Version Compatibility

Reference examples tested with: minimap2 2.26+, samtools 1.19+

Before using code patterns, verify installed versions match. If versions differ:

• CLI: <tool> --version then <tool> --help to confirm flags

If code throws ImportError, AttributeError, or TypeError, introspect the installed package and adapt the example to match the actual API rather than retrying.

Long-Read Alignment with minimap2

"Align my long reads to the reference" → Map ONT or PacBio reads using minimap2 with technology-specific presets for optimal sensitivity and accuracy.

• CLI: minimap2 -ax map-ont ref.fa reads.fq | samtools sort -o aligned.bam (ONT), minimap2 -ax map-hifi (PacBio HiFi)

Oxford Nanopore Alignment

# Basic ONT alignment
minimap2 -ax map-ont reference.fa reads.fastq.gz | \
    samtools sort -o aligned.bam
samtools index aligned.bam

PacBio HiFi Alignment

# PacBio HiFi reads (high accuracy)
minimap2 -ax map-hifi reference.fa reads.fastq.gz | \
    samtools sort -o aligned.bam
samtools index aligned.bam

PacBio CLR Alignment

# PacBio CLR (continuous long reads, lower accuracy)
minimap2 -ax map-pb reference.fa reads.fastq.gz | \
    samtools sort -o aligned.bam
samtools index aligned.bam

Pre-Build Index for Multiple Runs

# Build index once
minimap2 -d reference.mmi reference.fa

# Use index for alignment
minimap2 -ax map-ont reference.mmi reads.fastq.gz | samtools sort -o aligned.bam

Common Options

minimap2 -ax map-ont \
    -t 8 \                         # Threads
    -R '@RG\tID:sample\tSM:sample' \  # Read group
    --secondary=no \               # No secondary alignments
    --MD \                         # Generate MD tag for variants
    -Y \                           # Use soft clipping for supplementary
    reference.fa reads.fastq.gz | \
    samtools sort -@ 4 -o aligned.bam