MotifQu

MotifQu is a quantum motif search and discovery tool using Grover's algorithm. It provides two main functions:

1. Motif Search: Find occurrences of a known motif pattern in a genome
2. Motif Discovery: Discover all significant motifs (k-mers) in a genome using quantum amplitude amplification

Install

pip install MotifQu

Usage

Discover Motifs (New!)

Find all significant k-mers in a genome:

# Discover 6-mers appearing at least 3 times
motifqu discover --fasta genome.fa -k 6 --min-count 3

# Discover 8-mers, show top 20 results
motifqu discover --fasta genome.fa -k 8 --min-count 2 --topk 20

# Ignore reverse complement
motifqu discover --fasta genome.fa -k 6 --min-count 3 --no-revcomp

Search for Specific Motif

# Exact match
motifqu search --fasta genome.fa --motif GTTGTTGGAGAAG --mismatches 0

# Allow 1 mismatch
motifqu search --fasta genome.fa --motif TATAAA --mismatches 1

List Known Biological Motifs

motifqu list-motifs

Expand IUPAC Pattern

# Expand E-box pattern (CANNTG)
motifqu expand CANNTG

Coordinate Output

MotifQu prints both:

• 1-based inclusive coordinates: contig:start-end
• 0-based half-open interval: [start,end)

These coordinates are relative to the FASTA sequence provided.

Biological Context

The quantum motif discovery tool is designed for:

• Transcription Factor Binding Sites (TFBS) - identifying regulatory sequences
• Repeat elements - finding tandem repeats and microsatellites
• Conserved sequences - detecting evolutionarily preserved patterns

The algorithm uses Grover's search to amplify the probability of significant k-mers (those appearing >= threshold times), providing a quadratic speedup over classical enumeration for the 4^k k-mer search space.

Notes

• For discovery, k-mer lengths 4-10bp are recommended (4^k states require 2k qubits)
• The oracle is built from classical pre-computation of k-mer counts
• Reverse complement is counted as the same motif by default (biological DNA is double-stranded)