bio-chipseq-spike-in-normalization

bio-chipseq-spike-in-normalization is a skill for Claude Code, Codex from PKU-YuanGroup/OpenAI4S. It costs 175 tokens per session (4,747 once invoked), scanned A, a copy of bio-chipseq-spike-in-normalization, MIT.

A guide to spike-in normalization, a method that adds a known reference material to sequencing samples so signal levels can be compared across conditions.

In plain words
What is it for?
Calculating spike-in scaling factors and applying them to ChIP-seq, CUT&RUN, or CUT&Tag analyses and downstream statistical tools.
Why use it?
It helps detect real global changes in DNA-associated signal that ordinary read-count normalization might hide.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Calculating spike-in scaling factors and applying them to ChIP-seq, CUT&RUN, or CUT&Tag analyses and downstream statistical tools.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add PKU-YuanGroup/OpenAI4S --skill bio-chip-seq-spike-in-normalization
Clone the repo
git clone --depth 1 https://github.com/PKU-YuanGroup/OpenAI4S

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for bio-chipseq-spike-in-normalization

README.md
[![agentmods](https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization/github.svg)](https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization)
Your own site
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for bio-chipseq-spike-in-normalization

Your own site · 80×15
<a href="https://agentmods.dev/skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization"><img src="https://agentmods.dev/badge/skills/pku-yuangroup/openai4s/bio-chip-seq-spike-in-normalization.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 175 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,747 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 97% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00175 $0.04747
Opus 5 $0.00088 $0.02374
Sonnet 5 $0.00035 $0.00949
Haiku 4.5 $0.00017 $0.00475

Measured 8d ago against content hash 985abd0572e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

bio-chipseq-spike-in-normalization scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

97% identical to bio-chipseq-spike-in-normalization — 12 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/bioskills/bio-chip-seq-spike-in-normalization/SKILL.md · 357 lines

How it starts

The opening of the file, as written. The whole thing — 357 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Version Compatibility

Reference examples tested with: DiffBind 3.20+, DESeq2 1.42+, edgeR 4.0+, csaw 1.36+, ChIPseqSpikeInFree 1.6+, SpikChIP 1.0+, SpikeFlow (NAR Genom Bioinform 2024), samtools 1.19+, bowtie2 2.5+.

ChIP-seq Spike-In Normalization

"Account for global signal changes that defeat standard normalization" -> Add exogenous reference chromatin (Drosophila for human/mouse ChIP-Rx; E. coli carryover for CUT&RUN/CUT&Tag) at fixed concentration BEFORE IP, derive scaling factors from spike-in read counts, and apply at the read or size-factor level (never to peak counts) to enable quantitative cross-condition comparison.

  • CLI: align reads to combined target + spike genome; count spike reads via samtools view -c
  • R (DiffBind integration): dba.normalize(obj, spikein = TRUE)
  • R (DESeq2 / edgeR): sizeFactors(dds) <- 1 / scale_factors (note inverse)
  • CLI (deepTools tracks): bamCoverage --scaleFactor <derived> (use alone; --normalizeUsing compounds with it)
  • Wrapper: SpikeFlow (Snakemake; 2024) automates end-to-end
  • Post-hoc detection: ChIPseqSpikeInFree (when no spike-in was added)

The fundamental rule: spike-in scaling is applied at the READ level (via size factors or --scaleFactor), never multiplied into peak counts. This is a common implementation error in published spike-in ChIP.

When Spike-In Is Required

Experimental design Spike-in needed?
HDAC inhibitor -> global H3K27ac increase Yes
BET inhibitor (JQ1, OTX015) -> global BRD4 / H3K27ac decrease Yes
EZH2 inhibitor -> global H3K27me3 loss Yes
DNMT inhibitor -> global 5mC loss; downstream histone mark shifts Yes
Target factor knockdown / degron Yes (or matched-input subtraction)
Cell-cycle synchronization / arrest Yes
Dosage titration Yes
Standard TF perturbation, local rebinding expected No (reads-in-peaks RLE works)
Histone mark cross-cell-type comparison Recommended
CUT&RUN/CUT&Tag standard E. coli carryover (automatic); deliberate Drosophila for high-stakes
Replicate-only experiment, no condition comparison No

Read the full file on GitHub · 357 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 357 lines · 175 tokens per session scan A 985abd0572e1

Subscribe to this mod's changes

bio-chipseq-spike-in-normalization is a skill published in the GitHub repository PKU-YuanGroup/OpenAI4S (403 stars, last pushed yesterday), licensed MIT. It adds 175 tokens to every session and 4,747 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. It is 97% identical to bio-chipseq-spike-in-normalization, differing in 12 lines, and is treated as a copy.

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