About - dsRNA Primer Design Tool

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About This Tool

The dsRNA Primer Design Tool is a free, web-based platform for designing double-stranded RNA (dsRNA) primers for RNA interference (RNAi)-based pest control research. It was developed to assist researchers in identifying optimal dsRNA target regions within insect pest genes, with integrated off-target safety assessment against non-target species.

The tool was originally developed for Spodoptera frugiperda (Fall armyworm) for gene targeting but is applicable to any insect species.

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Dr. Surjeet Kumar Arya Developer Department of Entomology University of Kentucky Lexington, KY, USA

How to Acknowledge

This tool is currently under development and has not yet been formally published. If you use it in your research, we kindly ask that you acknowledge it as:

dsRNA Primer Design Tool (https://dsrna.nonmodelinsectseq.com), developed by Dr. Surjeet Kumar Arya, University of Kentucky, USA. A manuscript describing this tool is in preparation.

How to Use

Upload or paste your target gene sequence

Upload a FASTA file (.fasta, .fa, .fas, .txt) or paste your sequence directly. The sequence should be at least 500 bp for best results.

Set analysis parameters

Target Length: Size of dsRNA region (315-500 bp). Default 450 bp is optimal.
Max Mismatches: Mismatches allowed in off-target alignment. Default 2 recommended.
Top Candidates: Number of ranked primers to return (5-20).

Select target region (optional)

Choose Auto (full sequence), CDS, 5 UTR, or 3 UTR. CDS is recommended for maximum knockdown efficiency. Provide coordinates from your NCBI GenBank record if known.

Select off-target species

Choose non-target species to check. Currently available: Apis mellifera (Honey bee), Bombus terrestris (Bumblebee), and Homo sapiens (Human). Selecting all is recommended.

Interpret results

Results are ranked by Final Score. Focus on PASS candidates with Final Score greater than 70, GC content 40-60%, and low MFE penalty. Download the full results ZIP for complete files.

Use primers for dsRNA synthesis

Add T7 promoter sequence (TAATACGACTCACTATA) to both forward and reverse primers for in vitro transcription. Anneal the two RNA strands to form the dsRNA duplex.

Scoring System

Quality Score (0-100)

Criterion	Penalty	Rationale
GC content < 30% or > 70%	-20 pts	Poor duplex stability
Fewer than 350 valid 21-mer siRNAs	-30 pts	Low siRNA diversity
Homopolymer runs (8+ nt)	-15 pts each	Synthesis difficulty
Hexameric repeats	-10 pts	Off-slippage risk
MFE/nt moderate folding	-10 pts	Secondary structure
MFE/nt heavy folding	-20 pts	Strong secondary structure
UTR region selected	x0.5-0.6	Less effective than CDS

Criterion

Penalty

Rationale

GC content < 30% or > 70%

-20 pts

Poor duplex stability

Fewer than 350 valid 21-mer siRNAs

-30 pts

Low siRNA diversity

Homopolymer runs (8+ nt)

-15 pts each

Synthesis difficulty

Hexameric repeats

-10 pts

Off-slippage risk

MFE/nt moderate folding

-10 pts

Secondary structure

MFE/nt heavy folding

-20 pts

Strong secondary structure

UTR region selected

x0.5-0.6

Less effective than CDS

3-Tier Risk Assessment

Tier	Condition	Action
UNSAFE	Any hit in Homo sapiens	Final Score = 0, ranked last
HIGH RISK	Bee hits > 5	Safety score capped at 40
MODERATE RISK	Water flea hits > 10	Safety score capped at 70
PASS	All checks passed	Full scoring applied

Tier

Condition

Action

UNSAFE

Any hit in Homo sapiens

Final Score = 0, ranked last

HIGH RISK

Bee hits > 5

Safety score capped at 40

MODERATE RISK

Water flea hits > 10

Safety score capped at 70

PASS

All checks passed

Full scoring applied

Species Weights

Species	Weight	Rationale
Homo sapiens	5.0x	Human safety - highest priority
Apis mellifera	3.0x	Beneficial pollinator
Bombus terrestris	3.0x	Beneficial pollinator
Daphnia magna	2.0x	Aquatic ecosystem indicator
Spodoptera exigua	0.5x	Related pest

Species

Weight

Rationale

Homo sapiens

5.0x

Human safety - highest priority

Apis mellifera

3.0x

Beneficial pollinator

Bombus terrestris

3.0x

Beneficial pollinator

Daphnia magna

2.0x

Aquatic ecosystem indicator

Spodoptera exigua

0.5x

Related pest

Final Score = (Quality Score + Safety Score) / 2
Ranked: PASS first, then MODERATE RISK, HIGH RISK, UNSAFE, then by Final Score within each tier.

Disclaimer

For Research Purposes Only. This tool is intended solely for academic and research use. Results should not be used as the sole basis for any commercial, regulatory, or applied pest management decision.

Experimental Validation Required. All dsRNA candidates must be experimentally validated in the laboratory before use in any bioassay, field trial, or application.

No Warranty. This tool is provided as is without warranty of any kind. The developer and the University of Kentucky make no representations about the accuracy or suitability of results for any particular purpose.

Off-target Analysis Limitations. Off-target analysis is performed against available transcriptome databases only. The absence of off-target hits does not guarantee biological safety.

Data Privacy. Uploaded sequences are processed temporarily and are not stored permanently.

By using this tool, you agree to these terms and acknowledge that experimental validation is your responsibility.