barcodesDB • Search barcodes

Search barcodes

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Search options

Changing these fetches a fresh set of results (page resets).

Output length k=18

Output length (k)

Substring max length equals output k.

Notes

Sequence contains (optional)

If empty, all barcodes match (subject to GC filter).

Reverse complement

GC% min

GC% max

Page size

Optional sequence filters Off

Optional sequence-level filters can flag or exclude barcodes containing simple short motifs. These filters do not guarantee functional neutrality and are not organism-specific.

Motif mode

Filter homopolymers runs > N

Max run length:

Detects consecutive runs of the same base (A, C, G, or T) longer than the threshold. e.g., AAAAA (5 A's) fails with max=4.

Filter low-complexity sequences entropy

Min Shannon entropy:

Shannon entropy H = -sum(p_i·log₂(p_i)) over A/C/G/T. Max = 2.0 (perfectly balanced). Threshold: sequences with H below this are flagged.

Filter common restriction sites 50 sites

All sites below are checked when this filter is enabled. Both forward and reverse-complement strands are scanned.

Flag short functional-like motifs 25 motifs

These are conservative sequence patterns, NOT organism-specific annotations. All motifs below are checked when enabled.

Filter dinucleotide repeats ≥6 bp

Detects ≥3 consecutive dinucleotide repeats (≥6 bp). e.g., ATATAT, CACACAC. Excludes homopolymer runs.

Filter trinucleotide repeats ≥9 bp

Detects ≥3 consecutive trinucleotide repeats (≥9 bp). e.g., CAGCAGCAG, ATCATCATC.

Filter tetranucleotide repeats ≥12 bp

Detects ≥3 consecutive tetranucleotide repeats (≥12 bp). e.g., GATAGATAGATA.

Filter custom sequence motif