# Archaic Introgression

Detect Neanderthal and Denisovan introgression segments from modern human genomes

- Repository: https://github.com/ClawBio/ClawBio (1172 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add ClawBio/ClawBio --skill archaic-introgression -g -a claude-code -y`
Codex: `npx skills add ClawBio/ClawBio --skill archaic-introgression -g -a codex -y`
Cursor: `npx skills add ClawBio/ClawBio --skill archaic-introgression -g -a cursor -y`
Gemini CLI: `npx skills add ClawBio/ClawBio --skill archaic-introgression -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add ClawBio/ClawBio`

## Description

Detect Neanderthal and Denisovan introgression segments from modern human genomes

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Archaic Introgression Detector

## Trigger

**Fire when:**
- User asks about Neanderthal or Denisovan DNA in modern humans
- User wants to detect archaic introgression segments
- User mentions IBDmix, Sprime, or hmmix methods
- User has modern + archaic VCF files and wants to compare them

**Do NOT fire when:**
- User asks about general ancestry or population structure (use claw-ancestry-pca)
- User asks about pharmacogenomics or clinical variants
- User wants admixture proportions without segment-level detail

## Why This Exists

Between 1-4% of non-African modern human genomes derive from archaic hominins
(Neanderthals, Denisovans). Identifying these segments matters for understanding
human evolution, disease susceptibility, and immune adaptation. Three complementary
methods exist (IBDmix, Sprime, hmmix), each with different strengths. This skill
wraps all three behind a unified interface with a pure-Python fallback when
external binaries are unavailable.

## Core Capabilities

1. **IBDmix**: Detect segments shared IBD between modern and archaic genomes using LOD score thresholds
2. **Sprime**: Identify introgressed haplotypes without requiring an archaic reference panel
3. **hmmix**: HMM-based detection of archaic ancestry tracts
4. **Pure-Python fallback**: LOD-score-based segment calling when IBDmix binary is not installed
5. **EIGENSTRAT support**: Read .ind/.snp/.geno files (text and binary packed formats)
6. **Summary statistics**: Per-individual introgression burden, segment count, mean length

## Scope

One skill, one task: detect and report archaic introgression segments. Does not
perform downstream functional annotation of introgressed variants (chain with
vcf-annotator for that).

## Input Formats

- **Modern genotypes**: VCF (uncompressed or .vcf.gz with .tbi index)
- **Archaic genotypes**: VCF (Neanderthal/Denisovan reference panel)
- **EIGENSTRAT**: .ind + .snp + .geno files (text or binary packed format)

## Workflow

The rest: https://github.com/ClawBio/ClawBio/blob/HEAD/skills/archaic-introgression/SKILL.md