💡 Quick Summary
Random DNA Sequence generates a random nucleotide sequence of the length you specify. Each base (G, A, C, T) is chosen with equal probability. Random sequences are useful as null models for evaluating the significance of sequence analysis results.
📋 How to Use
- Enter the desired length in bases (default: 1000; maximum: 10,000,000).
- Choose how many sequences to generate (1, 10, 50, or 100).
- Click Run. Each sequence is output as a FASTA record with an auto-generated title. Use Copy to copy the plain-text result.
🔬 Applications
- Generating null-model sequences for evaluating the significance of motif or pattern search results
- Creating random backgrounds for benchmarking alignment or annotation tools
- Producing synthetic sequences with equal base composition for statistical testing
- Testing sequence analysis pipelines with known-random inputs
⚠️ Common Mistakes & Warnings
Sequences are randomly generated each run
Every click of Run produces a different random sequence. Each base position is chosen independently and uniformly at random.
Large lengths or many sequences may be slow
Generating 100 sequences of 10,000,000 bases each creates 1,000,000,000 characters in the browser. For very large outputs, use a smaller count or length.
❓ Frequently Asked Questions
Are the base frequencies equal?
Yes — each of the four bases (G, A, C, T) is chosen with equal probability (25% each). The output does not reflect any organism's actual base composition.
Why does the output have 60-character lines?
Sequences are wrapped at 60 characters per line, which is the standard FASTA format for nucleotide sequences.
Can I generate sequences longer than 10,000,000 bases?
Not with this tool — the limit is set to avoid excessive browser memory use. For longer sequences, consider a command-line tool.
