and B cell identities. Molecular Cell 2010;38:576–589 (HOMER).
- Ernst J, Kellis M. ChromHMM: automating chromatin-state discovery and characterization. Nature Methods 2012;9:215–216.
- Rhee HS, Pugh BF. Comprehensive genome-wide protein-DNA interactions detected at single-nucleotide resolution. Cell 2011;147:1408–1419 (ChIP-exo).
- He Q, Johnston J, Zeitlinger J. ChIP-nexus enables improved detection of in vivo transcription factor binding footprints. Nature Biotechnology 2015;33:395–401.
- Skene PJ, Henikoff S. An efficient targeted nuclease strategy for high-resolution mapping of DNA binding sites. eLife 2017;6:e21856 (CUT&RUN).
- Kaya-Okur HS, et al. CUT&Tag for efficient epigenomic profiling of small samples and single cells. Nature Communications 2019;10:1930.
- Abbasova L, et al. CUT&Tag recovers up to half of ENCODE ChIP-seq histone acetylation peaks. Nature Communications 2025;16. Link
- Wang R, et al. Benchmark of chromatin–protein interaction methods in haploid round spermatids. Frontiers in Cell and Developmental Biology 2025. Link
- Avsec Ž, et al. Base-resolution models of transcription-factor binding reveal soft motif syntax. Nature Genetics 2021;53:354–366. PubMed
- Avsec Ž, et al. Effective gene expression prediction from sequence by integrating long-range interactions (Enformer). Nature Methods 2021;18:1196–1203.
- ChromBPNet: bias factorized, base-resolution deep learning models of chromatin accessibility reveal cis-regulatory sequence syntax, transcription factor footprints and regulatory variants. bioRxiv 2024. Link
- Advancing regulatory variant effect prediction with AlphaGenome. 2026. PubMed









