Agent skill
bio-crispr-screens-jacks-analysis
JACKS (Joint Analysis of CRISPR/Cas9 Knockout Screens) for modeling sgRNA efficacy and gene essentiality. Use when analyzing multiple CRISPR screens simultaneously or when accounting for variable sgRNA efficiency across experiments.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/jacks-analysis
SKILL.md
JACKS CRISPR Screen Analysis
JACKS jointly models sgRNA efficacy and gene essentiality across multiple experiments. It infers both gene-level fitness effects and sgRNA-specific efficiency.
Installation
pip install jacks
# or
git clone https://github.com/felicityallen/JACKS.git
cd JACKS && pip install -e .
Input File Formats
Count Data
# counts.txt (tab-separated)
sgRNA Gene Sample1 Sample2 Sample3 Control1 Control2
sgRNA1 GENE_A 100 120 90 80 85
sgRNA2 GENE_A 200 180 210 150 160
sgRNA3 GENE_B 50 45 55 60 58
...
Replicate Map
# replicatemap.txt
Sample1 Experiment1 Day14
Sample2 Experiment1 Day14
Sample3 Experiment2 Day14
Control1 Experiment1 Day0
Control2 Experiment2 Day0
Guide-Gene Map
# guidemap.txt
sgRNA1 GENE_A
sgRNA2 GENE_A
sgRNA3 GENE_B
sgRNA4 GENE_B
...
Basic JACKS Analysis
Command Line
# Run JACKS
python -m jacks.run_JACKS \
counts.txt \
replicatemap.txt \
guidemap.txt \
output_prefix \
--ctrl_sample_pattern "Day0" \
--ctrl_sample_pattern_column "Condition"
Python API
from jacks import infer
import pandas as pd
# Load data
counts = pd.read_csv('counts.txt', sep='\t', index_col=0)
guide_gene_map = pd.read_csv('guidemap.txt', sep='\t', header=None, names=['sgRNA', 'Gene'])
replicate_map = pd.read_csv('replicatemap.txt', sep='\t', header=None,
names=['Sample', 'Experiment', 'Condition'])
# Separate control and treatment samples
ctrl_samples = replicate_map[replicate_map['Condition'] == 'Day0']['Sample'].tolist()
treatment_samples = replicate_map[replicate_map['Condition'] == 'Day14']['Sample'].tolist()
# Run JACKS inference
# n_iterations=10000: MCMC iterations. Increase for final analysis.
# burn_in=1000: Burn-in period. Should be ~10% of iterations.
jacks_results = infer.run_inference(
counts,
guide_gene_map,
treatment_samples,
ctrl_samples,
n_iterations=10000,
burn_in=1000
)
Output Files
| File | Description |
|---|---|
_gene_JACKS_results.txt |
Gene-level essentiality scores |
_grna_JACKS_results.txt |
sgRNA-level efficacy estimates |
_jacks_full_data.pickle |
Full model for downstream analysis |
Interpret Gene Results
import pandas as pd
import numpy as np
# Load gene results
genes = pd.read_csv('output_gene_JACKS_results.txt', sep='\t')
# JACKS score: negative = essential (dropout), positive = enriched
# Columns: gene, X1 (effect), X2 (std), fdr_log10
# Essential genes (significant negative effect)
# fdr_threshold=-1: log10(FDR) < -1 means FDR < 0.1
essential = genes[(genes['X1'] < 0) & (genes['fdr_log10'] < -1)]
essential = essential.sort_values('X1')
print(f'Essential genes: {len(essential)}')
print(essential.head(20))
# Enriched genes
enriched = genes[(genes['X1'] > 0) & (genes['fdr_log10'] < -1)]
enriched = enriched.sort_values('X1', ascending=False)
print(f'Enriched genes: {len(enriched)}')
sgRNA Efficacy Analysis
import pandas as pd
# Load sgRNA results
guides = pd.read_csv('output_grna_JACKS_results.txt', sep='\t')
# Efficacy scores range from 0 (ineffective) to 1 (highly effective)
# X1 column contains efficacy estimates
# Identify poor sgRNAs
# efficacy<0.3: sgRNAs with low efficacy. Consider removal in future libraries.
poor_guides = guides[guides['X1'] < 0.3]
print(f'Low efficacy guides: {len(poor_guides)}')
# Group by gene to assess library quality
gene_efficacy = guides.groupby('Gene')['X1'].agg(['mean', 'std', 'count'])
gene_efficacy = gene_efficacy.sort_values('mean')
print(gene_efficacy.head(20))
Visualization
Gene Effect Plot
import matplotlib.pyplot as plt
import numpy as np
genes = pd.read_csv('output_gene_JACKS_results.txt', sep='\t')
fig, ax = plt.subplots(figsize=(10, 8))
# Color by significance
colors = ['red' if fdr < -1 else 'gray' for fdr in genes['fdr_log10']]
ax.scatter(genes['X1'], -genes['fdr_log10'], c=colors, alpha=0.5, s=10)
ax.axhline(1, linestyle='--', color='black', alpha=0.5) # FDR = 0.1
ax.axvline(0, linestyle='-', color='gray', alpha=0.3)
ax.set_xlabel('JACKS Score (negative = essential)')
ax.set_ylabel('-log10(FDR)')
ax.set_title('JACKS Gene Essentiality')
# Label top hits
top = genes[genes['fdr_log10'] < -2].nsmallest(10, 'X1')
for _, row in top.iterrows():
ax.annotate(row['gene'], (row['X1'], -row['fdr_log10']))
plt.savefig('jacks_volcano.png', dpi=150)
sgRNA Efficacy Distribution
import matplotlib.pyplot as plt
guides = pd.read_csv('output_grna_JACKS_results.txt', sep='\t')
plt.figure(figsize=(8, 5))
plt.hist(guides['X1'], bins=50, edgecolor='black')
plt.axvline(0.5, color='red', linestyle='--', label='Efficacy = 0.5')
plt.xlabel('sgRNA Efficacy')
plt.ylabel('Count')
plt.title('sgRNA Efficacy Distribution')
plt.legend()
plt.savefig('sgrna_efficacy.png', dpi=150)
Multi-Screen Analysis
JACKS strength is joint analysis across experiments.
# Define multiple experiments in replicate map
# replicatemap.txt:
# Sample Experiment Condition
# Screen1_T1 Screen1 Treatment
# Screen1_T2 Screen1 Treatment
# Screen1_C1 Screen1 Control
# Screen2_T1 Screen2 Treatment
# Screen2_T2 Screen2 Treatment
# Screen2_C1 Screen2 Control
# JACKS will learn shared sgRNA efficacy across screens
# while estimating screen-specific gene effects
Comparing JACKS vs MAGeCK
| Feature | JACKS | MAGeCK |
|---|---|---|
| sgRNA efficacy modeling | Yes | No |
| Multi-experiment joint analysis | Yes | Limited |
| Statistical framework | Bayesian | MLE/RRA |
| Speed | Slower | Faster |
| Best for | Multiple screens | Single screen |
Advanced Options
from jacks import infer
# Run with custom parameters
results = infer.run_inference(
counts,
guide_gene_map,
treatment_samples,
ctrl_samples,
n_iterations=50000, # 50000: Publication quality. 10000 for exploration.
burn_in=5000, # 5000: 10% of iterations.
apply_w_hp=True, # Hierarchical prior on efficacy
fixed_w=False, # Learn sgRNA efficacy (set True to fix at 1)
w_alpha=0.5, # Prior shape for efficacy
w_beta=0.5 # Prior rate for efficacy
)
Integration with Other Tools
Compare with MAGeCK
import pandas as pd
jacks = pd.read_csv('jacks_gene_results.txt', sep='\t')
mageck = pd.read_csv('mageck.gene_summary.txt', sep='\t')
# Merge results
merged = pd.merge(jacks, mageck, left_on='gene', right_on='id')
# Compare rankings
from scipy.stats import spearmanr
corr, pval = spearmanr(merged['X1'], merged['neg|score'])
print(f'Spearman correlation: {corr:.3f} (p={pval:.2e})')
Use sgRNA Efficacy for Library Design
# Extract high-efficacy guides for future libraries
guides = pd.read_csv('output_grna_JACKS_results.txt', sep='\t')
# efficacy>0.7: High efficacy sgRNAs for optimized libraries.
good_guides = guides[guides['X1'] > 0.7][['sgRNA', 'Gene', 'X1']]
good_guides.to_csv('high_efficacy_guides.csv', index=False)
Related Skills
- mageck-analysis - Alternative screen analysis method
- hit-calling - Statistical hit identification
- screen-qc - Quality control before analysis
- batch-correction - Handle batch effects in multi-screen data
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
Didn't find tool you were looking for?