14. Genome Browsers & Interactive Visual Exploration
4 Primary ToolsVisually inspecting BAM read alignments, splice junctions, variant tracks, circular chromosomal translocations, and hosting public browser Track Hubs.
⚡ Jump to Tool Tutorial:
IGV (Integrative Genomics Viewer) ↓
JBrowse 2 ↓
UCSC Genome Browser ↓
Circos ↓
| Tool | Primary Role & Purpose | Supported Platforms | Executable Pipeline |
|---|---|---|---|
| IGV (Integrative Genomics Viewer) → | Desktop and web tool for visually inspecting BAM alignments, variants, and coverage | Desktop, IGV-Web & Headless CLI | View Code ↓ |
| JBrowse 2 → | Modern, highly modular web-based and desktop genome browser supporting structural variants | Web / React / Desktop | View Code ↓ |
| UCSC Genome Browser → | Web-based exploration of public tracks, conservation, and user Track Hubs | Web Browser Portal | View Code ↓ |
| Circos → | Circular visualizations of genome-wide SVs, translocations, and copy number dynamics | Perl / Vector Graphics | View Code ↓ |
🌐 Extended Visual Exploration & Frontier AI Ecosystem:
Visualization, Statistics & AI
Genome & Alignment Browsers:
IGV (Desktop/Web), UCSC Genome Browser, JBrowse 2, Ensembl Browser, Circos, Gviz
Statistical Plotting:
ggplot2, ComplexHeatmap, pheatmap, EnhancedVolcano, seaborn, matplotlib
Interactive Apps & Notebooks:
R Shiny, Jupyter Lab, RStudio, Cirrocumulus, cellxgene
Frontier Biological AI Models:
AlphaFold 2/3, AlphaMissense, ESM-2 / ESMFold, scVI, scGPT, Geneformer, Enformer, Borzoi
🔍
Desktop & Headless Batch Alignment Exploration
Alignment Inspector
Batch Automation
Integrative Genomics Viewer (IGV) is the definitive visual browser for inspecting BAM/CRAM read alignments, base mismatches, structural breakpoints, and coverage tracks. It supports automated headless batch scripting to capture mutation snapshots.
# 1. Create headless IGV batch commands file (batch_script.txt)
cat << 'EOF' > igv_batch_script.txt
new
genome hg38
load sample_tumor.dedup.bam
load sample_normal.dedup.bam
load somatic_calls.vcf.gz
snapshotDirectory ./igv_snapshots/
goto chr7:55,248,950-55,249,150
sort base
collapse
snapshot EGFR_L858R_alignment.png
goto chr12:25,398,200-25,398,350
sort base
snapshot KRAS_G12D_alignment.png
exit
EOF
# 2. Run IGV in headless mode with virtual framebuffer
xvfb-run --auto-servernum --server-args="-screen 0 1920x1080x24" \
igv.sh -b igv_batch_script.txt
Key Flags:
xvfb-run renders high-resolution PNG snapshots on headless cloud servers; sort base sorts alignments by nucleotide at candidate mutation positions.
🌐
Modern Modular Genome Browser with SV Synteny Views
WebAssembly Browser
Synteny & Multi-Track
JBrowse 2 is a modern, extensible genome browser built on React and WebAssembly. It supports linear synteny views, circular chromosomal views, and multi-track BAM/CRAM and VCF rendering directly in web applications without server-side rendering bottlenecks.
# 1. Initialize JBrowse 2 web directory
npm install -g @jbrowse/cli
jbrowse create jbrowse2_web/
# 2. Add GRCh38 reference genome assembly
cd jbrowse2_web/
jbrowse add-assembly /ref/GRCh38.fa.gz --name hg38 --load copy
# 3. Add BAM alignment and VCF variant tracks
jbrowse add-track /data/sample.sorted.bam --load symlink --category "Alignments"
jbrowse add-track /data/variants.vcf.gz --load symlink --category "Variants"
# 4. Generate full-text search index for genes and coordinates
jbrowse text-index --attributes Name,ID,gene_id
Key Flags:
jbrowse add-assembly registers reference genomes with samtools fasta indices; jbrowse text-index builds fast client-side triage search indices.
🏛️
Web-Based Public Track Hub & Conservation Explorer
Track Hubs
Public Annotations
The UCSC Genome Browser offers interactive access to deep public genomic annotations (GENCODE, ENCODE, 100-way conservation, ClinVar). Researchers host custom datasets via Track Hubs (bigWig and bigBed) accessible through simple URL sharing.
# 1. Structure standard UCSC Track Hub directory
mkdir -p my_hub/hg38/
# 2. Define hub.txt
cat << 'EOF' > my_hub/hub.txt
hub OmicsEpigenomicsHub
shortLabel Epigenomics Hub
longLabel Multi-Omic ATAC & ChIP-Seq Peak Profiles
genomesFile genomes.txt
email admin@omics.co.in
EOF
# 3. Define genomes.txt and trackDb.txt
echo "genome hg38" > my_hub/genomes.txt
echo "trackDb hg38/trackDb.txt" >> my_hub/genomes.txt
cat << 'EOF' > my_hub/hg38/trackDb.txt
track sample_atac_coverage
bigDataUrl http://omics.co.in/data/sample.rpgc.bw
shortLabel ATAC-Seq Signal
longLabel Sample 1x Normalized ATAC-Seq Coverage
type bigWig
color 6,182,212
visibility full
autoScale on
EOF
Key Flags:
type bigWig reads binary indexed coverage streams via HTTP range requests without requiring the browser to download whole files.
⭕
Circular Genome-Wide Translocation & Ideogram Plots
Circular Ideogram
Translocation Ribbons
Circos visualizes whole-genome data in a circular format. It is particularly renowned for displaying structural variations, inter-chromosomal translocations, copy number profiles, and synteny relationships in cancer genomes.
# 1. Circos configuration file (circos.conf)
cat << 'EOF' > circos.conf
karyotype = data/karyotype/karyotype.human.txt
<ideogram>
<spacing>
default = 0.005r
</spacing>
radius = 0.90r
thickness = 40p
fill = yes
stroke_color = dgrey
stroke_thickness = 2p
show_label = yes
label_font = default
label_radius = 1.07r
label_size = 24p
</ideogram>
<links>
<link>
file = somatic_translocations.txt
radius = 0.88r
bezier_radius = 0r
color = red_a4
thickness = 3
</link>
</links>
<<include etc/colors_fonts_patterns.conf>>
<<include etc/housekeeping.conf>>
EOF
# 2. Render high-resolution circular SVG/PNG
circos -conf circos.conf -outputfile cancer_genome_circos.png
Key Flags: