isoformsdistinct

Isoformsdistinct is a term used in transcriptomics to describe a framework or metric for identifying and counting distinct transcript isoforms of a gene as observed in sequencing data. It highlights the subset of isoforms that are sufficiently dissimilar in their sequence composition, such as unique exon combinations or splice junctions, to be considered separate products of gene expression.

A typical isoformsdistinct workflow involves assembling RNA-seq reads into transcripts, aligning reads to a reference genome or transcriptome, and annotating the resulting isoforms. Distinct isoforms are distinguished by sequence-level differences and supported by transcript evidence. To reduce artifacts, filters are applied based on minimum read depth, junction confidence, and consistency across samples. The resulting measurements can be reported as a simple isoform count per gene or as a diversity metric that captures the relative abundance and uniqueness of isoforms, enabling cross-gene or cross-condition comparisons.

Applications of isoformsdistinct include assessing isoform diversity across tissues, developmental stages, or disease states, and supporting analyses of differential isoform usage. The concept is useful for studies on regulatory mechanisms governing alternative splicing, promoter choice, and post-transcriptional modification. Researchers must consider limitations such as dependence on annotation quality, sequencing depth, and the accuracy of transcript assembly, which can influence the identification of true distinct isoforms. False positives can arise from sequencing errors or misassembly, while lowly expressed isoforms may be missed.

See also: alternative splicing, transcriptomics, isoform diversity, RNA-seq analysis.