Bioinformatics pipeline · RATION project
Designing safe RNA interference triggers for precision pest management
A computational pipeline that identifies the optimal double-stranded RNA sequence to silence a target gene in a pest organism — while systematically screening every candidate against beneficial species to ensure ecological safety.
Background
RNA interference (RNAi) is a natural gene-silencing mechanism found in nearly all eukaryotic organisms. When double-stranded RNA (dsRNA) enters a cell, it is processed into small interfering RNAs (siRNAs) of approximately 20–23 nucleotides.
Each siRNA is loaded into the RNA-Induced Silencing Complex (RISC), which uses it as a molecular guide to find and degrade any messenger RNA (mRNA) with a matching sequence — effectively switching off the corresponding gene.
As a next-generation biopesticide, a dsRNA can be designed to silence an essential gene in a target pest organism, disrupting its survival or reproduction. No synthetic chemicals are involved, residual activity in the environment is negligible, and — with the right design — effects are highly species-specific.
Analysis pipeline
The input transcript is aligned to the target genome using BLASTn (≥98% identity) to locate the gene's exact chromosomal position.
Subsequences of the chosen siRNA length (15–30 nt, default 20 nt) are generated and assessed for thermodynamic asymmetry, absence of nucleotide runs, and 20–50% GC content.
Candidates are mapped to the target genome via Bowtie. Only siRNAs aligning within the target gene locus advance.
All candidates are mapped against every selected non-target organism genome or transcriptome. Cross-reactive siRNAs are flagged.
A sliding window maximises low-risk siRNAs (primary), then minimises NTO-hitting siRNAs among tied windows as a tiebreaker.
Safety rationale
A poorly chosen dsRNA region — one whose siRNAs happen to match genes in pollinators, fish, or mammals — can trigger unintended gene silencing in non-target species. This is not a theoretical risk: short RNA sequences can align across species boundaries, particularly in conserved gene families.
dsRNA Analyzer makes NTO screening a mandatory, integrated part of the design process rather than a separate afterthought. Every candidate siRNA is tested against every selected non-target organism at a configurable mismatch threshold (default: ≤2 mismatches).
Outputs
Main recommendation table — one row per gene per optimal window
All individual siRNAs passing full QC, specificity, and NTO screening
Per-gene NTO alignment detail for QC-passing siRNAs in the recommended window