roh-viz

Perl HTML report generator for ROH review. It parses RG segments from bcftools roh output, queries alt-genotype calls from the supplied VCF/BCF with bcftools query, then renders an HTML/JavaScript report with optional embedded D3/Pako assets.

Quick Start

• Command: roh-viz -i roh.txt -v cohort.bcf -o output.html
• Local executable: /home/vimalinx/miniforge3/envs/bio/bin/roh-viz
• Required companions: bcftools, bash, zless

When To Use This Tool

• Reviewing runs of homozygosity from bcftools roh in a browser instead of raw text
• Combining ROH segments with homozygosity-rate traces derived from the source VCF/BCF
• Filtering the visualization by samples, regions, or minimum ROH length
• Generating a self-contained offline HTML report with embedded JavaScript assets

Common Patterns

# Basic ROH visualization
bcftools roh --AF-dflt 0.5 -G 30 -Or -o roh.txt cohort.bcf
roh-viz -i roh.txt -v cohort.bcf -o roh.html

# Embed JavaScript for offline viewing
roh-viz -i roh.txt -v cohort.bcf -e 1 -o roh_offline.html

# Restrict to selected samples and regions
roh-viz -i roh.txt -v cohort.bcf -s sample1,sample2 -r chr1,chr2 -l 500000 -o subset.html

Recommended Workflow

1. Generate bcftools roh output first, then keep the original VCF/BCF available for genotype-rate calculation.
2. Feed the ROH text through -i and the variant file through -v.
3. Tune -l, -s, and -r to reduce clutter before sharing the report.
4. Use -e 1 whenever the final HTML must work without internet access.

Guardrails

• The real ROH-input flag is -i, not -r. Source inspection shows -r means genomic regions, but the built-in error message and example text incorrectly say Missing the -r option / roh-viz -r roh.txt ....
• Both -i and -v are required by the parser.
• The script shells out to bcftools query and zless, so those tools must be available on PATH.
• Only RG lines from the ROH file are plotted as ROH segments; other record types are ignored.
• If -o is omitted, the script writes HTML to stdout.
• By default it links D3/Pako from remote URLs; use -e 1 to embed those assets for offline viewing.