A Universal tRNA Adaptation Index Database — quantifying translational efficiency across 8,722 species and 61 sense codons.
A metric for quantifying how well a gene's codon usage matches the tRNA pool of its host organism.
The tRNA Adaptation Index (tAI) measures how efficiently a coding sequence can be translated given the tRNA availability in a cell. Higher tAI values indicate codons decoded by more abundant tRNAs — predicting faster, more accurate translation.
First formulated by dos Reis et al. (2004), tAI requires knowing the copy number (Wi) of every tRNA isoacceptor in a genome. These Wi values incorporate wobble base-pairing rules and isoacceptor redundancy to produce a single per-codon weight.
tAIatlas provides pre-computed Wi values for 8,722 species, enabling large-scale comparative studies of translational selection and codon optimization across the entire tree of life.
Where wi(k) is the relative adaptiveness weight for the k-th codon, and lg is the number of codons in gene g. Each wi is computed from tRNA gene copy numbers weighted by codon–anticodon interaction efficiency (wobble pairing rules).
8,722 species across the Tree of Life. Includes strictly curated Bacterial, Archaeal, and Eukaryotic genomes.
tRNA gene predictions pass tRNAscan-SE quality filters. Pseudogenes and low-confidence calls removed.
Pre-computed Wi values. Download CSV or browse interactively. No bioinformatics pipeline needed.